- "All-Relay" Automatic Telephone Systems — North Electric (1950)
3 pp. PX-1 to PX-500 private exchanges
- "All-Relay" Private Automatic Exchange — North Electric
1 p
- "Give to Ferner": The Untold Story of an American Master Cryptanalyst (Special Series vol. 14)
Robert O. Ferner, co-director of the PURPLE attack; SIS growth 1930–39; J-19 and the GeeWhizzer; B Branch photos (60 pp)
- 119 Practical Programs for the TRS-80 Pocket Computer
John Clark Craig's book of short BASIC programs for the PC-1 and PC-1211 (TAB Books).
- 15 C.F.R. Part 272 — Marking of Toy, Look-Alike, and Imitation Firearms
Applicability, prohibitions, approved markings (§ 272.3), waiver and preemption for imitation firearms; the 1 Jan 2025 CFR edition.
- 15 Teletypewriter Base - Lubrication BSP Section 572-204-701 1964
15 Teletypewriter Base — Lubrication
- 15 Teletypewriter Keyboard - Lubrication BSP Section 572-203-701 1964
15 Teletypewriter Keyboard — Lubrication
- 15 U.S.C. § 5001 — Penalties for Entering into Commerce of Imitation Firearms
The federal statute requiring approved markings on toy, look-alike and imitation firearms.
- 200-, 206-, 209- and 211-Type Selectors and 10-, 26-, 32-Type Banks: Requirements and Adjusting Procedures — AT&T BSP 026-706-701 (1980)
66 pp. Western Electric step-by-step two-motion selectors (the WE 206 type)
- 200-, 206-, 209- and 211-Type Selectors: Piece-Part Data and Replacement Procedures — AT&T BSP 026-706-801 (1965)
16 pp
- 2000 and SE.50 Type Group Selectors (ETP 0258) — Australian Post Office, TPH 1836 (1969)
21 pp
- 28 KSR and RO Teletypewriter Sets
Navy designation ↔ Teletype code chart for KSR/RO components
- 3M Diamond Grade DG3 Reflective Sheeting Series 4090 — Product Bulletin (October 2020)
R_A (coefficient of retroreflection) tables used in the dive's link budget for retroreflective targets.
- 5.56mm Enfield Weapon System: User Handbook (Royal Ordnance, 1985)
Royal Ordnance's user handbook for the SA80 family (copyright 1985; the hosted file is named 1986): technical data, operation, sights, stripping and assembly, cleaning, settings and functional failures. The SA80 dive takes its mechanism, maintenance and stoppage drills from it.
- 580/680 Scientific Computing System — Maintenance Series: 26.268 Digital Voltmeter
Maintenance manual for the EAI Model 26.268 Digital Voltmeter (DVM), a plug-in analog-to-digital conversion unit designed for the EAI 580/680 Scientific Computing System. The DVM provides a five-digit BCD successive-approximation readout over a ±10 V range (20% overrange to ±11.999 V) at 50 or 60 samples per second, with 500 MΩ minimum input impedance and ±0.01% full-scale accuracy. The manual covers physical description, installation, theory of operation (unloading amplifiers, comparator, gated resistor matrix, BCD counters, timing, and power supply), trouble analysis, calibration procedures, replaceable parts, and schematic drawings.
- 680 Scientific Computing System Reference Handbook
This reference handbook covers the EAI 680 Scientific Computing System, a large-scale analog/hybrid computer. It describes all computing components in textbook format, including combination amplifiers, summers, servo-set potentiometers, multipliers, fixed and variable diode function generators, comparators, logic trays, and the patch panel layout. A fully expanded 680 features 156 amplifiers, 120 servo-set pots, 24 multipliers, 18 variable DFGs, and 24 comparators; the handbook guides programmers from machine organization and the signal selector system through mode control, time scale selection, and appendices on specific applications and scaling techniques.
- 7000 Analog/Hybrid Computing System
Sales brochure for the Comdyna 7000 Analog/Hybrid Computing System, a modular building-block hybrid computer configurable as a general-purpose analog computer, hybrid computer, digital-computer peripheral, small processor, or large simulator. The system's centerpiece is MICROPATCH, a digital-computer-controlled patch-programming subsystem that stores, recalls, and modifies analog patch configurations under software control. The brochure also covers the GP-10 analog computing unit, the Control Unit with repeat and hold modes, and analog-to-digital conversion hardware for interfacing with external digital computers.
- 756A PBX Circuit Description Binder (CD-65741-01 and others)
About 30 circuit descriptions for the 756A crossbar PBX: line link and marker, dial-pulse register, junctors, trunks (465 pp.).
- 808 Analog Signal Processor
A product brochure for the Comdyna 808 Analog Signal Processor, a low-cost analog computer designed to process raw instrumentation measurement data in real time. The 808 provides eight operational amplifiers with wide frequency range, summation, integration, and coefficient multiplication, plus signal conditioning elements such as precision potentiometers and overload indication, enabling it to bridge raw instrumentation signals and digital data acquisition systems. Typical applications described include implicit measurement, data reduction, process control, and preprocessing of digital computer inputs.
- 808 Analog Signal Processor Operator's Manual
Operator's manual for the Comdyna 808 Analog Signal Processor, a standalone or peripheral analog computer unit with ten 2K coefficient potentiometers, an 11-position amp/pot address switch, a 3-position mode selector (IC/OP/Hold), and a 25-pin trunk and readout connector. The manual covers internal features, patch panel operations, trunk connector pin assignments, system schematics, assembly drawings and parts lists for the quad amplifier and power supply boards, and adjustment procedures for the Model 982 dual multiplier network and the Model 731 variable diode function generator.
- A 240-Character Vacuum Fluorescent Display (SID Digest, 1979)
Ise's SID paper on a 240-character dot-matrix fluorescent display, the step beyond calculator digits.
- A CBI SIGABA Near-Miss
Hengyang airstrip evacuation, May 1944; rotors lost in the river (2 pp.) [writer A]
- A Closer Look at the Compensating Polar Planimeter (Eggers, 2020)
College Mathematics Journal 51:2 (2020): the mathematics of the compensating polar planimeter, showing that averaging pole-left and pole-right readings exactly cancels a misaligned wheel.
- A Comparison of Proposed Small Arms Weapon Systems — BRL Memorandum Report No. 1139 (1958)
A Ballistic Research Laboratories comparison of proposed small-arms systems, April 1958. The Hyper-Burst Mechanisms dive cites it among the post-SALVO studies of multiple-projectile and burst weapons.
- A Contribution to the History of Planimeters (Vossepoel & Zerfowski, 2023)
Slide Rule Gazette 23 (2023): more than 30 lesser-known planimeters of 1814–1884.
- A Discussion of Proposals by Vendors for the Hybrid Simulation Equipment for the C-3 Project (LMSC)
Transcription of a March 1966 presentation by J. E. Sherman, Manager of Analog and Hybrid Computing at LMSC, to approximately 40 personnel covering the selection process for a hybrid computing center in Building 181 for the C-3 Project. The document evaluates proposals from Electronic Associates Inc. (EAI), Astrodata, and Beckman, and includes charts describing the hybrid system concept (analog computer + interface + digital computer) and a proposed configuration with dual CPUs sharing 48K common storage connected via interfaces to four analog computers. Serves as an internal procurement evaluation record.
- A Fowler's Gallimaufry (2nd edition, Version 2)
The fullest catalogue of Scientific Publishing Co. and Fowler pocket-watch calculators: the Mechanical Engineer and early SPC types; Fowler's patents (5,528/1910, 20,416/1913, 3,638/1914, 15,990/1914, 215,648/1924); design changes (sintered cast cases, two-part pressed-steel knurled cases, late smooth 'chromed' sintered cases c.1948); every type with photographs — Fowler's Calculator, Types A, A1, B Textile, E, E1, H, M, O, R, RX, T, short- and long-scale Textile, Magnum Textile, Vest Pocket MD/H/CSR, Universal, Universal Blitz-Rechner, Twelve-Ten, Magnum Long Scale, Jubilee Magnum, Nautical, Artillery, Long Scale, Circular Slide Rule, Junior, Kearns, Mackay, Ribble; Bakelite backs; a feature-by-feature dating table (loops, winders, address banners, FC logo); cases and tins; workshop photographs; chronology; serial-number appendix; documents appendix.
- A History of Engineering and Science in the Bell System: Switching Technology (1925-1975)
Authoritative history of Bell switching including SxS, panel, crossbar and ESS.
- A History of Pocket Computers 1980–2000
Roland Saam's paper for IEEE HISTELCON 2019 on the pocket computers of 1980–2000, their makers, prices and uses.
- A Machine for Combining Sets of Linear Congruences (Math. Annalen 109, 661–667)
Lehmer's account of the photoelectric gear sieve: gears of 67–128 teeth, its speed, and how problems were set up.
- A Mannheim Type Slide Rule (with A, B, C, D, CI, K, S, T, L scales) — Frederick Post Co. instruction leaflet
Early Post leaflet for its Hemmi-made Mannheim rules (ISRM files it under the early model 1447, the sibling of the Hemmi 30/32 pocket rules). Describes the parts, locating numbers, and the operations; recommends freeing a tight slide with paraffin oil, paraffin wax or sandpaper. Undated (pre-Teledyne). 6 pp.
- A Method for Obtaining Digital Signatures and Public-Key Cryptosystems (CACM 21(2))
The original RSA paper, whose security rests on the difficulty of factoring.
- A Method of Factoring and the Factorization of F7 (Math. Comp. 29, 183–205)
The continued-fraction factoring method and its sieve-like factor base, used to factor F7.
- A Model of the Cosmos in the Ancient Greek Antikythera Mechanism
Scientific Reports 11:5821 (CC BY 4.0). The UCL reconstruction of the planetary display as nine concentric rings, from the 462/442-year inscription periods.
- A Model of the Cosmos in the Ancient Greek Antikythera Mechanism — Supplementary Information
Supplementary information to the 2021 UCL model: gear trains, period relations and CT evidence.
- A New Digital-Attenuator System for Hybrid Computers
NASA Contractor Report CR-87287 describing a digital attenuator system for analog/hybrid computers, developed at the University of Arizona's Analog/Hybrid Computing Laboratory. The system uses miniature metal-film ladder networks switched by latching reed relays for nondestructive coefficient memory, with serial data transmission allowing all 200 attenuators of a typical hybrid computer to be set within 20 milliseconds. The design replaces conventional servo-driven potentiometers to dramatically reduce problem setup time.
- A new stream cipher based on Fialka M-125
Mathematical description of the Fialka cipher and a stream cipher derived from it; states "there are no known attacks on this cipher"
- A Practical Approach to Analog Computers
An 11-page introductory article, reprinted from Instruments & Control Systems (Vol. 35, No. 8, August 1962) and issued as EAI Applications Reference Library Computing Techniques 1.8.1, that explains analog computation to engineers unfamiliar with the field. It covers the basic building blocks of general-purpose analog computers—high-gain amplifiers, summing amplifiers, potentiometers, integrators, servomultipliers, and diode function generators—and demonstrates how to translate differential equations into patch-panel programs, using a simple pendulum problem as a worked example. The PACE 231R computer is illustrated as the representative hardware platform throughout.
- A Practical Treatise on Brewing - 4th Ed
- A Practical Treatise on Malting and Brewing
- A Revision for the Draconic Gearing of the Antikythera Mechanism, the Eclipse Events of Saros Spiral and their Classification
arXiv:2412.07023. Revised draconic gearing and a classification of the Saros eclipse events.
- A Runlet of Ale
- A Simple and Inexpensive Implementation of Time Division Multiplier for two Quadrant Operation
A four-page technical article published in IETE Technical Review (Vol. 12, No. 1, 1995) presenting a simple, low-cost two-quadrant time division multiplier (TDM) circuit built from standard CMOS and linear ICs. The circuit uses a sawtooth waveform generator, a comparator, and a low-pass filter to produce an output voltage proportional to the product of two input voltages. Experimental results tabulate accuracy within about 0.1% error for supply voltages up to ±5 V.
- A Survey on Analog Models of Computation
A comprehensive academic survey covering analog models of computation from both the historical 'computing by analogy' and the mathematical 'working on the continuum' perspectives. The paper systematically classifies models (GPACs, neural networks, BSS machines, hybrid systems, reaction-diffusion systems, population protocols, and more) along discrete/continuous time-space axes, with emphasis on computability and complexity theory. Published as a chapter in the Springer Handbook of Computability and Complexity in Analysis (2021); arXiv preprint 1805.05729.
- A Tale of Two Sieves (Notices of the AMS 43(12), 1473–1485)
Readable history of the quadratic sieve and the number field sieve.
- A Test of Salvo Rifle Material (Aberdeen Proving Ground, 1957)
An Aberdeen Proving Ground test report (declassified) on SALVO-programme materiel, including duplex and triplex rounds fired from modified M1 rifles and flechette loads from a shotgun. Held with the Hyper-Burst Mechanisms dive's SALVO sources; not cited in its volumes.
- A Theoretical and Practical Treatise on Malting and Brewing
- A Treatise on Brewing Wherein is Exhibited the Whole Process of the Art and Mystery of Brewing
- A Treatise on Family Winemaking
- A Treatise on Planimeters: Theory, History and Different Varieties (Frost, 2025)
Lecture slides from the Oughtred Society's 2025 international meeting: the history, theory and many varieties of planimeter.
- A Treatise on the Art of Making Wine from Native Fruits
- A Treatise on the Brewing of Beer
- A Treatise on the Culture of the Vine and the Art of Making Wine
- A Very Fast Electronic Number Sieve (PhD thesis, University of Manitoba)
Thesis describing the MSSU electronic sieve, with a history of sieving devices in section 1.6.
- A View of the Management of Fruit Trees and the Management of Orchards and Cider
- A Week-End Off: The First Extensive Number-Theoretical Computation on the ENIAC (CiE 2008, LNCS 5028, 158–167)
How D. H. Lehmer, helped by Emma Lehmer and John Mauchly, used a July 1946 weekend to run the first extensive number-theoretical computation on the ENIAC: the exponent of 2 modulo primes.
- A Word About E.S.R. Inc. (flyer)
E.S.R.'s trifold company flyer showing its product line.
- A-TEC MP7 Suppressor — Catalogue Data (2020)
A-TEC's 2020 catalogue data for the MP7 suppressor, cited alongside the 2023 sheet by the HK MP7 dive.
- A-TEC MP7 Suppressor — Data Sheet (2023)
A-TEC's 2023 data sheet for its all-steel MP7 suppressor. Cited by the HK MP7 dive's suppressor section.
- A123 Systems ANR26650M1-B Nanophosphate High Power Lithium Ion Cell — Data Sheet (MD100113-01)
The LiFePO4 reference cell.
- Absolute Beginner's Guide to the NanoVNA
- Accessories Programme MP7 A1, 4.6 mm × 30 (Heckler & Koch, 2012)
H&K's catalogue of MP7A1 accessories (v003.09.12). The HK MP7 dive cites it for the factory accessories, suppressors and mounts.
- Acorn Support Group Application Note 238 — Connector Pinouts (Electron, BBC B/B+, Master)
2 August 1993 connector reference: analogue port pin 9 is the light-pen strobe (LPSTB).
- ACT Calculator Policy
ACT's calculator policy: which calculators are allowed and prohibited in the ACT test.
- AD633 Low Cost Analog Multiplier Data Sheet
Complete datasheet (Rev. K, 2015) for the Analog Devices AD633, a functionally complete four-quadrant analog multiplier IC available in 8-lead PDIP and SOIC packages. The transfer function is W = (X1-X2)(Y1-Y2)/10V + Z, with 1 MHz bandwidth, 20 V/µs slew rate, and laser-trimmed total error within 2% of full scale; supply voltages range from ±8 V to ±18 V. The document covers electrical specifications, pin configurations, functional description, error sources, and application circuits including squaring, frequency doubling, division, square rooting, variable scale factor, amplitude modulation, voltage-controlled low-pass and high-pass filters, quadrature oscillator, AGC amplifiers, and SPICE simulation examples in Multisim, PSPICE, and SIMetrix.
- AD633-EP Low Cost Analog Multiplier
Datasheet for the AD633-EP, a functionally complete four-quadrant analog multiplier IC in an 8-lead SOIC package, specified over the -55°C to +125°C military temperature range. The device implements the transfer function W = (X1-X2)(Y1-Y2)/10V + Z, with laser-trimmed total accuracy within 2% of full scale, 1 MHz bandwidth, 20 V/µs slew rate, and supply voltages from ±8 V to ±18 V. Applications covered include multiplication, division, squaring, modulation/demodulation, phase detection, and voltage-controlled amplifiers and filters.
- ADC Voltage Reference Buffer Optimization Reference Design for High-Performance DAQ Systems
This Texas Instruments reference design (TIDA-01055, document TIDUDE2A) presents an optimized two-stage composite voltage reference buffer for driving the REF pin of an 18-bit, 2-MSPS SAR ADC (ADS9110) in high-performance DAQ systems. The design uses a REF5040 4.096 V reference combined with an OPA378 precision op-amp and an OPA837 high-speed op-amp in a composite configuration, achieving a system ENOB of 15.77 bits at 1.94 W total power—a 22% power improvement over the conventional OPA625-based approach. The document covers stability, noise, power, and transient analysis via TINA-TI simulation, hardware jumper configuration, PCB layout recommendations (thick versus thin trace comparison), and measured performance results across multiple buffer and reference options.
- Additional Elements of Hitachi 505 Necessary for Hybrid Computing System
Technical Information Series No. 1 (2nd edition) from Hitachi, Ltd., describing the additional hardware elements required to upgrade the Hitachi 505 analog computer into a hybrid computing system. Covers the hybrid linkage configuration, voltage comparator CP-153, servo-set potentiometer panel SP-251, servo-set function generator panel SFG-251, selector-setter panel, and servo-set console, along with signal specifications for D/A and A/D converters, external control inputs, clock signals, and interlock control between the analog and digital subsystems.
- Adjustments for Uniselector, Single Magnet (B.P.O.) Type No. 2 — Automatic Telephone & Electric Co., E.A. 854 issue 7
19 pp. Uniselector mechanism and adjustment, the class of switch used in PURPLE
- Advanced Combat Rifle (ACR) Program, Volume I, ACR Program Summary — ARCCD-TR-92001 (1992)
The US Army's summary report of the Advanced Combat Rifle programme (Picatinny Arsenal, February 1992; DTIC AD-B162 942), with the contractor synopsis in Appendix B. The Hyper-Burst Mechanisms dive's main source for the H&K G11 and the other ACR entries in the US test; the Daisy dive cites it on caseless ammunition.
- Adwater & Stir µKENBAK-1 Assembly Booklet V2
µKENBAK-1 kit assembly booklet, version 2.
- AE 1957 dial equipment catalogue excerpt
Excerpt of AE dial central-office equipment catalogue.
- AE 58466 Test Connector circuit
Drawings for an AE test connector circuit (switch that connects the test desk to subscriber lines).
- AE Bulletin 505: Lubrication of Automatic Switching Equipment
Lubrication points and schedules for Strowger equipment.
- AE Communications Service Guides (28 issues) — Automatic Electric (1960)
140 pp. PABX/PBX product guides (25M, 40B, 80A, 100T, 300-series, L55 ...)
- AE Training 800: Elementary Principles of Telephony, part 2
Earlier edition excerpt of AE training 800.
- AE Training Bulletin 800: Electrical Principles of Telephony
First booklet of AE's Strowger training series: electrical basics.
- AE Training Bulletin 801: Mechanical Principles of Telephony
Mechanics of relays and Strowger switches.
- AE Training Bulletin 802: Fundamentals of Apparatus and Trunking
How linefinders, selectors and connectors are trunked together.
- AE Training Bulletin 805: The Plunger Line Switch and Associated Master Switch
Keith plunger line switch and master switch operation.
- AE Training Bulletin 806: The Rotary Line Switch
Rotary line switch (preselector) operation.
- AE Training Bulletin 807: The Connector
AE connector switch operation and circuit; key for a small PBX.
- AE Training Bulletin 808: The Selector
AE selector switch operation and circuit.
- AE Training Bulletin 810: Pulse Repeaters
Pulse repeater operation.
- AE Training Bulletin 812: Power and Supervisory Equipment
Exchange power plant, ringing machines, tones, alarms.
- AE Training Bulletin 813: Party-Line Connectors and Trunk-Hunting Connectors
Connector variants for party lines and hunting groups.
- AE Training Bulletin 815: The Test and Verification Switch Train
Explains AE test distributors, test connectors and verification switches used to test lines and switch trains.
- AE Training Bulletin 818: P-A-X's with P-A-B-X Appendix
Private automatic exchanges and PABXs: the system-level guide for a small home PBX.
- AE Training Bulletin 821: Linefinder Switches
Linefinder switch operation and allotter.
- AGS 14 Calculator: Reverse-Engineered Schematic
Schematic of the AGS 14 pocket calculator of 1975 with a nine-digit fluorescent tube.
- AL304 Seven-Segment LED Indicator Datasheet (in Russian)
Datasheet of the AL304 gallium-arsenide-phosphide seven-segment LED digit of the kind used in early Soviet LED calculators (in Russian).
- Albert Nestler A.-G., Lahr (Baden) — Rechenschieber catalogue
Pre-war Nestler trade catalogue. Lists the Original-System Rietz No. 23/1 and 23/3 and, flagged 'Neu!', the Original-Modell Rietz with reciprocal and extended scales No. 22R/3, 23R/1, 23R/3, 23aR/1, 24R/3, 24R/1 — mahogany with white celluloid scales — and explains the D.R.P. 410565 steel-spring stock that made adjusting screws unnecessary.
- Ale Brewer s Assistant
- Ale in Prose and Verse
- Aliens Armageddon — Setup and Operation Service Manual (rev. AA-1.00-1.28.14-1)
Camera assembly, gun potentiometers and the solenoid knocker.
- Allegro A1324 / A1325 / A1326 Low-Noise Linear Hall-Effect Sensor ICs — Datasheet
Ratiometric analogue linear Hall sensors; 4.5–5.5 V supply, which is why the light-gun trigger design rejected them for a 3.3 V board.
- Alpha & Omega AO3400A 30 V N-Channel MOSFET — Datasheet
SOT-23 logic-level MOSFET specified at VGS = 2.5 V; the rumble-motor switch in the reference electronics.
- Alpha & Omega AOD4184A 40 V N-Channel MOSFET — Datasheet
The part on the common 'D4184' hobby MOSFET modules; gate threshold up to 2.6 V, which matters when driving it from a 3.3 V microcontroller.
- Alps Alpine SKRH Series 4-Direction Switch with Center Push — Catalogue Sheet
The picked five-way switch (SKRHABE010).
- American Planimeters (Otnes, 2002)
Journal of the Oughtred Society 11:2 (2002): the planimeters sold in America, K&E's suppliers (Amsler, Coradi, Haff, Ott), and their uses.
- American Telephone Practice (4th ed.)
Standard reference including the early automatic exchange chapters.
- Amiga Hardware Reference Manual, 3rd Edition
'Reading a light pen': the beam-trigger pin 6, the VPOSR latch and port selection by model. Downsampled to 150 dpi.
- ams OSRAM AS5600 12-bit Magnetic Rotary Position Sensor — Datasheet (v1-06)
Contactless angle sensor for a mounted (positional) gun's axes.
- ams OSRAM AS5600L 12-bit Magnetic Rotary Position Sensor — Datasheet
AS5600 variant with a programmable I2C address, so two axes share one bus.
- ams OSRAM SFH 4547 850 nm Infrared Emitter — Datasheet (v1.7)
5 mm high-power 850 nm IR LED; the emitter OpenFIRE's guides name.
- Amstrad CPC6128 — User Instructions
Joystick and expansion socket pinouts (L.PEN on pin 47) and the LP-1 light pen. Downsampled to 150 dpi.
- An Analog Computer Model of a Multiple-Region Reactor
ANL-6482 is a 1962 Argonne National Laboratory technical report describing an analog computer technique for solving the time-space-dependent neutron diffusion equation for a multiple-region reactor. The method handles fuel burnup, fission product and xenon-iodine poison buildup, and control poison injection while maintaining constant power, using interregion neutron diffusion expressed as a surface integral to achieve accurate flux plots with only six spatial points. Complete circuit diagrams, potentiometer settings, scaled equations, and comparison with digital results are provided.
- An Analog Computer Study of the Effectiveness of Interceptor Commands Derived from a Prediction Equation of Second Order
NASA Memorandum 10-7-58A from Ames Research Center presenting an analog computer study comparing first-order and second-order prediction equations for automatic interceptor guidance on lead-collision courses against maneuvering targets. The authors derive second-order prediction equations that allow the interceptor to fly a straight-line course against a target with constant acceleration, then use an analog computer to analyze system stability and evaluate rocket miss distance under various conditions including limited/unlimited interceptor acceleration, constant and pulse target maneuvers, and varying rocket speeds. Results demonstrate improved miss distance performance with second-order commands compared to first-order prediction schemes.
- An Announcement Concerning the Delay Line SIEVE DLS-127 (Math. Comp. 20, Notes, 645–646)
Announcement of the Delay Line SIEVE DLS-127, Lehmer's electronic successor to the mechanical sieves.
- An Application of Hybrid Curve Generation: Cartoon Animation by Electronic Computers
Conference paper from the 1967 Spring Joint Computer Conference describing two hybrid-computer methods for automating cartoon animation. The analog method generates pictures on a CRT by modifying circles via transformation circuits on the Hitachi ALS-2000; the hybrid method reads animator-drawn keyframes into a digital computer, calculates tangents by parabolic approximation, and uses analog elements to interpolate smooth curves between frames. Mathematical details of both linear and similarity-based frame interpolation are provided.
- An Efficient Orientation Filter for Inertial and Inertial/Magnetic Sensor Arrays
The 30 April 2010 internal report that introduced the Madgwick gradient-descent orientation filter.
- An Electromechanical Telephone Exchange (PoC||GTFO 21:08)
Hobbyist build of a small exchange from stepping switches, with circuits: a practical model for a small home PBX.
- An Elementary Dictionary (of the brewers trade)
- An Elementary Treatise on American Grape Culture and Wine Making
- An Essay on Brewing with a View of Establishing the Principles of the Art
- An Essay on the Inventions and Customs of Both Ancients and Moderns in the Use of Inebriating Liquors
- An Improved Calendar Ring Hole-Count for the Antikythera Mechanism
Horological Journal, July 2024 (arXiv:2403.00040). Bayesian analysis giving 354 or 355 holes — a lunar calendar.
- An Introduction to Prime Number Sieves (UW–Madison CS Technical Report 909)
Survey of prime-number sieve algorithms — Eratosthenes, wheels, segmented and linear sieves — with their running times.
- Analog and Hybrid Computer Programming
A comprehensive textbook by Prof. Dr. Bernd Ulmann covering the theory and practice of programming analog and hybrid computers, from foundational computing elements (summers, integrators, multipliers, potentiometers, comparators) through basic and advanced programming techniques, special functions, and a wide range of application examples including chaotic attractors, celestial mechanics, and partial differential equations. All worked examples are implemented on the Analog Paradigm Model-1, with discussion of how setups translate to classic EAI and Telefunken machines. The book also addresses hybrid computer architectures that couple analog and digital processors, and includes appendices on Laplace transforms and operational calculus.
- Analog and Hybrid Computing
A 66-page slide-presentation by Bernd Ulmann (vaxman.de), dated 1 May 2006, giving a broad introduction to analog and hybrid computing. It progresses from early mechanical analog devices (slide rules, planimeters, differential analyzers) through electronic analog computer fundamentals and on to hybrid digital–analog systems, covering core computing elements, programming techniques, and practical problem-solving examples.
- Analog Computer Application Bulletin No. AB-856: Process Control Problems Yield to the Analog Computer
EAI Application Bulletin No. AB-856, reprinted from Control Engineering, demonstrates how an analog computer can simulate a batch chemical process and its cascade control system to determine optimum controller settings and valve configurations. The bulletin covers mathematical modeling of the kettle, water jacket, and steam/cooling systems using integrators, multipliers, and potentiometers, with example simulation runs comparing single-loop and cascade control strategies. Results show that the cascade system substantially outperforms single-loop control in rejecting disturbances such as sudden steam-pressure changes.
- Analog Computer Fundamentals: With an Introduction to Matrix Programming Methods
A 1962 instructional textbook by Silvio O. Navarro, Associate Professor of Electrical Engineering and Director of the Computing Center at the University of Kentucky, covering analog computer fundamentals and matrix programming methods. The text introduces basic analog building blocks (potentiometers, operational amplifiers, adders, integrators, function generators, multipliers), techniques for solving ordinary and partial differential equations on analog computers, machine components and patching, and an advanced chapter on matrix-based programming methods for systematic problem setup. Produced under the Ford Foundation Project on the Use of Computers in Engineering Education and distributed through Wadsworth Publishing Company.
- Analog Computer Prototyping for the Future
Master's thesis from Malmö University (2022) documenting the design and construction of a low-cost modular single-board analog computer capable of solving second-order differential equations. The project follows design science research methodology (DSRM) and evaluates two hardware revisions (V1 and V2) through demonstration problems including Mathieu's differential equation and a spring-mass damping system. The paper argues that accessible analog and hybrid analog-digital systems are a viable path toward more energy-efficient future computing.
- Analog Computer Techniques
A 1956 textbook by Capt. Clarence L. Johnson (USAF, U.S. Air Force Institute of Technology) covering the theory and practical use of electronic analog computers (differential analyzers). Topics range from linear computing components, amplitude and time scaling, and synthesis of servomechanism systems, through nonlinear and function-generating techniques, repetitive analog operation, and a concluding introduction to digital differential analyzers. The book was developed from computer courses taught to undergraduate and graduate students at Wright-Patterson Air Force Base and is pitched at readers with knowledge of Ohm's law, Kirchhoff's laws, and basic differential equations.
- Analog Computers in Process Design (Application Bulletin No. 3)
EAI Application Bulletin No. 3, authored by Charles W. Worley, demonstrates the use of PACE analog computers in the simulation and design of industrial process control systems. The bulletin covers analog circuit setups for pneumatic proportional-plus-reset controllers, heat exchangers, distillation column material balances, first-order chemical reactions, and catalytic reactors, with governing differential equations and corresponding computer patch diagrams for each. A reference table of PACE general-purpose analog computer component symbols is appended.
- Analog Computers: RCA Typhoon, 1951
A descriptive article covering the RCA Typhoon, built under Navy Bureau of Aeronautics contract and entering service in early 1951 as one of the largest analog computers ever made, housing approximately 4,000 vacuum tubes in 43 racks. The machine featured 450 precision DC amplifiers, 20 computing servo units with multipliers, up to 80 simultaneous integrations, and ultra-stabilized power supplies regulated to 0.001% of full scale. The article draws on Electronics magazine issues from 1951 and describes architecture, circuit details, and operational requirements of the system.
- Analog Computing, 2nd Edition
A comprehensive 460-page academic textbook covering the history, theory, and practice of analog computing from mechanical devices (Antikythera mechanism, slide rules, differential analysers) through classic electronic analog computers to hybrid and digital differential analyser systems. The book addresses basic computing elements (op-amps, integrators, summers, multipliers, function generators), programming techniques including scaling and partial differential equations, and an extensive survey of real-world applications spanning aerospace, nuclear engineering, biology, economics, and the arts. A final chapter covers the decline of analog computing in the late 1970s and its anticipated renaissance in low-power computing, AI, and high-performance computing.
- Analog Devices ADXL1001 / ADXL1002 Low-Noise High-Frequency MEMS Accelerometers — Datasheet (Rev. A)
Single-axis analogue ±100 g / ±50 g MEMS accelerometers with a DC–11 kHz response; a candidate for measuring solenoid recoil impulses on the bench.
- Analog Devices ADXL375 3-Axis ±200 g Digital MEMS Accelerometer — Datasheet (Rev. B)
Three-axis ±200 g digital (SPI/I2C) accelerometer with a FIFO and shock detection; the digital alternative for recoil measurement.
- Analog Devices Maxim DS1307 real-time clock
- Analog Devices Maxim DS3231 real-time clock
- Analog Devices TMP35 / TMP36 / TMP37 Low-Voltage Temperature Sensors — Data Sheet (Rev. H)
Analogue temperature sensors; the TMP36 is the one the OpenFIRE firmware reads to protect the solenoid.
- Analog Dialogue: Editor's Notes and Versatile New Module Y(Z/X)^m at Low Cost
A two-page excerpt from Analog Devices' Analog Dialogue journal, comprising an Editor's Notes page and an article on the Model 433 'Versatile New Module.' The article describes log-antilog techniques for performing Y(Z/X)^m computations (multiply, divide, exponentiate) with 0.5% FS error and 100:1 denominator range at low cost. Typical applications include true-rms measurement, curve fitting, linearization, and sophisticated analog instrumentation.
- Analog/Hybrid — What It Was, What It Is, What It May Be
A survey article by Arthur I. Rubin of Electronic Associates, Inc. (EAI), presented at the Fall Joint Computer Conference (FJCC) 1970. It traces the evolution of analog and hybrid computers from WWII 'zeroth generation' machines (BEAC, EASE, GEDA, REAC) through successive generations defined by patch panels, improved component accuracy, and the introduction of digital elements, to the hybrid systems of 1970, and speculates on their future. Key manufacturers (EAI, Beckman/Berkeley, Reeves, Philbrick, GPS) and landmark machines are discussed alongside accuracy milestones, application domains, and the historical tension between analog flexibility and digital precision.
- Analogrechner AR 12
Technical description and operator manual for the Frey Analogrechner AR 12, a compact 19-inch desktop analog computer with 12 computing amplifiers (6 integrators, 6 summing amplifiers), 5 computing voltages, and 5 computing potentiometers housed on Eurocard plug-in boards. Covers operating principles, front-panel controls and jack-field layout, calibration and offset-adjustment procedures, individual plug-in card specifications (RB 23 amplifier, RB 24 integrator, RB 37 oscillator, RB 89 HF filter, RB 91/SN power supplies), and a 1973 price list with three model variants ranging from DM 2,580 to DM 5,420.
- Analogrechner Do 80 / Analog Computer Do 80
Bilingual German/English product brochure for the Dornier Do 80, a compact 10 V, 19-inch rackmount analog computer manufactured by Dornier System GmbH. The brochure covers the machine's control and indicator elements, computing element modules (integrators, summers, multipliers, variable function generators, logic modules, counters, and death-time delay generators), patching examples for common mathematical operations, and full technical specifications. Key specs include ±10 V reference, 220 V/50 Hz supply (~100 VA), summer bandwidth of 80 kHz, integrator capacitors of 1 µF/0.1 µF/0.01 µF, and TTL logic components.
- Analogrechner DORNIER 240
Technical brochure describing the DORNIER 240, a fully transistorized precision desktop analog computer operating at a 10 V computing voltage with up to 49 computing amplifiers in full configuration. The document covers the machine's modular architecture, patch panel layout, operating modes, and computing elements including summing integrators, summers, parabola multipliers, variable diode function generators, hand potentiometers, and an optional TTL logic supplement. Key features include amplifier bandwidth exceeding 350 kHz, addressable computing elements, repetition frequencies up to 78 Hz, and interchangeability of elements with the DORNIER 720.
- Analogrechner Dornier 720
Product brochure for the Dornier 720, a fully transistorized precision analog computer operating at 10 V with a modular architecture supporting up to 145 amplifiers, of which 36 can serve as electronically controlled integrators. The brochure covers the display and control panel, optional logic add-on with 24 flip-flops and counters, application areas spanning control engineering, aerospace, chemistry, and education, hybrid computing integration (electronic servo-potentiometers with 10 ms setting time), and a detailed breakdown of the six-sector programming board with module-level component listings.
- Analogrechner Dornier 80 Bedienungs-Handbuch
Operating manual for the Dornier DO 80 analog computer, published January 1976 by Dornier System GmbH, Friedrichshafen. Covers the front-panel controls and rear-panel connections of the DO 80, including the 16 plug-in computing-element positions, potentiometer and timing controls, operating modes (IC, single-run, repetitive), remote-control interface, and voltmeter subsystem. Intended both as a beginner operating guide and a reference for special circuit configurations.
- Analogrechner für den Lehrer (Analog Computer for the Teacher)
Teacher's supplement for PEK Electronic analog computer laboratory exercises, dated January 1972. Each sheet (A 1350–A 1360) corresponds to a student exercise and provides instructors with expected measurement results, circuit analysis notes, and pedagogical guidance for topics including sawtooth waveform generation, step-function generation, factor formation, summation, integration, differential equations, parabola multipliers, servo-multipliers, and PID controller construction.
- Analogrechner Versuche 1: Versuchsbeschreibungen für Platte 38500
A set of three guided laboratory experiments for the PEK Electronic 38500-series analog computer system, published January 1972. The experiments cover: (1) measuring integrator output voltage as a function of time with various time constants using Board 38503; (2) generating and observing step functions (Z-Sprung) using the integrator and oscilloscope with Board 38501; and (3) measuring the voltage transfer characteristics of the three potentiometer types (P1–P3, P4–P9, P10–P15) on Board 38501 to understand coefficient scaling. Equipment referenced includes Boards 36013, 38501, 38503, 38506, 38508, and 38509.
- Analogue Computer (Part 1)
A multi-part constructional article from Practical Electronics magazine (September 1978, Vol. 14 No. 13) describing how to build a general-purpose analogue computer. Part 1 covers the mathematical operations achievable with op-amp circuits — summation, integration, and coefficient multiplication — and explains how these building blocks are interconnected to simulate physical systems. Practical circuit diagrams and example applications (velocity, distance, oscillatory motion) are included alongside theory.
- Analogue Tutor TY1351 Instruction Manual
Instruction manual for the Solartron Analogue Tutor TY1351, a bench-top operational amplifier computer designed specifically for educational use in training students on analog computation techniques. Covers circuit description, amplifier circuitry (including summer/integrators, reference supplies, and the AS1403 Power Supply Unit), initial checkout procedures, and a list of components. Published May 1964 by The Solartron Electronic Group Ltd., Farnborough, Hants.
- Analyse von natürlichem Modellseegang
A 1968 journal article (Schiffstechnik, Vol. 15, No. 75) by Dipl.-Ing. S. Kastner describing the design and construction of a special electro-mechanical analog analyzer for real-time spectral analysis of natural sea states during ship model stability tests. The instrument uses sine-cosine potentiometers driven by a synchronous motor to compute Fourier coefficients in the 0.25–1.5 Hz range (wavelengths 0.7–25 m), with 40 RC-integrator storage channels (τ = 1200 s, 4-minute integration cycles); the paper compares this approach to analog-computer filter circuits, digital methods, and drum-scanning techniques.
- Analysis and Optimization of the TWINKLE Factoring Device (Eurocrypt 2000)
Analysis of TWINKLE, Shamir's optoelectronic sieve that echoes Lehmer's photoelectric machine.
- Analysis of Rolling Theory by Analog Computer — Karman's Differential Equation —
Technical Information Series No. 8 from Hitachi's Analog-Hybrid Computer line, demonstrating how an analog computer automatically solves Karman's differential equation to determine pressure distribution and rolling load during metal rolling. The document derives the governing equations (boundary-value problem, projected contact length, elastic deformation), describes the analog circuit design with five integrators and a program controller, and validates results against digital computer solutions across six parametric cases. Computation time is on the order of seconds versus minutes for digital approaches.
- Anleitung — Castell Präzisions-Rechenstäbe Novo-Duplex Nr. 2/83, 62/83
Scanned original German instruction booklet for the Novo-Duplex 2/83 and 62/83 — the immediate predecessor of the 2/83N (no A, B, DI, LL00 or back-face CI/D/LL0). The method text is substantially the one carried over into the 2/83N manual, including the Geroplast care note (Vaseline or silicone oil for the slide; Castell No. 211/212 cleaners; no strong solvents, which attack the colour of the graduations).
- Anleitung zur Kenntnis und Behandlung der Pistole 1900/06 (Swiss Army, 1911)
The Swiss Army's manual for the Parabellum Pistole 1900/06, approved by the Federal Council on 31 January 1911: parts, accessories, stripping and assembly, handling, functioning, cleaning, ammunition and data. The Luger P08 dive takes the Swiss service data (7.65 mm, four grooves, one turn in 250 mm) and the takedown from it.
- Anschreiben: HYDAC Digital-Analog Computer Series 2000 (EAI European Division an Prof. Dr. K. H. Weise)
A one-page sales letter in German dated 28 June 1962 from Hans H. Brüggemann, Sales Engineer at EAI Electronic Associates Inc. European Division (Brussels), addressed to Prof. Dr. K. H. Weise at Kiel University. The letter introduces the HYDAC Digital-Analog Computer Series 2000, noting that the standard PACE 231R analog computer is a core component and that existing PACE 231R installations can be upgraded into a full HYDAC hybrid system. A product brochure and a data sheet for the Microstore Model 2.395 are mentioned as enclosures.
- ANSI/SAAMI Z299.3-2022 — Pressure and Velocity of Centerfire Pistol and Revolver Ammunition
SAAMI's American National Standard for centerfire pistol and revolver ammunition: pressure and velocity tables, test methods and cartridge and chamber drawings (approved 13 December 2022). Cited for cartridge pressures and dimensions by the HK Mk23, Ruby Pistol and HK MP7 dives.
- ANSI/SAAMI Z299.4-2015 — Centerfire Rifle Ammunition (Voluntary Industry Performance Standards)
The American National Standard for centerfire rifle sporting ammunition, published by SAAMI. 375 pages: pressure and velocity performance standards, the test-barrel and test-equipment specifications, and — the part a gunsmith reaches for — the full set of cartridge and chamber drawings plus the HEADSPACE GAUGES section (Section III), which gives the authoritative gauge dimensions for shoulder-, belt-, rim- and mouth-breeching cartridges. For each cartridge the F column's MIN and MAX are the GO and NO-GO gauge lengths, and the M column is the datum diameter the headspace dimension is measured to. NOTE: SAAMI defines no FIELD gauge — that is a commercial addition.
- ANSI/SAAMI Z299.4-2025 — Centerfire Rifle Ammunition (Voluntary Industry Performance Standards)
The current edition of SAAMI's American National Standard for centerfire rifle sporting ammunition (approved 10 February 2025; this file is SAAMI's revision of 27 April 2026). 400 pages: pressure and velocity standards, test-barrel and test-equipment specifications, cartridge and chamber drawings, and the headspace-gauge section. Cited by the 450 Bushmaster dive; the 2015 edition (ansi-saami-z299-4-2015-centerfire-rifle) stays in the Library because older dives quote its page numbers.
- Anwendung der Braunschen Röhre für die Auflösung von Differentialgleichungen auf elektrischem Wege
A three-page German journal article (Archiv für Elektrotechnik, Vol. XXXIII, 1939) by Hans Kleinwächter describing an early analog-computing technique in which a specially constructed Braun tube (CRT) with a resistance-rod collector and inductance-coil differentiator solves ordinary differential equations electrically. The beam position encodes the dependent variable y, an inductance in the anode circuit of an auxiliary tube produces y′, and the Wehnelt-cylinder/deflection arrangement multiplies two variables; circuit schematics for first- and second-order equations are provided and the method is generalized to nth-order cases.
- Anwendungsbeispiele für Analogrechner – Beispiel 6: Beschaltung von Parabelmultiplizier-Netzwerken
Application example 6 in the Telefunken analog-computer application series, dated 22 April 1966, covering parabola multiplier network circuit configurations for the RAT 700, RAT 700/2, RAT 740, RA 741, RA 800, and RA 800 HYBRID machines. The 33-page document provides programming panel wiring diagrams and schematic circuits for multiplication, division, square-root extraction, square root of products and sums of products, multiplication with simultaneous addition, and special multiplier configurations. Each operation is addressed machine-by-machine with both symbolic block diagrams and detailed patch-panel connection drawings.
- Anwendungsbeispiele für Analogrechner — Beispiel 3: Zwei-Massen-System
Application example 3 from TELEFUNKEN's 'Anwendungsbeispiele für Analogrechner' series (15 October 1963), demonstrating analog computer simulation of a coupled two-mass spring-damper system subjected to a step disturbance. The document derives normalized equations of motion, specifies system constants (m₁=20 Kp s²m⁻¹, c₁=1000 Kp m⁻¹, etc.), presents the analog patch diagram, and shows three cases: linear (a), asymmetric damper (b), and piecewise-linear spring (c), with oscilloscope result traces for each case.
- Anwendungsbeispiele für Analogrechner — Beispiel 5: Transformator
A 6-page Telefunken application example (Beispiel 5, October 1963) showing how to simulate a power transformer on an analog computer, including a nonlinear iron-core magnetization characteristic. The document derives normalized differential equations for both ohmic-inductive and ohmic-capacitive loads, presents the analog computing circuit using the implicit (open-amplifier) method, and shows computed waveforms of primary and secondary currents at switch-on.
- Anwendungsbeispiele fur Analogrechner, Beispiel 1: Einige spezielle Kunstschaltungen bei Benutzung des Tischanalogrechners RAT 700
A 7-page German-language application note (dated 15 October 1963) for the Telefunken RAT 700 desktop analog computer, labeled Beispiel 1 (Example 1) in a series of application examples. It presents special Kunstschaltungen (special circuit configurations) including differentiation with a low-pass limiting network, parabolic multiplication to compute Ye²/2 or sign(Ye)·Ye²/2, and square root extraction yielding Ya = Ye/√|Ye|, each illustrated with circuit diagrams and RAT 700 patch-panel wiring diagrams.
- Anwendungsbeispiele für Analogrechner: Beispiel 4 — Erwärmung eines Kabels (Wärmeleitung)
Example 4 in Telefunken's 'Application Examples for Analog Computers' series, dated 15 October 1963. It demonstrates how to simulate radial heat conduction in cylindrical cable insulation on an analog computer: the partial differential equation is reduced to a system of eight coupled ordinary differential equations via finite differences (five radial steps), normalized, mapped to a chain of potentiometer-fed integrators, and solved. Results are presented as time-domain temperature curves at each radial node and as spatial temperature profiles at fixed times.
- AP9101C — Single-Cell Li-ion/Li-Polymer Battery Protection IC Datasheet
- Appendix 2: Drawings — Digital Voltmeter, Model 26.268
This document is Appendix 2 of the EAI Digital Voltmeter Model 26.268 manual, containing the complete set of engineering schematics and wiring diagrams for that instrument. It covers the top-level 26.268 DVM schematic (4 sheets) and wiring (5 sheets), plus individual drawings for all major subassemblies: the 6.463-6 Dual DC Amplifier, 6.736-1 Reference Amplifier, 12.937-5 Miscellaneous Network, 12.1106 Rectifier Network, 12.1654 Conversion Delay Network, 26.116-1 Summing Resistor Network, 26.240 Comparator Amplifier, 26.242 Comparator and Diode Gate Network, 38.032/38.032-1 BCD Counter and Decimal Decoding Matrix, 43.141 Power Supply Regulator, and 44.302-1 Programmer. All drawings are prepared by Electronic Associates, Inc. of Long Branch, New Jersey, in accordance with government electromechanical drafting standards.
- Appendix 3: Model 26,285-1 Digital Voltmeter
Appendix 3 from the EAI 580 Digital Voltmeter manual series, covering the Model 26,285-1 Digital Voltmeter — a variant identical to the Model 26,260-0 except for the addition of two buffer inverter circuit cards. The appendix provides an introduction and specifications (including output connector J3 pin/function assignments for BCD ranges from units to 1000s), a parts list and drawings index for the DVM and the 6,657-0 Buffer Inverter, interior photographs identifying major assemblies, and a full set of schematics and wiring diagrams for both units.
- Apple 1 Mimeo Computer Assembly and Bring Up Guide (rev. 1.1)
Building and bringing up an exact-reproduction Apple-1 board, stage by stage.
- Apple-1 Operation Manual (1976)
The original manual: setting up the board, the Woz Monitor, its examples, the schematic and specifications.
- Arithmetic Operations with the HYDAC Digital Operations System
This bulletin (ALHC 6388-1) describes how the general-purpose logic components of the EAI HYDAC Digital Operations System (DOS) are configured to perform binary arithmetic: half and full adders, half and full subtractors, serial and parallel adder-subtractor units, and serial and serial-parallel binary multipliers. Boolean expressions, truth tables, and DOS patch-panel programs are presented for each circuit, along with the Adder-Subtractor Group building block that reduces patching effort for repetitive operations.
- Arma corta española (Monforte Moreno, ACAMI, 2026)
An academic communication of the Academia de las Ciencias y las Artes Militares (Sección de Prospectiva de la Tecnología Militar), 27 February 2026, surveying the Spanish handgun industry. The Ruby Pistol dive translates it for the Eibar industry around the Ruby.
- Armorers Manual for Maintenance and Repair of Rifle 4,92 mm, ACR — TD 2237, First Draft (Heckler & Koch, 1989)
H&K's first-draft armorer's manual (March 1989) for the 4.92 mm G11 ACR rifle submitted to the US test: technical description, principle of operation including the counter-recoil mechanism, maintenance and repair. The Hyper-Burst Mechanisms dive takes the G11's high-rate burst mechanism from it and reproduces its Figs. 2 and 17–19.
- ASA CX-3 Flight Computer Quick Start Guide
Two-page quick start for ASA's CX-3 electronic flight computer, with its FAA-test statement.
- Assemblée nationale, Question au Gouvernement n° 1108 (1999): GIAT Industries
A National Assembly question of January 1999 to the defence minister, with his answer, on GIAT Industries' strategic plan of 7 July 1998 and the rationalisation of its sites. Used in the MAS FR-F2 dive's research on the maker's decline.
- Assemblée nationale, Rapport d'information n° 3170 (2006): Giat Industries — suivi des mesures sociales d'accompagnement
A National Assembly information report of 20 June 2006 on the social measures accompanying the restructuring of Giat Industries, citing decree 90-582 of 9 July 1990. The MAS FR-F2 dive cites it for the end of small-arms making at Saint-Étienne.
- Assembling the Fragment D on the Antikythera Mechanism: Its Role and Operation in the Draconic Gearing
Mediterranean Archaeology and Archaeometry 22(3), 103–131. Reads fragment D's 63-tooth gear as part of a draconic train.
- Assignment of Serial No. 70,412 'Improvements in Cryptographs' (Friedman & Rowlett to the U.S., 1936; NSA REF ID A39742)
The SIGABA stepping-maze patent application (filed 23 Mar 1936) assigned to the Government for $1 (2 pp)
- AT&T Step-by-Step Equipment Engineering Notes, Bulletin 21.5 (part 1)
Early Bell engineering notes on SxS equipment design and trunking.
- Atari Bug Hunt — Game Manual
XG-1 game for the XE Game System or an XL/XE computer.
- Atari Games Area 51 — Operator's Manual
Optic gun assemblies and calibration.
- Atari Games Maximum Force — 25" Dedicated Game Operation Manual
April 1997 manual: the 'Optical Gun Type' assembly, its lens and maintenance.
- Atari Personal Computer System — Operating System User's Manual and Hardware Manual (C016555, November 1980)
ANTIC's PENH/PENV light-pen registers, the trigger line on controller pin 6, the jack pinout and calibration advice.
- Atari STE Developer Addendum (25 May 1989)
Light gun/pen position registers FF9220/FF9222 and their accuracy by screen mode.
- Atari XE Game System — Owner's Manual (C033514)
Using the XG-1 light gun: 3–5 ft range, port 1.
- ATF FFL Newsletter (c. 1990–91) — MP-83 and MP-22 Pistols Classified as Machineguns
An undated FFL Newsletter (it reports a court decision of 13 September 1990) classing the Holmes MP-83 and MP-22 open-bolt pistols as machineguns because their design features are "similar to weapons identified in ATF Rulings 82-2, 82-8, and 83-5". The STEN dive cites it to show that ATF's position is design by design, not a blanket 1982 ban.
- ATF Firearms Curios or Relics List, January 1972 through April 2025 (ATF P 5300.11)
ATF's consolidated list of every curio-or-relic classification from 1972 to April 2025, including the NFA weapons removed from the Act as collector's items (Section IIIA). Many dives cite it to say whether a gun is C&R-eligible or has been removed from the NFA.
- ATF National Firearms Act Handbook (E-Publication 5320.8, 2009)
ATF's handbook to the National Firearms Act (revised April 2009): definitions, registration and transfer, DEWATs, amnesty periods, importation and the rulings in Appendix B. Several machine-gun and SMG dives quote it for what a private owner may and may not hold, and why an unregistered war trophy cannot now be registered.
- ATF NFA Handbook (2009), Appendix B — Rulings and ATF Articles
Appendix B of ATF's National Firearms Act Handbook, issued as a separate file: the published ATF rulings on NFA classification (auto sears, open-bolt semi-automatics such as Rul. 82-2, 82-8 and 83-5, and others). The MG 42 dive cites Rul. 82-2 from it for why an open-bolt semi-automatic copy is a machine gun; the STEN dive notes that its rulings are reprinted here.
- ATF Ruling 2006-2 — Devices Designed to Increase the Rate of Fire Are Machineguns
ATF's 2006 ruling that a device which, on a single pull of the trigger, starts an automatic firing cycle that continues until the trigger finger is released is a machinegun. Saved with the STEN dive's ATF rulings but not cited in any volume, so it is tagged to the Firearms project only.
- ATF Ruling 80-21 — Residence of Out-of-State College Students
ATF's ruling that an out-of-state college student may establish residence in the state where he lives during the school term. Held because earlier versions of the STEN dive cited a phantom "ATF Ruling 80-21" as a closed-bolt rule; this is the real 80-21, which the dive's correction notes cite.
- ATF Ruling 82-2 — The KG-9 Pistol Is a Machinegun
ATF's 1982 ruling that the open-bolt KG-9 pistol is a machinegun because it is designed to be readily converted to automatic fire. Cited by the STEN, Sterling Mk 7 and MG 42 dives for why an open-bolt semi-automatic copy of a submachine gun or machine gun is itself a machinegun.
- ATF Ruling 82-8 — The SM10 and SM11A1 Pistols and SAC Carbines Are Machineguns
ATF's 1982 ruling that the open-bolt SM10 and SM11A1 pistols and SAC carbines (semi-automatic MAC-type guns) are machineguns. Cited by the STEN and Sterling Mk 7 dives with Rulings 82-2 and 83-5.
- ATF Ruling 83-5 — The YAC STEN MK II Carbine Is a Machinegun
ATF's 1983 ruling that the YAC STEN MK II semi-automatic carbine, an open-bolt design with a fixed firing pin, is a machinegun under the NFA because it is readily restorable to automatic fire. The STEN dive's legal volume rests on it, and the Sterling Mk 7 dive applies it to open-bolt semi-automatic copies.
- Atmel AT91SAM7L128/64 Datasheet
Datasheet for the ARM7TDMI microcontroller that ran the Nut emulator in the 2008 HP 12C.
- Aufbau und Arbeitsweise des Hybrid-Rechners TRICE
A German-language technical article by W. Ameling (EA GmbH Aachen) describing the construction and operation of the TRICE hybrid computer (Transistorized Realtime Incremental Computer), a transistorized incremental digital computer developed by Packard-Bell. The article explains the basic computational units (integrators, adders, multipliers, servo, and analog-digital converters), the programming method for systems of differential equations using incremental arithmetic, and the machine's performance characteristics including operation at up to 100 kHz iteration rate. Published in Elektronische Rechenanlagen, Vol. 4, No. 1, 1962, pp. 28-44.
- Aufbau und Inhaltsbeschreibung des Analogrechners Typ 38500
An 8-page German-language technical description (December 1971) of the construction and board-by-board content of the PEK Electronic Analog Computer Type 38500. Covers the ten plug-in computing boards including potentiometers (38500), two summing amplifier boards (38501/38504), integrators (38503), two multiplier boards (38505/38507), the programming patch field (38506), measured-value display (38508), operating and control board (38509), and the dual power supply unit (36013/A3). The system operates at ±15 V; boards use DIN A3 Eurocard format and fit into a fold-out demonstration housing.
- Ausbildungsausstattung Analogrechner Wirkungsweise Typ 35 957: Geräte und Funktionsbeschreibung, Bedienungsanleitung
Operating instructions and device/functional description for the PEK Electronic Type 35 957 analog computer training kit (1st edition, 1971), prepared by Dr.-Ing. Paul E. Klein. Covers the educational significance of analog computers, component symbols (potentiometer, summing amplifier, integrator, multiplier, divider, comparator, function generator), a structured table of contents for exercises from basic voltage generation through PID controller experiments, and a full parts list of PEK teaching boards and accessories included in the kit.
- Automatic Analog Computer Control by Means of Punched Cards — "CRESSIDA I"
NASA Technical Translation TT F-8843 of EURATOM CETIS Report No. 46 (April 1962), authored by Armand Van Wauve at the Ispra Scientific Information Data Processing Center. Describes the CRESSIDA I project, which automates static digital-analog coupling for EAI PACE 231R analog computers by linking the ADIOS console to a modified IBM 026 card punch, enabling punched-card input/output of analog quantities and automatic coefficient setting via the APACHE II language processed on an IBM 7090. The 28-page report covers system architecture, relay-based control circuits, instructions for IBM 026 operation as an ADIOS I/O unit, and future plans including CRESSIDA II.
- Automatic Electric History
Short history of Strowger, Keith and the Automatic Electric company.
- Automatic Electric Standard Adjustments (compilation, 1940s-50s)
933-page compilation of AE adjustment requirements for relays, Strowger switches, line switches, keys and jacks. The core maintenance reference for a working SxS system.
- Automatic Navigation Computer ASN-7
Sales brochure for the Ford Instrument Company ASN-7 Automatic Navigation Computer, a self-contained airborne dead-reckoning system that continuously displays course, distance, and present position. The ASN-7 accepts inputs of heading, true airspeed, magnetic variation, and wind speed/direction to compute and display geographic coordinates of present position and destination; it supports an alternate stored destination and Doppler radar integration. Weights, dimensions, input/output specifications, and a competitive comparison table are provided, along with descriptions of accessories under development including a Polar Heading Adapter and Automatic Fix Corrector.
- Automatic Projector Calibration with Embedded Light Sensors (MERL TR2004-036)
Gray-code patterns from a projector, read by photodiodes, locate points on a screen: a sensing method for light guns.
- Automatic Telephone Practice (6th ed.)
Early practical text on automatic (Strowger) telephone systems.
- Automatic Telephone Systems, Vol. 1
British treatise on automatic systems (Strowger) circuits and apparatus.
- Automatic Telephone Systems, Vol. 2: Auxiliary Services and Private and Branch Exchanges
Private and branch exchanges in Strowger practice.
- Automatic Telephone Systems; House Telephones; Testing of Telephone Circuits...
ICS course text with early Strowger exchange description.
- Automatic Telephony: A Comprehensive Treatise on Automatic and Semi-Automatic Systems (2nd ed.)
Classic US text on Strowger/AE and other automatic systems, with circuits.
- Automatic World, January 1936 (Vol. 6 No. 2)
Coin-machine trade monthly. Its report on the January 1936 coin machine show (p. 33) covers the launch of Seeburg's Ray-O-Lite Rifle Range. Downsampled to 150 dpi from the 219 MB scan.
- Automáticas eibarresas en la Gran Guerra (Calvó, 2008)
A four-page Spanish article by the Eibar arms historian Juan L. Calvó on the Eibar automatic pistols made for France in the First World War, beginning with the Gabilondo y Urresti Ruby. The Ruby Pistol dive translates it for the contract history and the subcontracting makers.
- B&T Rotex-LMX Kal. 4.6 mm × 30 — Suppressor Data Sheet
B&T's data sheet for the Rotex-LMX suppressor for the MP7 (DS_SD-123198-00-EN). Cited by the HK MP7 dive's suppressor section.
- B&T Suppressors Catalogue 2025
B&T's 2025 English-language suppressor catalogue, with its technical-specification table and company history. The HK Mk23 dive cites it for the current B&T cans that fit the pistol.
- Banana Plug Modules: Plug-in Networks for Comdyna and EAI Analog Computers
A two-page price-list datasheet for Comdyna banana plug modules — self-contained plug-in computing networks compatible with Comdyna analog computers and EAI TR-20/48 and 380/580 analog computers. The sheet lists part numbers 9302 through 9780 covering D/A electronic switches, comparator feedback elements, function switches, coefficient potentiometers, limiters, zero limiters, dead-space networks, absolute-value circuits, two-input summer networks, and patchable diodes, each with specifications and quantity-break pricing (1-3, 4-9, and 10-15 units). Modules patch directly to standard 3/4-inch hole-spacing banana jacks and are offered on a two-week trial basis.
- Bedienungsanleitung zum Elektronischen Analogrechner RA 463/2
Complete operating manual (Bedienungsanleitung) for the Telefunken RA 463/2 fully electronic repetitive analog computer, covering general characteristics, commissioning, calibration procedures for mains devices, display device, and computing units, and detailed instructions for all nine computing operations including multiplication by constant, summation, integration, differentiation, multiplication, division, and arbitrary function generation. The 12-page German-language document includes a worked differential-equation example and repair/warranty information; the machine operates with computation intervals continuously variable between 0.1 and 112 seconds and ±100 V machine units.
- Bedienungsanleitung: Analogrechner EA-22
Operator manual for the GTE transistor-based analog computer EA-22, covering all operating modes (Anfangswert, Rechnen, Halten, Pot), the precision timer ZG-22 with repetitive/iterative/halt computation modes, parallel connection of multiple EA-22 units, and detailed descriptions of each operational unit: integrator-summator (ZG-A/S), double-multiplier summator (PM1-A/B), function-generator double-summator (FG-A/B with 20 diode segments), and double comparator-summator (KE-A/B). Includes procedures for zero-point adjustment, potentiometer setting, selector switch AS-22, and amplifier magazine maintenance.
- Bedienungsanleitung: Schul-Analogrechner Modell EC-1-E
German-language operating manual for the Heathkit EC-1-E Schul-Analogrechner (educational analog computer), a 9-amplifier machine powered from 220 V mains with adjustable repetition frequency (1–60 Hz), 100 V reference voltage, and three initial-condition voltages. The manual covers operational-amplifier theory (summation, integration, diode nonlinearities), the balancing and setup procedure, and step-by-step programming examples including first- and second-order differential equations, spring-mass systems, polynomial simulation, PID controllers, and the bouncing-ball problem.
- Before Super-Computers: NSA and Computer Development (NSA 50th-anniversary almanac, DOCID 3575750)
Short NSA overview from wartime named machines to ATLAS (first program reportedly against VENONA isologs), ABNER (named for Li'l Abner), HARVEST 1962–76 and the Cray-1 (6 pp)
- Bell Laboratories Record, December 1957 (A Modern Crossbar PBX: the 756A)
Overview of the 756A crossbar PBX: capacity, modules, 48 V power, numbering and trunks.
- Bell Laboratories Record, January 1959 (Crossbar Circuitry for a Small PBX)
The 756A's marker, register, junctors and link wiring.
- Bell Laboratories Record, July 1937 (The Crossbar Switch)
Bell's introduction to the crossbar switch: bars, select and hold magnets, fingers and contacts.
- Bell Laboratories Record, June 1938 (The Crossbar Switch in the 755 PBX; The 755 PBX)
The one-switch 755A crossbar PBX: lines on the verticals, links and trunks on the horizontals, relay control with no marker.
- Bell Laboratories Record, June 1963: PBX Consoles (J. H. Coyne)
PBX attendant consoles, including the 756A's early console.
- Bell Laboratories Record, March 1949 (No. 5 Crossbar)
Introduces the No. 5 crossbar system (context for what replaced SxS).
- Bell System Switching Timeline 1878-1975
One-page timeline of switching systems (image).
- Beschreibung des Digitalzusatzes DEX 802
Program information document (July 1971) describing the DEX 802 digital supplement for the Telefunken hybrid analog-digital computing system. Covers the structure and function of the double-width plug-in unit with 24-slot magazine for interchangeable digital logic elements (NAND, NOR, flipflops, counters), technical data (logic levels 0V/+5V-12V, fixed clocks 10 us to 2 s), operating instructions for the DPF digital programming field and DBG control device, and an alphabetical bus and element reference.
- Beschreibung und Bedienungsanleitung des Präzisions-Analogrechners RA 800
German-language description and operating manual for the Telefunken RA 800 Precision Analog Computer. Covers mechanical layout, programming field design with 10 fields of plug-in computing element modules, operating modes (summing, integrating, holding), and specifications for modulation multipliers, parabolic networks, servo multipliers, and potentiometers. The RA 800 features chopper-stabilized amplifiers with less than 0.01% error, a built-in digital voltmeter, and a removable programming field with illuminated pushbutton selection of operating modes.
- Beschreibung und Bedienungsanleitung für den transistorisierten Tischanalogrechner EA 22
Operator manual for the GTE EA 22 transistorized desktop analog computer, covering the machine's constructive design, front- and rear-panel layout, color-coded patch jack assignments, and step-by-step operating procedures. The EA 22 accommodates up to 22 computing amplifiers, 20 coefficient potentiometers, and 10 double-network operational units (integrators, multipliers, function generators) with accuracy classes down to 0.01%. Procedures cover amplifier nulling, potentiometer setting via compensation device or digital voltmeter, function generator adjustment, iterative computing with the precision time base, and memory integrator relay states.
- Best Affine Approximations, Derivatives, and Rates of Change
Section 3.2 of Dan Sloughter's open calculus text 'Difference Equations to Differential Equations' develops the concept of the derivative as the slope of the best affine (linear) approximation to a function at a point, establishing the formal limit definition. The section covers differentiability, the relationship between differentiability and continuity, Leibniz notation, and the interpretation of the derivative as an instantaneous rate of change, illustrated with worked examples including polynomial, radical, and absolute-value functions as well as a projectile-motion problem. A problem set of 20 exercises extends the material to finding derivatives, best affine approximations, tangent lines, and applied rate-of-change problems.
- Beziehung zwischen Produktion und wirtschaftlichen Prozessen — dargestellt an einem Analogie-Rechenmodell für den Analogrechner MEDA 1
A German-language research paper from the Freiberger Forschungshefte (Freiberg Research Papers) series presenting a dynamic analog-computer model of the relationship between production output, procurement, and inventory in an economic system. The paper formulates the model as a set of coupled ordinary differential equations, derives stability conditions, and provides the complete block diagram and patch diagram for implementing the simulation on the East German MEDA 1 small analog computer. Results demonstrate convergent and oscillatory regimes depending on the model's lag-time parameters.
- Block Diagram of Quad DC Amplifier (Hitachi 210/240 Maintenance Manual Excerpt)
A single-page excerpt from the Hitachi 210/240 Maintenance Manual presenting Fig. 5.1.1, a block diagram of the Quad DC Amplifier. The diagram illustrates the major functional sections: Input Protective Circuit, DC Amp Portion (with output current limiter), Chopper Portion, Chopper Amplifier Portion, Chopper Portion Filter, and SI Detector (D Signal). This chopper-stabilized amplifier architecture is typical of precision analog computing elements used in the Hitachi 210/240 system.
- Borchardt Automatic Pistol — DWM English Instruction Manual
The factory's English-language instructions for the Borchardt C-93 as sold by DWM: description, numbered parts, loading, takedown and reassembly with hand-position plates. The source of the factory takedown quoted in the Borchardt C-93 dive.
- Boris Hagelin — career history (NSA Friedman Collection, REF ID A61628)
Typescript history of Boris Hagelin's life and business, from the Nobel oil fields to AB Cryptoteknik and the M-209.
- Bosch Sensortec BMI270 6-Axis Smart Low-Power IMU — Datasheet (BST-BMI270-DS000-08, rev 1.6)
Alternative 6-axis IMU compared in the dive.
- Braverstock on Brewing
- Brewing and Distillation
- British and Foreign Spirits
- British Winemaker and Domestic Brewer
- BSP 030-705-701 197- and 198-Type Switches, Requirements and Adjusting Procedures
Bell adjustment requirements for the WE 197-type step-by-step switch (Bell's Strowger).
- BSP 030-705-703 197- and 198-Type Switches, Contact Springs Requirements and Adjusting
Bell spring requirements for 197/198 switches.
- BSP 030-705-802 197- and 198-Type Switches, Piece-Part Replacement
Bell piece-part replacement procedures for 197/198 switches.
- BSP 550-000-000: Division 550 (755A PBX) Numerical Index (1972)
Index of the Bell System Practices for the 755A PBX.
- BSP 550-001-011: 755A PBX, Equipment Test List (1972)
The routine tests and intervals for 755A equipment.
- BSP 550-550-110: 755A PBX, General Description (issue 1, 1937)
The 755A crossbar PBX: switch, numbering, power, circuit functions, and a local call relay by relay.
- BSP 550-550-210: 755A PBX, Installation (issue 4, 1960)
Installing the 755A PBX; lists its circuit drawings.
- BSP 550-550-230: 755A PBX, Tests and Inspections at Time of Installation
Acceptance tests and inspections for a newly installed 755A.
- BSP 550-550-500: 755A PBX, Alarms, Operation Tests (1952)
Alarm operation tests for the 755A.
- BSP 550-550-590: 755A PBX, Link and Link Allotter Circuits, Operation Tests (1952)
Operation tests for the 755A's links and link allotter.
- BSP 550-550-665: 755A PBX, Trunks, Operation Tests (1938)
Operation tests for the 755A's central-office trunks.
- BSP 551-100-100: 756A PBX Task Oriented Practice, Vol. 1, Installation and Test
Installation, test and routine task lists for a working small crossbar PBX (446 pp.).
- BSP 551-100-101: 756A PBX Task Oriented Practice, Vol. 2, Repair
Trouble indicators, repair and adjustment for the 756A crossbar PBX.
- BSP 551-144-210: 756A PBX, Miscellaneous Equipment (Tie Trunks, Paging)
Tie trunks and other equipment of the 756A; the model for linking the crossbar and step-by-step systems.
- BSP 551-147-210: 756A PBX, Method of Providing Service Options
Stations, trunks, dial-pulse register, night connections and power plant options of the 756A.
- BSP 570-302-400 Rectifiers
BSP 570-302-400, *Rectifiers for Teletypewriter Station Apparatus — Wiring Diagrams*, Issue 1, Dec 1964
- BSP 572-008-201 Installation of TP97301 Filter Unit
BSP 572-008-201, *Installation of TP97301 Filter Unit for Line Relay Contacts of 14 Teletypewriters and Typing Reperforators*, Issue 2, Oct 1957
- Bud Radio 148 Extrusion (Side Rail) Drawings, Sheet Set 2 of 2 — metric
Bud's drawings for the Grand Prix case's side extrusion: 148 assembly, 148-A and the 148-B cross-section, with Chris Davis's metric annotations and CNC note.
- Bud Radio MD-1 "Grand Prix" Case Drawings (1965–74), Sheet Set 1 of 2 — metric
Bud's engineering drawings for the KENBAK-1's case: MD-1 assembly, 1-P rear panel and 1-B top/bottom (20-gauge steel), converted to millimetres by Chris Davis for the PCBWay community case files.
- Bulletin 1026: Strowger P-A-X
AE sales bulletin describing the Strowger private automatic exchange.
- Bulletin 1030: Automatic Telephony as a Career
AE recruiting booklet describing the Strowger system and AE factory.
- Bulletin 141B - Description and Adjustments Models 14 and 20 Transmitter Distributor 1964
Bulletin 141B — Description and Adjustments, Models 14 and 20 Transmitter Distributor (+ two-channel TD, distortion test set)
- Bulletin No 138 - Adjustments Typebar Page Printer Model 15 Bulletin 138 1944
Bulletin No. 138 — Adjustments, Typebar Page Printer, Model 15
- Bulletin No 144 - Description Type Bar Page Printer Model 15 1944
Bulletin No. 144 — Description, Type Bar Page Printer, Model 15
- Bulletin No 172 - Description Typing Reperforator Bulletin 172 1943
Bulletin No. 172 — Description, Typing Reperforator (Model 14)
- Busicom Calculator with Mostek Chips: TCD Treasures Catalogue Entry
Trinity College Dublin's catalogue entry for a Busicom calculator, with Joerg Woerner's notes on the Mostek MK6010 and MK50xx chips: 25 V and 15 V processes, digit times of four clocks and scan cycles of fifteen digit times.
- Buyer's Guide: Telephone Equipment and Supplies — Automatic Electric, Catalog 1900 (Oct 57) (1957)
Complete, 88 pp, OCR. Includes Strowger dial-office pages. The Library's "AE 1957 dial equipment catalogue excerpt" (4 pp) is probably taken from this
- BYTE, January 1981: Hand-Held Computers
Pages from BYTE's hand-held computer issue of January 1981, on the TRS-80 Pocket Computer and its rivals.
- BYTE, January 1981: Sharp PC-1211
BYTE's pages on the Sharp PC-1211 from its January 1981 issue.
- C.I.P. TAB. IV — 7,63 Mauser Cartridge Dimension Sheet
The C.I.P. cartridge and chamber dimension sheet for the 7,63 Mauser (dated 84-06-14, revised 06-09-19), with maximum pressure. The Bergmann 1896/1897 and Borchardt C-93 dives use it for the 7.63 mm cartridge's dimensions against the earlier 7.65 Borchardt.
- C.I.P. TDCC Tab. I — 7,5 × 54 MAS Cartridge Dimension Sheet
The C.I.P. cartridge and chamber sheet for the 7,5 × 54 MAS (dated 07-05-14, revised 11-05-25). The MAS FR-F2 dive quotes its figures for the French service cartridge of the FR-F1.
- C96 Broomhandle Mauser — Disassembly Guide
Step-by-step field-strip and reassembly of the C96 Broomhandle.
- Calendars with Olympiad Display and Eclipse Prediction on the Antikythera Mechanism — Supplementary Information
Supplementary notes to Nature 454, 614–617: Corinthian month names, the games dial, the Saros eclipse glyphs and the games/Callippic gear trains.
- CANDIDE: Overall Plan for Possible Developments of Linkage of the CETIS Analog and Digital Computers
NASA Technical Translation TT F-8591 (January 1964) of the 1963 EURATOM/CETIS report No. 33 by A. Riotte. The paper presents an overall development plan (project CANDIDE) for linking the CETIS analog and digital computers at the Joint Nuclear Research Centre, Ispra, Italy. Two linkage types are addressed: one-directional static linkage placing the analog computer under digital control via the APACHE programming code, and dynamic two-directional linkage using A/D and D/A conversion so the digital computer acts as a real-time function generator. Planned subprojects SATANAS and ATANASE are outlined, along with ancillary studies on automatic scaling, subroutine libraries, and time estimates for each development stage.
- Canon 163 Calculator: Reverse-Engineered Schematic
A 22-page schematic of the Canon 163 Nixie calculator of c. 1968-69, drawn from two working machines: block diagram, timing, the torsional delay line and its amplifiers, TI DTL logic, the 1-2-4-2 serial adder, the multiplexed Nixie display and the +100/+200 V display supplies.
- Canon 163 Calculator: Schematic Appendix
Nine pages of supporting drawings for the Canon 163 schematic: flip-flop forms, timing diagrams, the register and delay-line organisation, state graphs and a worked square root.
- Canon 163 Calculator: Theory of Operation
A 21-page theory of operation written from the reverse-engineered schematic and a logic simulation: the 1 MHz crystal clock, six registers in one delay line, the 1-2-4-2 code, the state machine, number entry, memories, the multiplexed display, and servicing notes (board insertion, forcing states to trace delay-line faults).
- Canon Canola 1200 Logic and Timing Manual
Canon's logic and timing manual for the Canola 1200 Nixie calculator: logic flow, timing diagrams, chip pinouts and schematics.
- Carbine, Machine, STEN, 9 mm, Mk II — General Instructions: Handling, Stripping, Cleaning, Assembling (February 1942)
Nine-page official instruction leaflet issued with the Mk II in February 1942: general description, stripping and assembling, action of the mechanism, care and cleaning, stoppages and immediate action, handling and sighting, and filling the magazine.
- Carbines, Machine, STEN, 9 mm, Mks I, II & III — Illustrated Identification List (COD Weedon, August 1942)
The official illustrated parts identification list for the Mk I, II and III STEN, issued by the Central Ordnance Depot at Weedon in August 1942. Components are arranged by group (butt, body, magazine housing, breech block, trigger mechanism, barrel, magazine, accessories) with drawings and a key showing which Mark each part fits. The nearest thing to an official parts tree in public hands.
- Casio 121-B Calculator: Reverse-Engineered Schematic
A 10-page schematic of the Casio 121-B of 1970: Hitachi HD3100 PMOS chips, the NEC uPD116C Nixie decoder-driver, Toshiba high-voltage drivers and multiplexed Hitachi CD-71 Nixies.
- Casio AL-1000 Calculator: Reverse-Engineered Schematic
A 26-page schematic of Casio's programmable AL-1000 of 1967: discrete DTL, core memory for numbers and program, and multiplexed NEC LD-866 Nixies.
- Casio CQ-1 Computer Quartz Instruction Manual
Instructions for the Casio CQ-1, the first calculator with a built-in clock: clock, alarm, stopwatch and calculator functions.
- Casio fx-100W / fx-115W / fx-570W / fx-991W User's Guide
Casio's multilingual user's guide (English section) for the W series of S-V.P.A.M. scientific calculators with two-line display: modes COMP, CMPLX, SD, REG and BASE-N, integration, TWO WAY POWER, specifications.
- Casio fx-101 Instruction Manual
Instructions for the Casio fx-101 scientific with its green Digitron tube: scientific notation, memory, functions and worked examples.
- Casio fx-102 Instruction Manual
Instructions for the Casio fx-102 scientific calculator, a relative of the fx-101.
- Casio fx-110 Instruction Manual
Instructions for the Casio fx-110 scientific calculator.
- Casio fx-115ES / fx-991ES User's Guide
Casio's user's guide for the fx-115ES and fx-991ES, the top models of the original ES series.
- Casio fx-115ES PLUS / fx-991ES PLUS C (2nd edition) User's Guide
Casio's user's guide for the second edition of the fx-115ES PLUS (US) and fx-991ES PLUS C (Canada): Natural Display, CMPLX, STAT, BASE-N, EQN, MATRIX, TABLE, VECTOR, INEQ, VERIFY and DIST modes, specifications and the authenticity check.
- Casio fx-120 Instruction Manual
Instructions for the Casio fx-120 scientific calculator.
- Casio fx-21 Instruction Manual
Instructions for the Casio fx-21 scientific calculator with its Digitron tube panel (English and Spanish).
- Casio fx-570ES PLUS / fx-991ES PLUS User's Guide
Casio's user's guide for the fx-570ES PLUS and fx-991ES PLUS, the larger ES calculators with equations, complex numbers, matrices, vectors, integration and differentiation, and the calculation ranges and methods.
- Casio fx-570EX / fx-991EX ClassWiz User's Guide
Casio's user's guide for the fx-570EX and fx-991EX ClassWiz, the successors of the ES series.
- Casio fx-7000G Owner's Manual
The 204-page owner's manual for the Casio fx-7000G of 1985, the first graphing calculator: calculations, graphs, statistics and programming.
- Casio FX-702P Brochure (Italian)
An Italian brochure for Casio's FX-702P, its first BASIC pocket computer.
- Casio fx-82ES/83ES/85ES/300ES/350ES User's Guide
Casio's English user's guide for the fx-82ES family (RCA502136-001V01): modes, setup, Natural Display input, fractions, percentages, memories, statistics, tables, specifications and battery replacement.
- Casio fx-82ES/83ES/85ES/300ES/350ES User's Guide Appendix
The appendix to Casio's fx-82ES user's guide (RCA502155-001V01), with the key sequences for its numbered examples.
- Casio fx-82MS/85MS/220PLUS/300MS/350MS User's Guide
Casio's user's guide for the fx-82MS family, the two-line S-V.P.A.M. generation before Natural Display.
- Casio Operation Guide 2888 (DBC-32 Data Bank)
Casio's five-page operation guide (MO0407-EA) for watch module 2888, used in the DBC-32 Multi-Lingual Data Bank: timekeeping in 13 languages, 25-record Data Bank, calculator and currency converter, five alarms, stopwatch, dual time and the LED auto light switch.
- Casio Operation Guide 3228 (DBC-611 Data Bank)
Casio's operation guide (MO1106-EA) for module 3228, the DBC-611 successor to module 2888: Data Bank, calculator, alarms, stopwatch and dual time.
- Casio Personal-8 Calculator: Reverse-Engineered Schematic
Schematic of the Casio Personal-8 of 1975: Hitachi HD3679 single chip driving an NEC LD8120 tube directly, Fuji MPS 0606 converter giving -6, -14, -22 and -29 V and 1.4 V AC filament from 3 V, 1.67 kHz scan.
- Casio personal-mini Instruction Manual
Instructions for the Casio personal-mini with its six-digit Digitron tube: two-part display of twelve-digit results, automatic constant, overflow, batteries and adapter.
- Casio Pocket Computers Brochure
Casio's brochure for its range of pocket computers.
- Casio pocket-mini Instruction Manual
Instructions for the Casio pocket-mini with its multi-Digitron tube panel.
- Casio Watch Operation Guide 3563
A current Casio watch guide (MA2404-EA), cited for Casio's general precautions: water-resistance markings, battery replacement, gaskets, LCD temperature limits and cleaning.
- Catalog 11000, Section Q: Power Equipment — Automatic Electric, Cat. 11000 sec. Q (Sep 69) (1969)
16 pp. Rectifiers, ringing and tone supplies
- Catalog 11000, Section R: Central Office Test Equipment — Automatic Electric, Cat. 11000 sec. R (Sep 65) (1965)
39 pp, image only (no OCR). C-relay test sets, linefinder test stands, switch test sets
- Catalog 11000, Section T: PABX and PBX — Automatic Electric, Cat. 11000 sec. T (Aug 69) (1969)
23 pp, complete section
- Catalog 4014: Strowger Dial Telephones and Telephone Parts
AE telephone and parts catalogue.
- Catalog of Enemy Ordnance Materiel (1945)
The US Army's wartime loose-leaf catalogue of German and Japanese ordnance, with specification sheets and photographs. This scan lacks the machine-gun pages the MG 42 dive looked for; the Mauser HSc dive used it to establish that the HSc is absent (its pistol coverage is the P.38 and the signal pistol).
- Catalog of Telephone Apparatus and Supplies No. 3 — Western Electric (1916)
Complete, 408 pp. The only real catalog found under the photo's running-head title. It lists no Strowger switches; its p. 162 is magneto switchboards
- Cathode Ray Tube Phosphors Of Interest To The Experimenter (rev. 20100226)
A compilation of CRT phosphor P-numbers with colour and persistence.
- CCM (1943–1945) — OP-20-G file, OCR version
CCM correspondence and cycle studies, Dayton–Washington and GCCS links (77 pp., 24 MB) [writer A]
- CDK C1HB Calculator: Reverse-Engineered Schematic
Schematic of the CDK C1HB desk calculator of 1977: a TI TMS1273 driving an Itron FG139A3 tube directly through 100 k pull-downs to -35 V, with a blocking-oscillator supply.
- CE TI-Basic Programming Guide for the TI CE Family of Graphing Calculators (v5.7)
The version 5.7 TI-BASIC programming guide for the TI-84 Plus CE family, after the removal of assembly programs.
- CFA Institute: Mastering Your Calculator for the CFA Exam (BA II Plus and HP 12C)
The CFA Institute's guide for candidates to its two permitted calculators.
- Changing Machines
Postwar SIGROD for military attachés; photos of SIGROD and its rotor basket (2 pp.) [writer A]
- Chronology of Pickett Slide Rule Development
One-page illustrated chart dating Pickett rules c.1945-1975 by alloy, slide/rail interface, slide tension springs, end-brace (stator post) style, cursor bars, lenses and logo style (Styles 0-6). Used to date the N-515-T and any Pickett.
- CIA Information Report — New Soviet 7.62 mm Semi-Automatic Carbine SKS, Submachine Gun, and 7.62 mm Pistol (14 April 1955, CONFIDENTIAL)
A thirteen-page CIA information report distributed 14 April 1955, classified CONFIDENTIAL and declassified in 2013 (CREST CIA-RDP82-00046R000500020007-7), reporting from the Soviet Zone of Austria and including a drawn sketch of the rifle. Two years of better access corrected the 1953 report's errors: this one has the SKS as semi-automatic and charged from a stripper clip through the top. Its real value is the security practice around the weapon and its AMMUNITION. On the range 'each marksman was flanked by a second soldier whose function it was to retrieve all ejected brass with his garrison cap (pilotka)', and every case was counted afterwards — the cartridge was classified, not just the rifle. The gate guard drew one of six obsolete PPSh submachine guns each company retained for occasions when personnel would be seen by Austrians: a cover weapon carried on strength so the real one stayed indoors. The report also names the rifle's manual, which was NOT classified and sat in the company orderly room.
- CIA Information Report — New Type Soviet Submachine Gun and Carbine (29 April 1953, SECRET)
A five-page CIA information report distributed 29 April 1953, classified SECRET / SECURITY INFORMATION and declassified in 2009 (CREST CIA-RDP80-00810A001000900006-5). Source: a member of the Krasnoselskiy Guards, Order of Aleksandr Nevskiy Rifle Regiment. It describes two new Soviet weapons issued alongside the old PPSh — the AK-47 and the SKS — with two hand-drawn memory sketches. NOTE: the report is marked UNEVALUATED and it gets two things about the carbine WRONG, which is exactly why it is worth reading: it says the carbine 'could be fired automatically or could fire single shots' (the SKS is semi-automatic only) and that 'the clip was placed into the magazine from the bottom part of the stock' (it is charged from a stripper clip through the top, over an open bolt). Its account of the SECRECY is first-hand and accurate: the weapons were military secrets issued only to the Leningrad and Far Eastern military districts, and only to troops in settlements away from inhabited localities.
- Circular 1702-E: Relays and switches for industrial use
AE industrial catalogue of telephone-type relays and stepping switches with specs.
- Civil Penalties; Notice of Adjusted Maximum Amounts (CPSC, 86 FR 68244, 1 December 2021)
The $120,000 per violation / $17,150,000 maximum civil penalties.
- Clockwork PicoCalc — Deep Dive Reference
- ClockworkPi CM4 Adapter Board — Schematic
- ClockworkPi Mainboard v3.14 — Schematic
- ClockworkPi Mainboard v3.14 (Rev v5) — Schematic
- ClockworkPi PicoCalc — Assembly Guidelines
- ClockworkPi uConsole — Assembly Guidelines
- Close Range Weapon — From "NBW" to "MP7 A1" (Heckler & Koch presentation, 2 March 2004)
H&K's 70-slide presentation of 2 March 2004 tracing the weapon from the NBW concept to the MP7A1, with a cutaway and the ammunition makers. The HK MP7 dive uses it for the development history.
- Close Range Weapon MP7 A1, Caliber 4.6 mm × 30 — Operators Manual (Heckler & Koch)
H&K's English operator's manual for the MP7A1 (a faxed copy dated 8 August 2011): safety, technical data, handling and operation, field stripping, function check and accessories. The HK MP7 dive's main source for the mechanism and maintenance; the FN P90 dive cites its data.
- Commissione parlamentare d'inchiesta sul rapimento e sulla morte di Aldo Moro — Bollettino, 25 July 2017
The Italian Chamber of Deputies bulletin of 25 July 2017 from the parliamentary inquiry into Aldo Moro's kidnapping and murder (1978), recording the commission's decision to have its consultants examine further the Škorpion used to kill Moro. Cited by the Škorpion vz. 61 dive (p. 212).
- Commodore 64 Programmer's Reference Guide
Control port 1 pin 6 (BUTTON A/LP) and the VIC-II LPX/LPY light-pen latch. Downsampled to 150 dpi.
- Commodore Custom Green Line Operating Instructions (997R, 996R, 994R, 97D, 96D, 94D)
Operating instructions for the Commodore Green Line fluorescent pocket calculators: keys, constants, exchange key, percent, memory and interest examples.
- Commodore VIC-20 Programmer's Reference Guide
'Using a light pen on the VIC': pin 6 / user port pin 7 and registers $9006/$9007.
- Comparing the Difficulty of Factorization and Discrete Logarithm: a 240-digit Experiment (CRYPTO 2020)
RSA-240, DLP-240 and RSA-250 computed with the number field sieve.
- Compensating Polar Planimeters 4236, 4236M, 4237, 4242 & 4242½ (K&E manual, 1949/1957)
K&E's 32-page manual for its fixed-arm and adjustable compensating polar planimeters, including the 4242½: care, setting up, reading the dial, wheel and vernier, tracing, scale factors, indicator diagrams, pole-inside measurement with the neutral circle, accuracy, the testing rule, tracer-arm settings tables and graph, and the calculus theory.
- Compression Molding of Fiber Glass/Epoxy Handguards for the SFLM Advanced Combat Rifle — ARCCB-TR-89017
An Army technical report on moulding handguards for the serial flechette launch mechanism (SFLM) Advanced Combat Rifle; its Fig. 1 shows the rifle. Held in the Hyper-Burst Mechanisms research; the identity of the SFLM rifle with AAI's ACR entry is not established there.
- Computer Mode and Time Scale Control System (EAI 580 Console Manual, Chapter 3)
Chapter 3 of the EAI 580 console manual describes the computer mode and time scale control system, covering the six operating and setup modes (OPERATE, HOLD, INITIAL CONDITION, STATIC TEST, SET POT, PROGRAM PANEL), the 0.12.1607 Control Tray, and the analog timer circuits with four integrator time scales from 0.2 ms to 1.0 sec. The chapter includes theory of operation for the mode selection flip-flop logic, the rep-op timer card, and peripheral control circuits (pen control, chart control, blanking), followed by replaceable parts lists and full schematics for the keyboard panel, control tray cards (0.12.1615, 0.12.1616), rep-op timer card (0.36.0192), mode control card (0.51.0357-1), and time scale rep-op card (0.51.0363-1).
- Computer Power Supply AS1104.2 Instruction Manual
Instruction manual for the Solartron AS1104.2 Computer Power Supply, a stabilised high-tension supply and valve heater supply designed for the Analogue Computing System. Covers performance specifications (output voltages including regulated ±100V and ±200V DC rails), installation and operating instructions, circuit description, maintenance and setting-up procedures, components list, and circuit diagrams with component location illustrations.
- Computing Examples for the Curta Calculating Machine
Contina's worked-examples booklet for the Curta: the four basic operations and the short-cut methods built on them, shown step by step with dial settings. Scanned copy; the text layer is OCR and carries errors. Undated; it covers the Model II, so it postdates that model's introduction.
- Computing Mechanisms and Linkages
Volume 27 of the MIT Radiation Laboratory Series, authored by Antonin Svoboda and edited by Hubert M. James. Covers the mathematical design of mechanical computing mechanisms and linkage computers, including harmonic transformers, three-bar linkages, cams, integrators, resolvers, and bar-linkage combinations. Developed under wartime pressure for practical methods of designing linkage-based analog computers; originally published by McGraw-Hill in 1948.
- Conserve O Gram 1/12: How to Select Gloves (2010)
Which gloves to wear when handling collection objects, and when.
- Conserve O Gram 18/2: Safe Plastics and Fabrics for Exhibit and Storage (2004)
Which plastics, foams and fabrics are safe to store objects in, and which give off harmful vapours.
- Conserve O Gram 3/4: Mold — Prevention of Growth in Museum Collections (2007)
Humidity, temperature and housekeeping to keep mould off stored objects.
- Considering a VHF/UHF Antenna for Your Home?
- Constant and Linear Functions
A three-page lecture note introducing constant functions f(x) = c and linear functions f(x) = mx + b, with graphical interpretation of parameters. The document covers how changing the slope m and y-intercept b affect the graph, and derives the formula for slope from two known function values, worked through with numerical examples.
- Continuous Data Analysis with Analog Computers Using Statistical and Regression Techniques
This EAI bulletin (ALAC 62023) demonstrates how fundamental statistical parameters — mean, variance, autocorrelation, cross-correlation, Fourier transform, and power spectrum — can be computed continuously from analog signals using the Exponentially Mapped Past (EMP) method and simple first-order filter circuits. The EMP approach eliminates the need to reset integrators by weighting recent data more heavily, enabling truly continuous on-line estimation. Linear and higher-order regression analysis is also developed, with a worked example applying EMP mean and variance to automated temperature control in the LD steel-making process.
- Cooling Cups and Dainty Drinks a Collection of Recipes for Cups and Other Compounded Drinks
- ČOS 130511 — Příručka pro zkoušení a kontrolu malorážových nábojů (STANAG 4823 / AEP-97(A)), 2023
The Czech defence standard implementing NATO's manual of proof and inspection of small-calibre ammunition (STANAG 4823 / AEP-97(A)), Prague 2023: test procedures, test barrels and the weapons nominated for testing. The HK MP7 dive translates Annex 10-A1, which names the MP7 as the weapon used to test 4.6 × 30 ammunition, and the 5.7 mm test barrel in Annex 6-A.
- ČOS 130512 — Požadavky na zaměnitelné náboje 4,6 × 30 mm (STANAG 4820 / AOP-4820(A)), 2025
The Czech defence standard implementing STANAG 4820 Ed. 1 / AOP-4820(A), the NATO requirements for interchangeable 4.6 × 30 mm ammunition (Prague 2025). The HK MP7 dive translates sections 7.1–7.19 and Annex A for the cartridge's standardised specification.
- Cosel LCA75S 75 W Power Supply — Product Details
The 24 V supply rating in Sega cabinets (a product-page capture).
- Cottage Economy Containing Information Relative to the Brewing of Beer, etc.
- Crossbar Dial System: Illustrations of Crossbar Equipment — Bell System (training) (1938)
24 pp (6 MB copy; the 42 MB scan was skipped). Crossbar switches of the 755A's era
- Crossbar Systems (Peter Walker, Telecommunications Heritage Group)
A clear introduction to crossbar switching and its history, including Ericsson and UK systems and interworking with Strowger.
- CSI Computer System/Remote Interface Unit Acceptance Test Results
NASA Technical Memorandum 104218 (March 1992) reporting acceptance test results for the Control/Structures Interaction (CSI) Computer System (CCS) and Remote Interface Unit (RIU) installed at the Space Structures Research Laboratory, Langley Research Center. The RIU provides 16 analog input channels through a 12-bit A/D converter and 8 output channels through 12-bit D/A converters, with analog anti-aliasing filters and a DSP board for digital filtering; the CCS uses spaceflight-qualified 1750A CPU and array processor hardware communicating over a MIL-STD 1553B bus. Test results cover hardware acceptance, software/control computation verification, open- and closed-loop tests, digital filtering, and standalone RIU operation.
- CubeSatSim Ground Station Quick Start Guide
- CubeSatSim Main Board Schematic
- Culture of the Grape
- Current Publications (Circular 3013-K) — Automatic Electric (1963)
46 pp. AE's own index of bulletins, circulars and catalogs. Use it as a want-list (stepping switch circulars 1698-K, 1641-D; TB 961-474, 961-880)
- Curta Calculating Techniques
A loose-leaf set of Curta methods issued free by the British agent, Automatic Business Machines Ltd of London: general techniques, commercial work in sterling, engineering examples, and mathematical procedures such as roots, polynomials and series, with numbered Curta tables. Scanned copy; the text layer is OCR and carries errors. Undated; it covers both models and works in pre-decimal sterling, so it predates February 1971.
- Curta Computing Methods — Business and Statistical Examples, with Five-Place Logarithm Tables
A Curta calculating handbook that opens with a product description and goes on to business methods, statistics on grouped data, and five-place logarithm tables. The scan has a blank cover and no title page, so the title given here is descriptive. The text layer is OCR and carries errors. Undated.
- D. W. Seiler, "U.S. Naval Code and Signal Laboratory — History of" (REF ID A40422)
Navy lab history: ECM Mark I and II, the Navy's 1932 rotor-stepping claim, CCM (CSP 1600/1700/1800), CSP 2900 production figures (7 pp.) [writer A]
- Das EAI 180 Analog/Hybrid-Rechensystem
German-language product brochure for the EAI-180 analog/hybrid computer, a compact desktop-class machine intended for education and research. The brochure details the system's analog section (12 summers/integrators, 8 potentiometers, multiplier, diode function generators) and logic section (AND/NAND gates, flip-flops, BCD and binary counters), along with key specifications including 10 V reference voltage, 100 kHz amplifier bandwidth, and ±0.25% component precision. Applications, available output peripherals, and the broader EAI product lineup are also described.
- Das Hybride Rechnersystem HRS 900
A 1968 technical journal article by Ralf Schwarz, published in Techn. Mitt. AEG-TELEFUNKEN (3rd supplement, Datenverarbeitung), describing the AEG-TELEFUNKEN HRS 900 hybrid computer system. The system combines the RA 770 precision analog computer (with sub-computers RA 775 and RA 776), the hybrid coupling unit HKW 900, and the CII/SDS-licensed 90-40 digital computer (24-bit, 6 MHz, up to 32K words). The article explains the rationale for hybrid computing — filling the speed gap of digital computers in solving differential equations — and details the architecture of each subsystem including the digital programming field, timing circuits, servo potentiometers, and data-transfer mechanisms.
- Das Kentern von Schiffen in unregelmässiger längslaufender See
Doctoral dissertation published as Institut für Schiffbau Hamburg Bericht Nr. 249 (December 1968) by Sigismund Kastner, presenting a statistical-computational method for analyzing ship capsizing in irregular longitudinal seas. The nonlinear equation of rolling motion is solved using an analog computer, which the author justifies at length (Chapter 6) for its ability to handle nonlinear righting-lever curves directly, simulate oscillating systems without iteration, and dramatically compress computation time versus digital methods. Results include statistical distributions of time-to-capsize as a function of ship parameters such as metacentric height, damping, freeboard, and speed.
- Dayton Audio TT25-8 / TT25-16 PUCK Tactile Transducer Mini Bass Shaker — User Manual
Mounting and drive for a small tactile transducer.
- De La Biere - Sa Composition Chimique, Sa Fabrication
- DE Patent 194,527: Rechenmaschine (C. Hamann, the Gauss)
The modified form of Hamann's round calculating machine, the Gauss, with its setting mechanism arranged radially around a central axis. German twin of US 832,666.
- DE Patent 209,817: Rechenmaschine (C. Hamann, the proportional lever)
Hamann's proportional lever, filed 1906 and published 1909, the mechanism of the Mercedes-Euklid. German twin of US 1,011,617.
- DE Patent 287,770: Rechenmaschine (C. Hamann, Mercedes-Euklid automatic multiplication and division)
Hamann's patent of 1914–15 that gave the Mercedes-Euklid automatic multiplication and division.
- DE Patent 367,726: Rechenmaschine (Deutsche Telephonwerke, the switching latch)
The first switching-latch patent, filed 24 October 1920 and published 25 January 1923: gear wheels engaged by a latch for a number of teeth set by a stationary disk, instead of pinwheels, with the tens carry made by the drum itself.
- DE Patent 384,150: Rechenmaschine (Deutsche Telephonwerke, one wheel per place)
Filed 24 February 1923: the one-wheel-per-place switching latch, with internal and external teeth on each wheel, the fixed disk and settable segment that form the latch's track, anti-overrun locks and the setting indicator.
- DE Patent 432,435: Rechenmaschine (Deutsche Telephonwerke, automatic division)
Filed 19 December 1924: automatic division with the crank turning one way for every operation, by a reversing gear and a half-step carriage movement. German twin of US 1,788,192.
- DE Patent 443,479: Rechenmaschine (Deutsche Telephonwerke, reversible revolutions counter)
Filed 4 March 1926: the reversible revolutions counter, with the counter lever's + and − positions holding the two-armed counting finger on one side or the other.
- DE Patent 468,275: Rechenmaschine (Deutsche Telephonwerke, counter tens carry)
Filed 4 March 1926: the tens carry for the revolutions counter, the change from the Manus A to the B.
- DE Patent 748,500: Rechenmaschine (C. Hamann, back-transfer)
Hamann's 1940 back-transfer patent, carrying a result back into the setting levers.
- DE Patent 88,223: Führung der Mess- oder Zählrolle an Instrumenten (C. Hamann, planimeter)
Hamann's patent of 11 June 1895, from his instrument workshop in Friedenau, Berlin: a guide for the measuring wheel of planimeters and integrators, using an isosceles slider-crank in place of the Amsler polar or Wetli linear mechanisms.
- DE Patent 919,787: Rechenmaschine (C. Hamann, back-transfer of the Manus R)
Christel Hamann's last major patent, filed 29 October 1949: the back-transfer device of the Manus R.
- Decoding the Ancient Greek Astronomical Calculator Known as the Antikythera Mechanism
Nature 444, 587–591. The CT and surface-imaging study that confirmed the pin-and-slot lunar anomaly and the Saros spiral and doubled the readable text.
- DeepVNA 101 / NanoVNA-F Quick Start Guide (Firmware 1.0.4)
- DeepVNA 101 / NanoVNA-F Quick Start Guide (Firmware 1.0.5)
- Demonstrations-Analogrechner (DIY Miniatur-Analogrechner)
A 9-page German technical description by F. Vogel (2009) of a self-built miniature demonstration analog computer housed in a 188×120×77 mm aluminum enclosure. The machine uses BiFET op-amps with ±10 V machine units and provides 2 integrators, 3 summers, an open amplifier/inverter, 4 ten-turn coefficient potentiometers, a translinear multiplier unit (multiply, divide, square, square-root to ≤0.3% error), and a diode function generator for sine. Auxiliary features include a triangle-wave generator (1.5–75 Hz), 12-position address selector, overload indicator, and ±15 V DC/DC supply powered from a 9 V external adapter.
- Demonstrations-Analogrechner mit Röhren
An 8-page German technical description (dated 21 August 2010) by F. Vogel of a small home-built vacuum-tube demonstration analog computer. The machine uses 10 tubes (4× 6U8, 3× EAA91, 3× OA2), operates at ±50 V machine unit with +300/−150 V supplies, and provides four computing amplifiers (two integrators/summers, one summer, one open amplifier/inverter), three coefficient potentiometers, a piecewise-linear diode function generator for y = −x², two free diodes, reference voltage sources, and a panel meter. Circuit design for the amplifiers is derived from the Heath EC-1 educational analog computer.
- Demonstrationsbeispiel Nr. 5: Ball im Kasten
A 9-page AEG-Telefunken application note presenting Demonstration Example No. 5, which simulates a 2D elastic ball bouncing inside a box under gravity, damping, and elastic wall forces on an analog computer. The document covers the mathematical formulation of motion in x- and y-directions, analog circuit diagrams for four machine variants (RAT 700/RA 741/RA 742, RA 770, and RA 800 HYBRID), and a complete potentiometer list with coefficient values and machine-specific pot numbers. A sine-cosine circle generator is used to display the ball as a moving dot on an oscilloscope in repetitive-run mode with a ~30-second period.
- Demonstrationsbeispiele fur Analogrechner RAT 740 — Beispiel 2: Einfache Darstellung einer Planetenbahn
A short German-language application note (3 pages, dated 1 November 1966) from Telefunken's Analog Computer Department, presenting Example 2 in a series of demonstration programs for the RAT 740 analog computer. The document describes a simplified simulation of planetary orbital motion using Kepler's laws: an elliptical orbit is generated via sine-cosine function generators and multipliers, with the orbital eccentricity and semi-axis adjustable via potentiometers, and the result displayed on an oscilloscope as a Lissajous figure. Page 3 contains the full patching/wiring diagram for the RAT 740 implementing this circuit.
- Dempa Shimbun, 21 July 1967: Ise to Mass-Produce the Digitron (with English translation)
A Japanese trade-paper report that Ise Electronics would soon mass-produce its new numeric display tube, the 'Digitron', developed with Hayakawa Electric and driven at only 25 V, with an English translation.
- Department of the Treasury Study on the Sporting Suitability of Modified Semiautomatic Assault Rifles (ATF, 1998) — excerpts
Four sections of the April 1998 Treasury study that led to the ban on importing modified semi-automatic rifles: the Executive Summary, "Defining the Type of Weapon", the Determination and Exhibit 2, "Study Rifle Models", which lists the PSG1 and MSG90 among the H&K variants. Cited by the HK PSG1 and Steyr AUG dives for the 1989 and 1998 import decisions.
- Der Analogrechner
Second edition (February 1982) of a comprehensive German-language programming and applications manual for the Leybold-Heraeus analog computer. Written by Dr. Martin Hund, the book provides 150 program examples drawn from mathematics, control engineering (Regelungstechnik), and physics, covering basic operational-amplifier circuits, multiplier configurations, diode function generators, ODE solvers, and physical simulations (kinematics, ballistics, oscillations, Schrodinger equation). Includes detailed instructions for amplitude and time scaling, calibration, recorder/oscilloscope recording, and use of the programmable switch accessory (576 07).
- Der Analogrechner als Lehr- und Übungsgerät in der Regelungstechnik
A 20-page German-language lab manual and demonstration proposal (PEK document A 1362, January 1972) based on a lecture by Dipl.-Ing. G. Jarbe, showing how the analog computer can serve as a teaching and practice tool in control engineering. The document presents the simulation of a second-order mechanical/electrical oscillatory system using integrators and RC networks, then demonstrates closed-loop control behavior with P- and PD-controllers applied to the same plant, illustrating the effects of varying gain and damping. Numerous oscilloscope-trace diagrams show step responses for different controller parameter settings.
- Der Einfluss internationaler Entwicklung auf die Arbeitsfelder der Polizei (ASPiBGS vol. 7, 2001), incl. Pieper on police firearms
Volume 7 of Arbeiten zu Studium und Praxis im Bundesgrenzschutz (Lübeck, 2001). The HK PSG1 dive cites Gernot Pieper's chapter on current trends in police firearms (pp. 36–39) for German federal police use of the PSG1.
- Der elektronische Analogrechner und seine Verwendung in der Industrie
A 13-page lecture summary by AEG engineer W. Ammon covering the history, structure, and programming of electronic analog computers, with practical application examples including electric braking of a field-controlled DC motor, synchronous generator voltage control, nuclear reactor dynamics, and cyclotron particle trajectories. The document explains normalization and time transformation techniques for scaling differential equations to machine units. It concludes with a comparative table of analog versus digital computer characteristics, noting 1–5% solution accuracy and the analog computer's superiority for solving ordinary differential equations in real time.
- Der logarithmische Rechenschieber und sein Gebrauch
Instruction booklet written by Prof. Ernst Hammer of the Stuttgart Technische Hochschule for Albert Nestler's rules (the preface says Nestler wanted a proper manual to accompany the instruments it supplied to Stuttgart students). Pre-dates the Rietz layout; the ancestor of Nestler's later manual of the same title.
- Der logarithmische Rechenschieber und sein Gebrauch (3rd, enlarged edition)
Nestler's own general instruction book for its rules. § 23–25 describe the System Rietz No. 23 (scales O1/O2 = A/B, U1/U2 = D/C, C = cube scale K, R = reciprocal, L, slide reverse S, S & t, T; the 1:25 map scale and millimetre scales); §§ 92–93 give the Rietz sine and small-angle procedures, including reading sines through the cut-out in the back of the stock. No model-specific 23 R leaflet was found online; this is the closest Nestler-authored manual.
- Der Transistorschalter im analogen Rechenkreis
A 6-page German-language technical article (Elektronische Rechenanlagen, 1966) by E.V. Gilles and H. Schuchmann of the Rechenmaschinen-Laboratorium at Technische Hochschule Stuttgart. The paper analyzes transistor switches (Transistorschalter) used in analog computing networks for solving partial differential equations iteratively, covering switching requirements, transistor parameters (saturation voltage, leakage current, transition frequency fT), and a practical complementary emitter-follower circuit design. Measured results and a comparison table of key switch parameters are provided.
- Derickson et al. — The NanoVNA Vector Network Analyzer (ASEE Paper)
- Description and Principles of Operation Model 28 Typing Reperforator Sets Teletype Bulletin 246B 1964
KTR/ROTR sets, LPR unit, tape and printed-character specs
- Description of Ground Position Indicator Type A-1
This document describes the Ford Instrument Company Ground Position Indicator (GPI) Type A-1, a four-unit airborne system prepared for the U.S. Air Force that continuously computes and displays present latitude and longitude of an aircraft in flight. The system weighs approximately 45 pounds (exclusive of cables), operates from 115 V 400-cycle and 28 V DC power, accepts true airspeed, compass heading, wind direction, wind force, and magnetic variation inputs, and achieves a maximum total air-position error of about 1.5% of computed nautical miles traveled. The document covers operating principles, component descriptions (Preset Control Box, Computer Unit, Amplifier Unit, Ground Position Indicator panel), dimensional drawings, and the trigonometric geometry underlying the latitude/longitude integration.
- Description of Operation of No 15 Teletypewriter Bell System Practices Section AB84 139 1941
Description of Operation of No. 15 Teletypewriter
- Description of Operation of No 15 Teletypewriter Bell System Practices Section P70 013 1951
Description of Operation of No. 15 Teletypewriter
- Design and Analysis of an Analog Computer: From Concept to Final System
A 23-page student engineering paper documenting the design, construction, and analysis of a small analog computer built around operational amplifier circuits. Covers summation amplifiers, integrators, and multipliers as core building blocks, then demonstrates the system solving differential equations, and concludes with observations on the practical viability of large-scale analog computation.
- Design and Develop a Simplified Serial Flechette Rifle — AAI Final Report (1974)
AAI Corporation's final report of May 1974 under contract DAAF03-72-C-0172 on a simplified serial flechette rifle. The Hyper-Burst Mechanisms dive cites it for the AAI line between the SPIW and the ACR.
- Design and Performance of Magnets in the Automatic Telephone
Thesis on the electromagnets of Strowger automatic switches.
- Design and Use of an Electronic Sieve (thesis, University of Manitoba)
Thesis on the UMSU electronic sieve built at the University of Manitoba.
- Design of an Analog Computer
An Engineering Case Library case study (ECL 47) prepared at Stanford University documenting the design and product development of the Systron-Donner 10/20 analog computer. Written by Dick Dunlap, a product designer at Systron-Donner's Electronic Instrumentation division, the case traces the project from preliminary design in early 1963 through prototyping, pilot production, and the challenges of transitioning to full manufacture, covering design decisions, modular architecture, and cost-engineering trade-offs for a small, easily-portable computer aimed at the educational and light industrial markets.
- Designer's Manual for Circuit Design by Analog/Digital Techniques
A designer's manual from Tulane University's Department of Electrical Engineering covering hybrid analog/digital computer techniques for electronic circuit design, dated July 1970. Topics include hardware requirements for hybrid systems, recommended analytical methods (indirect analog simulation, nonlinear semiconductor device modeling, function generation), and representative design examples using the NASAP (Network Analysis System Applications Program) software. The manual demonstrates circuit design workflows using the Tulane hybrid computer facility comprising EAI analog computers and a Univac digital computer.
- Detailed Programming of the Digi-Comp I Experiments
E.S.R.'s supplementary booklet: Boolean algebra and detailed programming of the Digi-Comp I experiments.
- Determination of Rate, Area, and Distribution of Impingement of Waterdrops on Various Airfoils from Trajectories Obtained on the Differential Analyzer
NACA Research Memorandum (RM No. 9A05, February 1949) in which University of California researchers use a differential analyzer to solve the differential equations of waterdrop motion around Joukowski airfoils. Trajectories are computed for three airfoil/angle-of-attack cases, yielding the rate, area, and distribution of waterdrop impingement as functions of two dimensionless moduli; results are compared with impingement data for cylinders. The work demonstrates the differential analyzer as a practical tool for aeronautical icing calculations otherwise requiring laborious numerical integration.
- Deutscher Bundestag Drucksache 10/1721 (1984) — Kleine Anfrage: Kleinwaffenexporte
A Green parliamentary question of 5 July 1984 on West German small-arms exports, including whether the federally funded H&K G11 should see the G3's worldwide spread. Held with the Hyper-Burst Mechanisms dive's Bundestag sources; not cited in its volumes.
- Deutscher Bundestag Drucksache 11/6920 (1990) — Kleine Anfrage: Neuartige Gewehrsysteme und hülsenlose Munition (G 11)
A parliamentary question of 11 April 1990 on the development and introduction of new rifle systems and caseless ammunition (the G11). The Hyper-Burst Mechanisms dive cites it with the government's answer, Drucksache 11/7055.
- Deutscher Bundestag Drucksache 11/7055 (1990) — Antwort der Bundesregierung on the G 11
The federal government's answer of 3 May 1990 to Drucksache 11/6920 on the G11 and caseless ammunition, including the US purchase of G11 caseless technology for its ACR version. The Hyper-Burst Mechanisms dive quotes it on the G11's development and the US connection.
- Deutscher Bundestag Drucksache 12/4956 (1993) — Kleine Anfrage: Beschaffungsmaßnahmen für die Bundeswehr im Handfeuerwaffen- und Ausrüstungsbereich
An SPD parliamentary question of 13 May 1993 on Bundeswehr small-arms procurement, asking how many G11s and derived caseless weapons H&K, Royal Ordnance, the Bundeswehr and others held and whether series production was still planned. Cited by the Hyper-Burst Mechanisms dive.
- Deutscher Bundestag Drucksache 12/5240 (1993) — Antwort der Bundesregierung on small-arms procurement
The federal government's answer of 22 June 1993 to Drucksache 12/4956: the questions could not be answered openly "aus Geheimschutzgründen" and a classified reply went to the SPD's security spokesman. Cited by the Hyper-Burst Mechanisms dive.
- Development of New Methods and Applications of Analog Computation: I - An Experimental Electronic Generalized Integrator; II - Nonstationary Noise for Monte Carlo Studies
Quarterly progress report (September–December 1961) for NASA Contract NAS8-2473, covering two research tasks at the Georgia Tech Analog Computer Laboratory. Part I describes the design and construction of an all-electronic Generalized Integrator capable of integrating analog voltage signals with respect to arbitrary variables, including circuit diagrams for threshold detectors and sampling gates. Part II analyzes techniques for generating nonstationary noise voltages for use in analog-computer Monte Carlo studies, with particular focus on nonstationary shaping of Gaussian band-limited white noise using variable and separated linear networks.
- Dialmaster PAX (brochure) — Stromberg-Carlson (1960)
6 pp
- Die Bayerische Bierbrauerei
- Die Beirbrauerei, die Branntweinbrennerei und die Liqueurfabrication
- Die Bierbrauerie
- Die Differentialgleichung und ihre Lösung mit den Operationsverstärkern; Grundlagen einfacher Regeleinrichtungen
A January 1972 PEK Electronic application note (document numbers L 1112 and L 2310) covering two related topics in 18 pages. The first part (L 1112) explains how to solve ordinary differential equations using op-amp integrator circuits, covering single and double integration, differentiation, time transformation, and a worked RL-circuit simulation example. The second part (L 2310) introduces the fundamentals of simple electronic controllers — P, I, PI, and D types — realized with op-amps, including step-response waveforms and transfer functions.
- Die Funktionsgleichungen des digitalen Integrators
German-language technical article by W. Zoberbier (1968) presenting the characteristic equations of the digital integrator, the fundamental component of the digital differential analyzer (DDA). The paper derives the operational equations governing the Y-register and Z-register modes, analyzes register boundary conditions and overflow handling, and provides synthesis rules for the critical circuit structure around the digital integrator. Applications to general-purpose computer implementation for rapid simulation are discussed.
- Die Klassifizierung mechanischer Rechenmaschinen, Teil 3: Schaltwerksprinzipien
Haertel's classification of the actuating mechanisms of mechanical calculators (3rd ed., in German): stepped drum, pinwheel, proportional lever, switching latch and the rest, crediting Christel Hamann with the switching latch.
- Die Lösung und Darstellung von partiellen Differentialgleichungen auf dem elektronischen Analogrechner
German-language article from the 1962 series 'Elektronische Datenverarbeitung — Fachberichte über programmgesteuerte Maschinen und ihre Anwendung' (Heft 5/1962) addressing the solution and display of partial differential equations on electronic analog computers. Covers the method-of-lines finite-difference discretization approach for parabolic (heat conduction) and hyperbolic (wave equation) PDEs, the Laplace transformation programming method, and oscilloscope display techniques including quasi-3D surface plots for visualizing the solution surface u(x,t). Practical circuit diagrams and worked numerical examples are included.
- Die Planimeter: deren Theorie, Praxis und Geschichte (Trunk, 1865)
A German history and theory of the planimeters known by 1865, from Hermann and Oppikofer to Amsler.
- Difference Equations to Differential Equations — Section 1.1: Calculus: Areas And Tangents
Section 1.1 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations', introducing the two fundamental problems of calculus — computing areas and finding tangent lines — through the method of sequences and limits. The section uses inscribed regular polygons to approximate the area of a unit circle (arriving at pi) and secant-line slopes to approximate the tangent to the parabola y = x² at (1, 1), demonstrating that both problems reduce to evaluating limits of sequences. Eight problem sets reinforce the concepts with additional curves, polygon side counts, and numerical experiments.
- Difference Equations to Differential Equations — Section 1.2: Sequences
Section 1.2 of Dan Sloughter's open calculus text introduces sequences and their limits, developing the formal epsilon-N definition of convergence with worked examples. The section covers limit laws (scalar multiples, sums, products, quotients, and rational powers), criteria for divergence to infinity, and the Monotone Sequence Theorem with illustrative problems. Eighteen pages of theory and exercises make this a self-contained treatment of sequence convergence for a first calculus course.
- Difference Equations to Differential Equations — Section 1.4: Difference Equations
Section 1.4 of Dan Sloughter's open calculus textbook introduces first-order difference equations, covering both the pure geometric form xn+1 = αxn and the general first-order linear form xn+1 = αxn + β. Applications include population growth, radioactive decay half-life calculation, and Newton's law of cooling, with explicit closed-form solutions derived and graphically illustrated. The section closes with sixteen exercises ranging from computing sequence terms to modeling the Fibonacci sequence and two-dimensional heat distribution.
- Difference Equations to Differential Equations — Section 1.5: Nonlinear Difference Equations
Section 1.5 of Dan Sloughter's open calculus textbook introduces nonlinear difference equations through the discrete logistic (inhibited growth) model, contrasting it with the linear uninhibited growth model. The section analyzes convergence behavior as the growth-rate parameter varies: convergence to the carrying capacity M for 0 < alpha <= 2, period-2 and period-4 limiting cycles for larger alpha values, and chaotic behavior near alpha = 2.95. Eight exercises reinforce the concepts using population-ecology scenarios and discrete dynamical systems.
- Difference Equations to Differential Equations — Section 2.2: Trigonometric Functions
Section 2.2 of Dan Sloughter's open calculus text introduces trigonometric functions from right-triangle and unit-circle definitions, then develops amplitude, period, and phase-angle properties of sine and cosine. The section connects periodic functions to natural phenomena such as pendulum motion and sound waves, and closes with a brief introduction to Fourier series as sums of sine and cosine terms.
- Difference Equations to Differential Equations — Section 2.4: Continuous Functions
Section 2.4 of Dan Sloughter's open calculus text covers the definition and properties of continuous functions, including continuity at a point, one-sided continuity, and continuity on open and closed intervals. The section proves continuity of polynomials, rational functions, algebraic functions, and trigonometric functions, and establishes that compositions of continuous functions are continuous. Worked examples and problem sets illustrate removable discontinuities and piecewise-defined functions.
- Difference Equations to Differential Equations — Section 3.6: Newton's Method
Section 3.6 of Dan Sloughter's open calculus textbook presents Newton's method as an iterative root-finding algorithm for equations of the form f(x) = 0. The section derives the recurrence relation x_{n+1} = x_n - f(x_n)/f'(x_n) from best affine (tangent-line) approximations and contrasts the method's speed with the bisection algorithm. Convergence conditions, failure cases (divergence, zero derivative), and worked examples including cos(x) = x and square-root approximation are covered, with problem sets extending to cube and seventh roots.
- Difference Equations to Differential Equations — Section 3.8: Finding Maximum and Minimum Values
Section 3.8 of Dan Sloughter's open calculus textbook covers techniques for finding maximum and minimum values of continuous functions on both closed and open intervals. The section introduces critical points, singular points, the first derivative test, and the second derivative test for local extrema, illustrated with worked examples including trigonometric optimization, maximum likelihood estimation, and a cylindrical can surface-area minimization problem. A problem set of 22 exercises reinforces these techniques.
- Difference Equations to Differential Equations — Section 4.1: The Definite Integral
Section 4.1 of Dan Sloughter's open calculus textbook introduces the definite integral via the quadrature problem — finding the area of a plane region bounded above by a continuous function and below by an interval on the x-axis. The section develops the formal definition using upper and lower Darboux sums, establishes integrability of continuous and piecewise-continuous functions, introduces left-hand and right-hand Riemann sum approximations with worked numerical examples, and covers linearity, additivity, and geometric sign conventions for the definite integral. Practice problems span approximation, geometric interpretation, and proof exercises.
- Difference Equations to Differential Equations — Section 4.4: Using the Fundamental Theorem
Section 4.4 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations' presents the use of the Fundamental Theorem of Integral Calculus to evaluate definite integrals by finding antiderivatives. The section introduces indefinite integrals (general antiderivatives), standard integration formulas for polynomial and trigonometric functions, linearity properties, and the technique of integration by substitution (reversing the chain rule). Worked examples cover polynomial, trigonometric, and composite-function integrands for both indefinite and definite integrals, followed by a comprehensive problem set.
- Difference Equations to Differential Equations — Section 4.6: Improper Integrals
Section 4.6 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations' covers the theory of improper integrals, extending the definite integral to unbounded intervals and functions with infinite discontinuities. The section develops formal definitions, convergence and divergence criteria, comparison propositions (including absolute convergence), and the Cauchy principal value, illustrated throughout with worked examples and accompanied by a problem set.
- Difference Equations to Differential Equations — Section 6.1: The Exponential Function
This 12-page chapter section from Dan Sloughter's open calculus text defines the exponential function exp(x) via its power series and derives its key properties: self-differentiation, the addition law exp(a+b)=exp(a)exp(b), and the identification exp(x)=e^x for all real x including irrationals. Differentiation and integration techniques are developed through worked examples, and the section closes with an uninhibited-population-growth application modeled by the differential equation x'(t)=λx(t) with solution x(t)=x0·e^(λt).
- Difference Equations to Differential Equations — Section 6.5: Inverse Trigonometric Functions
Section 6.5 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations' covers the definitions, graphs, derivatives, and integrals of the inverse trigonometric functions — arctan, arcsin, and arcsec. The section addresses partial fraction decomposition with irreducible quadratic factors, completing the square, and trigonometric substitution techniques. A substantial problem set extends coverage to arccos, arccot, arccsc, Taylor series for arctan, and approximation of pi.
- Difference Equations to Differential Equations — Section 6.6: Trigonometric Substitutions
Section 6.6 of Dan Sloughter's open calculus textbook presents trigonometric substitution as a systematic method for evaluating integrals containing radicals of the form sqrt(a^2 - x^2), sqrt(a^2 + x^2), and sqrt(x^2 - a^2). The section covers sine, tangent, and secant substitutions with worked examples, geometric interpretations via right-triangle diagrams, and a set of practice problems including both indefinite and definite integrals.
- Difference Equations to Differential Equations — Section 6.7: Hyperbolic Functions
Section 6.7 of Dan Sloughter's open calculus textbook introduces the six hyperbolic functions (sinh, cosh, tanh, coth, sech, csch), derives their derivatives and integrals from exponential definitions, and develops inverse hyperbolic functions with logarithmic closed forms. The section demonstrates how hyperbolic substitutions simplify integrals such as those involving sqrt(1+x^2) and sqrt(x^2-1), providing an alternative to trigonometric substitution methods. Practice problems covering differentiation, integration, and graphing are included.
- Difference Equations to Differential Equations: Section 3.1 Best Affine Approximations
Section 3.1 of Dan Sloughter's open calculus textbook introduces the concept of best affine approximations to functions, rigorously defining the tangent line as the unique affine function T whose approximation error R(h) is o(h) — that is, goes to zero faster than h itself. The section develops the formal definitions of o(h) and O(h) (little-o and big-O notation), works through several concrete examples including f(x) = sqrt(x) and f(x) = x^2, and culminates in the formal definition of the derivative as the slope of the best affine approximation.
- Difference Equations to Differential Equations: Section 4.2 — Numerical Approximations of Definite Integrals
Section 4.2 of Dan Sloughter's open calculus text presents four numerical methods for approximating definite integrals: the left-hand and right-hand rules (error O(1/n)), the trapezoidal rule and midpoint rule (error O(1/n²)), and Simpson's rule (error O(1/n⁴)). The derivations use the Mean Value Theorem and Taylor-polynomial arguments to bound errors rigorously, and worked examples illustrate convergence rates with tabulated approximations for benchmark integrals.
- Difference Equations to Differential Equations: Section 4.5 More Techniques of Integration
Section 4.5 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations,' covering integration by parts derived from the product rule, along with trigonometric identity techniques for evaluating integrals involving powers of sine and cosine. The section presents the standard udv = uv - vdu formula, works through numerous examples including definite integrals, and concludes with a problem set and discussion of computer algebra systems as modern tools for symbolic integration.
- Difference Equations to Differential Equations: Section 4.7 More on Area
Section 4.7 of Dan Sloughter's open calculus textbook extends the definite integral to computing areas of regions bounded by two curves, treating both x-axis and y-axis formulations. The section derives the area formula via Riemann sum limits and works through several examples involving polynomial, trigonometric, and radical functions. A fourteen-problem exercise set follows, culminating in a Simpson's rule application for estimating lake surface area.
- Difference Equations to Differential Equations: Section 6.3 — Models of Growth and Decay
Section 6.3 of Dan Sloughter's open calculus textbook covers mathematical models of growth and decay using differential equations. Topics include compound interest (continuous compounding limit), uninhibited exponential growth and decay (population growth, carbon-14 dating), and the logistic differential equation for inhibited growth with solved examples fitting US population data. The section includes 14 practice problems.
- Differentiability
A four-page lecture note introducing the concept of differentiability for real-valued functions. The text develops the difference quotient and its limit as the formal definition of the derivative, works through examples for constant, linear, and exponential functions, and explains points of non-differentiability including corners and domain endpoints on closed intervals. The relationship between differentiability and locating maxima and minima — requiring inspection of both critical points and non-differentiable points — is discussed with worked examples.
- Differentiation of Compositions of Functions (Section 3.4)
Section 3.4 of Dan Sloughter's open calculus text 'Difference Equations to Differential Equations,' covering the chain rule for differentiating composite functions with formal proof and worked examples. The section extends power rule differentiation to rational exponents and introduces implicit differentiation, with applications to related rates problems. An 18-problem exercise set reinforces chain rule computation, implicit differentiation, and applied rate-of-change scenarios.
- Differentiation of Polynomials and Rational Functions
Section 3.3 from the open textbook 'Difference Equations to Differential Equations' by Dan Sloughter covers differentiation rules for polynomials and rational functions. The section derives and presents the power rule (d/dx x^n = nx^(n-1)) for positive and negative integer exponents, the constant multiple rule, the sum/difference rule, the quotient rule, and the product rule, with worked examples and practice problems.
- Differentiation of Trigonometric Functions
Section 3.5 of 'Difference Equations to Differential Equations' by Dan Sloughter, deriving the derivatives of all six trigonometric functions from first principles using limit arguments. The section establishes the fundamental limits sin(h)/h → 1 and (cos h − 1)/h → 0 via geometric squeeze-theorem reasoning, then derives the derivative rules for sin, cos, tan, cot, sec, and csc. Worked examples apply the chain rule and product rule to composite trig expressions, with a problem set and a discussion of symbolic versus numerical differentiation.
- Digi-Comp I Instruction Manual (1963)
The original Digi-Comp I manual: operating the machine, coding sheets and every experiment.
- Digi-Comp II Instruction Manual
The original Digi-Comp II manual: counting, adding, multiplying, complementing, subtracting and dividing with marbles.
- Digilent Analog Discovery Pro ADP3450 / ADP3250 — Specifications (rev 0924)
Specification sheet for the mixed-signal bench instrument chosen for the light-gun build: input ranges, buffer depth, single-ended inputs, no current input.
- Digital-Experimentiergerät DEX 100 — Beschreibung
Operator manual for the Telefunken DEX 100 Digital-Experimentiergerät (digital experimenter), a modular digital logic training and experimentation system also usable as a digital supplement to Telefunken desktop analog computers (RAT 700 NE, RA 741, RA 742). Covers the system's plug-in elements (RS/JK flip-flops, amplifiers, inverters, time elements, relay amplifiers, diode logic, clock generator), technical specifications (220 V / ~80 W, 584×550×410 mm, ~30 kg), programming field wiring with patch cords, and interfacing with analog computers. Includes circuit schematics for all module types.
- Digitalzusatz DEX 102 — Beschreibung und Bedienungsanleitung
Description and operating manual for the AEG-Telefunken Digitalzusatz DEX 102, a freely programmable digital logic unit designed as a companion to analogue computers. The 39-page manual covers technical specifications (clocked JK flip-flops, AND/OR interconnection elements, relay amplifiers, adjustable timer elements, and a multi-frequency clock generator), physical construction, programming via a patch-cord field, and connection to the RA 742 desk calculator for hybrid analogue-digital computation. Includes a full circuit diagram appendix and an element reference chart covering the DEX 100/DEX 102 family.
- Digitalzusatz DEX 102 — Informationsblatt
Two-page AEG/Telefunken product information sheet for the DEX 102 digital add-on unit designed to expand desk-type analog computers with digital capability for hybrid computation. Describes use cases (automated experiment control, machine computation with A/D and D/A conversion), special features (modular plug-in expansion, full integration into the analog computer desk chassis), and technical data including 10/12-bit converter options, 19-inch rack construction, 220 V/50 Hz power, and compatible AEG analog computer systems.
- DIN 40700 Blatt 18: Schaltzeichen — Analogrechentechnik
DIN 40700 Sheet 18 (October 1969) is the German national standard defining graphical circuit symbols for analog computing technology. It catalogs 40 standardized symbols for linear computing elements (summing amplifiers, integrators, complementary integrators, track-and-hold units), nonlinear elements (multipliers, dividers, function generators, limiters, comparators), and hybrid (analog-digital) elements. The standard was prepared by the Electronics Standards Committee of the German Standards Institute (DNA) in alignment with IEC recommendations.
- Diodes AP33772S I2C USB PD3.1 EPR Sink Controller — Datasheet (DS46176)
The proposed AVS 24 V sink (UP-5).
- Diodes Inc. AL5809 60 V Two-Terminal Constant-Current LED Driver — Datasheet
Two-pin linear constant-current regulator in fixed current versions; a candidate driver for the IR emitter bars.
- Distance, Position, and the Length of Curves
Section 4.8 from Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations,' covering three applications of definite integrals: computing distance traveled from a velocity function, recovering position from velocity and initial conditions via the Fundamental Theorem of Integral Calculus, and deriving the arc-length integral formula for plane curves. The section includes worked examples involving oscillating springs, numerical integration, and curves such as y = x^(3/2), y = x^2, and y = sin(x), along with a ten-problem exercise set.
- Divide and Multiply with a Wheatstone Bridge
A two-page article from Radio-Electronics (June 1960) by Forrest H. Frantz Sr. describing how a properly configured Wheatstone bridge circuit can function as a simple analog calculator for multiplication and division. The article presents the bridge resistance relationship (A/B = C/D), construction instructions for a practical panel-mounted calculator using potentiometers and a null detector, and several worked example problems demonstrating its use.
- DIY Adaptive Game Controllers (Adafruit Learning Guide)
The Xbox Adaptive Controller 3.5 mm switch convention, used for the pedal jack. PDF export last updated 2025-08-20.
- DIY MAC-10 Construction Guide (Practical Scrap Metal Small Arms Vol. 6)
Sheet-metal construction guide for a MAC-10-pattern submachine gun.
- DO 910 Simulationssystem — Technisches Handbuch
Technisches Handbuch for the Dornier DO 910 hybrid simulation system, covering system overview, disassembly/reassembly, calibration of all analog computing element modules (summing amplifier, integrator, multiplier, variable function generator, dead-time element), IEC/IEEE-488 bus interface, ADC and MDAC calibration, and full schematic diagrams for all plug-in boards. The DO 910 uses a ±10 V machine unit with ±15 V/±12 V/+5 V supply rails and is controlled by a Commodore CBM 4032/8032 computer via an IEC/IEEE-488 bus.
- DO-80 Prototyp — Standardbestückung, Spezifikationen und Schaltungsunterlagen
Internal engineering dossier for the Dornier DO-80 analog computer prototype, containing the standard module configuration (8 integrators/summers, 4 summers, 4 inverters, 4 multipliers, 2 comparators, 8 potentiometers), detailed electrical specifications, hand-drawn circuit schematics for every plug-in module (integrators, summers, comparators, control unit, timer, power supplies, reference voltage), wiring harness diagrams, individual integrator control and potentiometer modules, mains connection board, and a comprehensive set of mechanical construction drawings with dimensioned front-panel and housing cutout layouts. Power supply is 220 V / 50 Hz, approximately 40 W; machine dimensions 443 × 237 × 277 mm; amplifiers are BB 3307/12C and BB 3308/12C op-amps with ±15 V rails and ±10 V reference; compute time adjustable from 0.1 s to 110 s.
- Donner Model 3000 Analog Computer Operating Handbook
Operating handbook for the Donner Model 3000 analog computer, a DC electronic differential analyzer with ten operational amplifiers (pentode-input, cathode-follower output) capable of solving differential equations. Covers specifications (open-loop gain >10,000, bandwidth to ~10,000 cps, output ±100V at 5mA), theory of operation including summing, integration, sign changing and scaling, operating instructions, and servicing. Includes schematic drawings for the power supply and amplifier/switching circuits, plus problem board layout.
- Dornier DO 80 Analogrechner — Bedienungsanleitung
Operator manual for the Dornier DO 80, a compact 10-volt desktop analog computer in a 19-inch rack enclosure. Covers front-panel controls, operating modes (IC/HT/Compute, repetitive and single-shot), rear-panel I/O for parallel multi-computer coupling and external recorders, and construction and patching of integrator, summing amplifier, multiplier, and potentiometer modules with programming examples. Specifications include amplifier bandwidth >20 kHz, integrator drift 80 μV/s in Hold, and multiplier static error 1% FS.
- Dornier-Analogrechner 240/720 Programmierfeld
A single-page color-coded patch panel reference sheet (Programmierfeld) for the Dornier Analogrechner 240/720 analog computer. The diagram illustrates the full jack matrix layout with color-distinguished rows for integrators, summing amplifiers, coefficient potentiometers, comparators, and switches, enabling the operator to record and reproduce program patch configurations. Blank 'Programm' and 'Programmierer' fields at the bottom allow hand-written identification of specific programs.
- Doubly Focused Enumeration of Locally Square Polynomial Values
Software sieving that superseded the special-purpose sieve machines for pseudosquare searches.
- Doug Hart (AA3S) — NanoVNA Introduction: Antenna Analyzer & So Much More
- DSP Y 1001B 9mm機関けん銃 — Ministry of Defense Specification for the 9 mm Machine Pistol (2003, rev. 2008 and 2010)
The Ministry of Defense procurement specification for the 9 mm machine pistol (the Minebea M9), 2003 with the 2008 and 2010 amendments: clauses 2.1–2.9, Table 1 and Figures 1 and 2. The Minebea PM-9 dive's primary source for the gun's official description.
- Dual Operational Amplifier Type AA1054.2 — Instruction Manual
Instruction manual for the Solartron AA1054.2 Dual Operational Amplifier, a plug-in unit housing two independent general-purpose DC operational amplifiers for summing, integrating, or inverting operations. Covers electrical specifications (output ±100 V, DC gain >10^7, input current <10^-10 A, bandwidth ≥5 kc/s at gain of 10), installation and operation with the TX1055.2 six-unit mounting rack, circuit description, test procedures, and a component list. Issue One, dated May 1964; Mod. Ref. 1054.2/15 and 1053.2/15.
- DX Engineering BTV Multiband HF Vertical Antennas — Assembly & Installation Instructions
- Dynalloy Flexinol Actuator Wire — Technical Data
Contraction force, current and cooling (relaxation) times by wire diameter.
- Dynamische Simulatoren in der Reaktorentwicklung. Ein Vergleich
A 1969 external technical report (No. 8/69-1) from the Kernforschungszentrum Karlsruhe comparing analog, digital, and hybrid dynamic simulators for nuclear reactor development applications. The authors evaluate simulator types against criteria of computational accuracy, speed, cost, and ease of use, with emphasis on stiff differential equation systems arising in reactor kinetics and thermal-hydraulics. Benchmark test cases compare specific systems including EAI HYDAC, Telefunken RA 800, IBM 360 with CSMP, and a large hybrid system (~500 op-amps), concluding that hybrid computers offer the best performance for demanding reactor-dynamics problems while digital simulation is preferred for precision work.
- E-18898-A-1 Test Distributor Selector Circuit
Early AE circuit explanation for a test distributor selector.
- E-580059-A: Selector Circuit Explanation (issue 12, with Addendum 1, 1974)
Circuit explanation for selector H-580059; the addendum covers drawing issues 13–22.
- E-580260 Connector Circuit Explanation (local or toll, trunk/level hunting, night line)
Step-by-step circuit explanation of an AE connector; the textual companion to H-580260.
- E-75159 10-Line Isolated PAX, 24 Volts, circuit explanation
Circuit explanation of a small 10-line AE PAX at 24 V: the closest published analogue to a 3-phone home PBX.
- E-85175 Dial Speed Spotter (pulse testing) circuit explanation
Circuit explanation for AE dial speed/pulse testing circuit; useful for checking dial speed and break ratio.
- E-85289 / AH-85289 Linefinder Test Circuit for Switch Test Stand
Circuit explanation and adjustment for AE's bench test stand that exercises a linefinder out of the shelf; model for bench-testing switches.
- E.S.R. brochure: The Amazing Dr. NIM, Think-a-Dot, Digi-Comp I
E.S.R. sales brochure for its three logic toys.
- EAI — Report Nr. 017, April–Mai 1970
Issue 17 (April–May 1970) of EAI Electronic Associates GmbH's German-language customer newsletter, covering new EAI-640 digital computer configurations (640/100, 640/200, 640/300) and peripherals, hybrid expansions for the TR-48 analog computer, installation reports for the EAI-680 at Technische Hochschule Wien and EAI-590 at DFVLR Braunschweig, and the EAI-690 hybrid system. Includes a technical article on amplitude and phase measurement using the analog computer (by Dipl.-Ing. F. Vogt), plus product announcements for the EAI 430/200 Data Plotter, Brush Mark 220/260 strip-chart recorders, DCFG (Digitally Controlled Function Generator), and the DART data acquisition and recording terminal.
- EAI 1000 Reference and Maintenance Manual
The Reference and Maintenance Manual for the EAI-1000 Micro Processor Controlled Analog/Hybrid Computer System covers the architecture, operating procedures, and maintenance of this education-oriented hybrid computing system. The EAI-1000 is built around a modular bus system supporting up to three CD analog modules, a display module, a microprocessor control card, and optional digital expansion; analog computing elements include integrators, summers, multipliers, comparators, potentiometers, and free-function generators. The manual details all computing components and their patch-panel connections, digital logic elements (gates, flip-flops, counters), control modes (IC/OP/REP), overload protection, circuit schematics, and parts listings for maintenance purposes.
- EAI 180 Computer Operator's Reference and Maintenance Manual
The Operator's Reference and Maintenance Manual for the EAI 180 Analog-Hybrid Computer covers initial set-up, operating procedures (readout and meter control, display and mode control, digital control), and detailed descriptions of all computing components including linear (summers, integrators), non-linear (function generators, comparators, multipliers), and digital logic elements. The manual also includes maintenance procedures for the main frame and each panel type, three appendices on unit scaling, transfer-function simulation, and representation of constraints and nonlinearities, plus a full set of circuit diagrams for all major sub-assemblies. The EAI 180 is a compact, solid-state general-purpose analog-hybrid computer designed for office or classroom use, rated for 240V/50Hz or 110V/60Hz operation.
- EAI 2000 Analog Reference Handbook
Comprehensive reference handbook for the EAI 2000 analog/hybrid computer system, covering system overview, the program panel layout, all analog computing components (coefficient units, summers, integrators, multipliers, function generators, limiters), logic computing components, system and interface components, and the MACS (Master Analog Computer System) display and keyboard command set. The handbook serves as the primary operator reference for programming, patching, and operating the EAI 2000 in stand-alone analog, hybrid non-time-critical, and hybrid time-critical configurations. Published April 1980 as Pub. No. 00 800.2107-0 RC0.
- EAI 380 Analog/Hybrid Computing System
Marketing brochure and specification sheet (Bulletin No. 853094-2 / 853089-1, dated April 15, 1969) for the EAI 380 10-volt desk-top analog/hybrid computer. The document describes the system as EAI's lowest-cost hybrid-capable machine, expandable from 10 to 54 amplifiers in a single mainframe, with features including electronic mode control, quarter-square multipliers, variable diode function generators, high-speed comparators, a self-contained digital voltmeter, and an integrated-circuit plug-in logic system. Full component specifications are provided covering operational amplifiers, integrators, summers, inverters, multipliers, track/store networks, comparators, function relays, sine/cosine generators, and digital logic cards.
- EAI 580 Analog/Hybrid Computing System — Maintenance Series: Computing Components
This maintenance manual covers the computing components of the EAI 580 Analog/Hybrid Computing System, including dual and quad DC amplifiers, integrators, summing integrators, quarter-square multipliers, diode function generators, potentiometer-comparator-function relay trays, track/store units, DG switches, and logic interface circuits. Each section provides technical data, theory of operation, circuit description, maintenance and adjustment procedures, replaceable parts lists, and schematics. Published by Electronic Associates, Inc. in May 1966 (Publication No. 00 800, 5020-A).
- EAI 580 Analog/Hybrid Computing System Maintenance Series: Console Components
This is the Console Components volume of the EAI 580 Analog/Hybrid Computing System Maintenance Series (Publication No. 00 800.2056-0, May 1968), covering eight chapters: system introduction with installation data, general maintenance procedures, computer mode and time-scale control, readout selector system, servo and handset attenuators (up to 70 motor-driven units), overload indicators, the 0.10.0354 power supply (plus/minus 10 V reference, plus/minus 15 V, +30 V regulated outputs), and AC/DC power distribution including the motorized patch-panel drive. Each chapter includes theory of operation, troubleshooting guidance, replaceable-parts lists, and wiring diagrams; Appendix 2 reproduces the 21-sheet console wiring drawing D00 093 0062 OW.
- EAI 580 Computing System — General Maintenance Instructions (Chapter 2)
Chapter 2 of the EAI 580 Computing System maintenance documentation, covering general maintenance instructions. The chapter details preventive maintenance schedules (daily/weekly and semi-annual checks covering power supplies, amplifiers, multipliers, function generators, DVM calibration, and potentiometer accuracy), printed-circuit board soldering and component replacement techniques, transistor and diode servicing procedures including heat-sink mounting with silicone grease, and general system troubleshooting guidance using dynamic testing, oscilloscope display, and plug-in tray substitution. Maintenance equipment recommendations specific to the EAI 580 are also provided.
- EAI 580 Console Chapter 7: The 0,10,0354 Power Supply
Chapter 7 of the EAI 580 Analog Computer console manual, covering the Model 0,10,0354 Power Supply in detail. The chapter describes electrical specifications (±30 V, ±15 V, ±10 V, ±5 V regulated outputs plus ±10.000 V reference), circuit operation of the series regulators and chopper-stabilized reference amplifiers, step-by-step adjustment procedures, and foldout schematics. Appendix 1 provides a complete replaceable-parts list with EAI part numbers for all printed-circuit cards in the power supply.
- EAI 580 Console Handbook — Chapter 4: Readout Selector System
Chapter 4 of the EAI 580 analog computer console handbook covering the Readout Selector System in full detail. The chapter describes the address select circuit (models 0.51.0359, 0.51.0360, 0.11.0213), all address-mode pushbutton switch circuits (DIG I/O, PP, F, D, D/10, P, A), the voltmeter (VM) null circuit and FUNCTION/RANGE switch functions, and the relay-matrix potentiometer readout scheme. Two appendices provide replaceable-parts lists with EAI part numbers dated October 1967 for seven card assemblies (Select Mother Card, Select Amplifier Network Card, Select Stabilizer Card, Monitor Panel, Voltmeter Card, Address Select Card, Units and Tens Select Card), plus an indexed set of schematics and wiring diagrams for the keyboard panel, select mother card, monitor panel, address select, units/tens select, and the 0.13.0046 Voltmeter Card.
- EAI 580 Console Manual — Chapter 6: Overload Indicators
Chapter 6 of the EAI 580 analog computer console manual, covering the visual overload indicator subsystem. The chapter explains the theory of operation for amplifier overload detection circuits (including NRPD and audio overload circuits), provides maintenance and troubleshooting procedures for the overload panel, and includes a replaceable parts list with tables for the control tray, control cards 1 and 2, and visual overload alarm assemblies (models 0.20.1018-2 and 0.20.1018-3). An appendix of engineering drawings provides schematics for the control tray wiring, control card circuits, the visual overload alarm assemblies, and the indicator panel layout.
- EAI 580 Console Manual — Chapter 8: Power Distribution
Chapter 8 of the EAI 580 Console maintenance manual, covering the AC primary power distribution system (115 V / 230 V selectable via terminal board TB1 jumpers), the motor-driven patch panel engage/disengage drive system, and DC secondary power distribution via bus bars from the 0.10.0354 Power Supply. The chapter is followed by Appendix I (replaceable parts lists dated 10/11/67 for Motor Mounting, Dynamic Brake, OFF-ON DIS-ENG Card, Bus Bar Network Card, and Wired Cabinet) and Appendix 2 (drawings index and schematics for the Dynamic Brake and the OFF-ON/Dis-Eng Card, EAI drawing nos. 000 012 1092 IW and C10 012 1093 OW).
- EAI 580 Desk-Top Analog/Hybrid Computing System
Product brochure for the EAI 580 Desk-Top Analog/Hybrid Computing System, a fully solid-state 10-volt desk-top machine capable of up to 80 computing amplifiers and 8 comparator amplifiers. The brochure describes the system's master control panel, analog programming system, digital logic section (synchronous clocked logic with 32 gates, general-purpose registers, counter/timers), servo-set potentiometer system, system expansion options, and peripheral equipment. Application areas covered include analog/hybrid computation, iterative computation, full hybrid computation, bio-medical engineering, chemical process industry, aerospace, and education.
- EAI 580/680 Scientific Computing System Maintenance Series: Digital Voltmeter — Chapters 4–5 (Maintenance and Calibration)
Chapters 4 and 5 of the EAI 580/680 Maintenance Series manual for the Model 28.268 Digital Voltmeter (DVM). Chapter 4 covers maintenance procedures including test connector pinout, reference circuit and power supply checks, input amplifier balance verification, resistor matrix and comparator checkout, digitizing circuit troubleshooting, accuracy checks with tabulated input/readout tolerances, and display unit lamp replacement and lens adjustment. Chapter 5 provides the full calibration procedure, specifying required test equipment (precision voltage divider, galvanometer, stable DC source), reference level adjustment using the 6.750 Reference Amplifier, full-scale adjustment, and summing resistor trim pot procedures for the ±100 V, ±10 V, ±1 V, and ±0.1 V ranges.
- EAI 680 Analog Computer: Hybrid Computation Laboratory Users Manual
A concise 14-page users manual produced by the Carnegie-Mellon University Hybrid Computation Laboratory for the EAI 680 analog computer, dated September 1968. Covers the full workflow from problem preparation (problem statement, block diagram, scaling, computer diagram, static check) through patching and analog computer operation, with cautions and hints for safe use. Includes blank assignment sheets for potentiometers, amplifiers, logic components, and nonlinear components used in the CMU lab.
- EAI 680 Maintenance Pocket Guide
A compact pocket guide prepared by the EAI Technical Training Department to assist technicians maintaining the EAI 680 analog/hybrid computer, published October 1969. The guide covers operating equipment (patch cords, pins, connectors), a full inventory of major computing trays (analog, control, and logic types with old- and new-series part numbers), patch panel overlays, special tools and accessories, expendable supplies for peripheral units (8850 plotter, 8875 recorder, 8880 display, 8881 monitor oscilloscope), connector repair kits, fuses, lamps, and a semiconductor replacement guide listing direct replacements, substitutes, and special-category diodes and transistors. Console adjustment diagrams, bus layouts, plug-in component and integrated-circuit pin layouts, and chassis connector layouts are included as fold-out illustrations.
- EAI 680: A Hybrid Computer to Grow With
A 12-page product brochure (Bulletin No. AC65064, September 1965) from Electronic Associates, Inc. describing the EAI 680 Scientific Computing System, a hybrid analog-digital computer. The brochure covers applications across process industries, universities, life sciences, and aerospace, and highlights hybrid capabilities including electronically addressed servo-set potentiometers, parallel digital logic, 500 kc bandwidth operational amplifiers, and track/store units with sub-microsecond reset. The console houses up to 156 amplifiers, 120 potentiometers, quarter-square multipliers, and variable diode function generators in a compact 5 x 5 x 2.5 foot welded steel frame operating on 10-volt solid-state circuitry.
- EAI Analog/Hybrid-Rechner Newsletter Nr. 013, Oktober 1967 – Februar 1968
Quarterly German-language customer newsletter from EAI Electronic Associates GmbH (Aachen), covering October 1967 to February 1968. The featured technical article details the analog computer simulation of the pumping action of the left cardiac ventricle on the EAI 580, including patch diagrams and oscillograms for normal and pathological heart behaviour (valvular insufficiency, stenosis). Additional content describes new plug-in modules for the EAI 580, the Series 10 special-purpose analog data processor, Brush Mark 26C 6-channel recorder, Variplotter 1140 M XY plotter, EAI's role in the Apollo re-entry simulation on the EAI 690, a TR-20 fruit-tree dynamics simulation at Rutgers University, and scheduled analog/hybrid training courses for early 1968.
- EAI Announces STARLIGHT System
A single-page EAI internal company newsletter article announcing the STARLIGHT simulation system, EAI's newest and fastest analog/hybrid simulation computer. The article describes STARLIGHT as approximately seven times faster than the runner-up CRAY machine, occupying about 55 square feet of floor space, fitting in a two-drawer file cabinet form factor, and priced at approximately $150,000. The piece also notes an ongoing NASA study contract to prove the concept by building a hardware prototype and running benchmark applications.
- EAI Computer Users' Group Newsletter, Fourteenth Edition
The fourteenth edition (February 1986) of the EAI Computer Users' Group International Chapter newsletter covers the 1985 users' group meeting held in Genova/Santa Margherita, Italy, with 27 attendees from eight countries. Technical content includes EAI product status reports on the SIMSTAR non-homogeneous multiprocessor (including the Gould CONCEPT 32 digital arithmetic processor family integration, STARTRAP programming system, and ACSL-compatible real-time DAP simulation language), plus user-presented papers on analog and hybrid simulation of satellite attitude controllers, servomechanisms, gas utility systems, motor-vehicle drives, DFVLR research aircraft, and interface experiences with the EAI 2000. News from the North American Chapter and articles of organization are also included.
- EAI MiniAC Reference Handbook
The EAI MiniAC Reference Handbook is a 224-page operator reference for the Electronic Associates, Inc. MiniAC hybrid analog computer. The handbook covers the machine's computing components — including integrators, summers, track-store units, multipliers/dividers, function generators, potentiometers, comparators, and a digital logic section with AND-gates, J-K flip-flops, counter/timer, and monoflop — along with patchboard programming procedures and operating modes (IC, OP, HD, PP, SP, SL). It serves as the primary programming and operation reference for laboratory or classroom use of the MiniAC.
- EAI Mitteilungsblatt für Kunden und Freunde der EAI Electronic Associates GmbH — Nr. 009, September/Oktober 1966
Customer and dealer circular issued by EAI Electronic Associates GmbH (Aachen) for September–October 1966, announcing participation at the Electronica 66 trade fair in Munich. The newsletter introduces the EAI 680 analog/hybrid computer (fourth-generation hybrid, 10 V reference, up to 156 amplifiers, 4080-hole patchboard, fully transistorized, 150×150×75 cm, no air conditioning required), describes the new all-solid-state VARIPLOTTER 1133 M coordinate recorder (28×43 cm, ±0.2% accuracy, 50 cm/sec slew rate, DM 6,255), and lists new logarithmic and AC input modules for the VARIPLOTTER 1110, along with prices, Class B used-equipment availability, and an EAI event calendar.
- EAI Mitteilungsblatt Nr. 002 — August 1965
An eight-page German-language customer newsletter (Mitteilungsblatt) from EAI Electronic Associates GmbH Aachen, dated August 1965, covering general announcements (office expansion, trade show appearances, analog computing course), technical announcements for the EAI-8875 multi-channel rectilinear recorder (12 paper speeds, forced-fluid ink system, up to 8 channels), the Electronic Mode Control (EMC) upgrade option for the TR-48/58, and the new Type 1026.003 transistorised digital multimeter. Also introduces the PDS 1020 general-purpose digital computer (magnetostrictive delay-line memory, 2,048 words, variable word length 4–24 digits, under DM 100,000) and provides updated DM price lists for TR-20 and TR-48 accessories and the 8875 recorder series.
- EAI Mitteilungsblatt Nr. 004 — November 1965
Monthly newsletter (No. 004, November 1965) from EAI Electronic Associates GmbH (Aachen), announcing EAI's new distribution of Brush Instruments recording systems in West Germany, providing specifications for the VARIPLOTTER Type 1110 XY recorder (28x43 cm format, 0.075% static accuracy), listing stock-available TR-20 and TR-48 Class B analog computers, and advertising new features of the TR-48 including hybrid operation with the DES-30 digital expansion system and expansion to 58 computing amplifiers. Also includes a product listing for Josef Heinzinger high-voltage power supplies and MC laboratory cable accessories.
- EAI Mitteilungsblatt Nr. 7 — Mai/Juni 1966
The seventh issue of EAI's German-language customer newsletter (May–June 1966) covers three main topics: a technical description of the PDS 1020 general-purpose digital computer including its magnetostrictive delay-line memory, seven-register architecture, and INTERPRETER software; a detailed technical article on iterative computing methods for analog computers using track-store (sample-and-hold) units for analog point storage; and company news including the use of the EAI PC 12 process computer in the Surveyor Moon-landing mission, Class-B used equipment availability, and EAI delivery milestones for TR-series machines.
- EAI Products and Services
A 12-page product and services brochure from Electronic Associates, Inc. (EAI) covering the company's full line of analog, digital, and hybrid computing systems, including the EAI 8400 digital computer, EAI 8800 and EAI 680 analog computers, EAI 8900 and EAI 690 hybrid systems, desk-top units (TR-20, TR-48, EAI 580), and the EAI 380 modular analog/hybrid system. Additional products described include variplotters (Series 205, 95-361, 1110-1140), EAI dataplotters, reed-relay scanners (Series 6800), digital measuring systems (Series 6200), digital voltmeters (Series 6000), and application systems such as the EAI PACE II chromatographic laboratory system and an EAI cement control computer. The brochure was held by the Rechenzentrum Universitat Kiel.
- EAI Report Nr. 012 — EAI 580 Analog/Hybrid-Rechner
Customer newsletter (Report No. 012, May–September 1967) from EAI Electronic Associates GmbH, Aachen, announcing the EAI 580 Analog/Hybrid Computer: a desktop system with 80 computing amplifiers, 70 servo potentiometers, ±10 V reference, ±0.01% linear accuracy, built-in parallel logic, and interface for coupling to digital computers (EAI 640, PDP-8-S), priced between DM 50,000 and DM 250,000. The report also includes a historical timeline of EAI analog and hybrid systems from 1948 to 1967, information on the Brush MARK 220 two-channel recorder, new EAI digital voltmeter models (6240 rack-mount and 6250 TR-10/TR-20 accessory), and details of the December 1967 EAI Analog/Hybrid Computing Course with full curriculum.
- EAI Report Nr. 016 — Mitteilungsblatt der Electronic Associates GmbH
EAI Report Nr. 016 is a German-language company newsletter (May–June 1969) from Electronic Associates GmbH, Aachen. It covers Clevite/Brush strip chart recorders (including the Mark 280 6-channel portable and the Datapoint multipoint recorder), introduces the EAI 430 Dataplotter (an XY plotter with RAPID polynomial interpolation), presents a technical article on autocorrelation analysis of stochastic time functions using hybrid computers (including the EAI-380), and includes a programming exercise on the pursuit problem, a Hannover-Messe 1969 trade-fair report, an Apollo 9 tribute, the EAI 380 system description, a trade-in program announcement, and MC laboratory connector accessories.
- EAI TR-48 Analog Computer -8V / 2V Power Supply Schematic
A single-page vector schematic depicting the -8V and 2V power supply circuit of the EAI TR-48 analog computer, drawn by Josh Bensadon on October 10, 2012. The diagram shows a transformer (T1) with 24-ohm secondary windings, rectifier diodes (D1, D2), filter capacitors (C1, C2), fuses (F1 3A, F2 0.5A), a 2N1218 transistor regulator, a zener diode reference (-1.8V, 100mW), and a 22-pin Amphenol connector providing -8V, -8V return, 2V, 2V return, and 2V control outputs; AC input provisions for both 120VAC and 240VAC are shown. A top-view component placement inset is included.
- EAI TR-48 Analog Computer Module Configuration on York University Computer, As Built for Installed Board
A single large-format schematic drawn to scale by Josh Bensadon (September 5, 2012, revised October 10, 2012) documenting the module configuration and patch panel layout of an EAI TR-48 analog computer as installed at York University. The drawing identifies each installed module bay (amplifiers, attenuators, multipliers, and patch connections) with shunt types keyed by EAI part numbers (005-172 through 005-174) and resistor values ranging from 100K to 10M ohm at 1% tolerance. Revision notes record corrections to wiring for a board that came pre-installed and minor fixes to module naming and labels.
- EAI-1000 Diagnostic Routines (Section 8.11–8.13 and Diagnostic Box Reference)
This document is an extracted section (pages 8.25 onward) from the EAI-1000 reference manual covering the use of the diagnostic box and diagnostic software routines for troubleshooting the EAI-1000 hybrid analog computer. It describes the diagnostic box hardware — a 40-way flat-cable peripheral that replaces the HCI microprocessor card to isolate faults — and provides a numbered test matrix covering data bus/RAM storage, keyboard reading, device selection for the analog bus, A/D conversion, and the display panel. Each test entry specifies the switch settings ([AB], [CD], [EF]), the pass/fail criteria observable via oscilloscope or the indicator register, and details on chip-level failure modes (IC42, IC38, IC35, RAM chips 8111/8085/8212, EPROMs, and TTL buffers).
- EAI-Mitteilungsblatt Nr. 015 — EAI Electronic Associates GmbH
The EAI Mitteilungsblatt (newsletter) Nr. 015, covering August 1968 through April 1969, is a multi-article German-language customer bulletin from EAI Electronic Associates GmbH in Aachen. It introduces the new EAI-7800 analog/hybrid computer (294 amplifiers, 100 V reference, 42 integrators, 36 multipliers, configurable for hybrid operation with the EAI-640 digital computer), describes the EAI-590 hybrid system (comprising the EAI-580 analog computer, EAI-640 digital computer, and EAI-693 interface), and reports on the EAI-8900 installation at the UK Central Electricity Generating Board. Additional articles cover EAI's role in NASA Apollo simulations, the PACE II analytical data-processing system for gas chromatography, a driving simulator at TU Berlin using TR-20 analog computers, the 1969 European training course calendar, and a new digital drafting template.
- EAI-Report Nr. 001 — Mitteilungsblatt der EAI Electronic Associates GmbH
The inaugural issue (July 1965) of the EAI-Report, a German-language product newsletter from EAI Electronic Associates GmbH Aachen. It announces EAI's new exclusive distributorship for Germany, describes a modification enabling individual operating-mode control (Reset/Hold/Operate/Time-Scale) on TR-10 integrating networks, and details numerous improvements to the TR-48/58 desktop analog computer including a 58-amplifier configuration, improved multipliers, variable-breakpoint function generators, delay-line and reactor-kinetics networks, fast comparators, and the new DES-30 digital extension system.
- EAI-Report Nr. 010 — Mitteilungsblatt der EAI Electronic Associates GmbH Aachen (Januar/Februar 1967)
Issue No. 010 of the EAI GmbH Aachen internal newsletter (January/February 1967) covers the company's German sales-territory reorganization for 1967 and announces scheduled analog and analog/hybrid computing training courses using the TR-48 and TR-48/DES-30. Technical content includes a detailed description of a sample-and-hold circuit technique for recording rapidly repetitive analog-computer runs point-by-point on a coordinate plotter, plus product notes on the new EAI 640 digital computer, the Brush Recorder Mark 250 strip-chart recorder, Poltron stabilized power supplies, and the EAI Variplotter X-Y recorder series.
- EAI-Report Nr. 011, März–April 1967
The March-April 1967 issue of the EAI-Report (No. 011), published by EAI Electronic Associates GmbH in Aachen, introduces the Series 6200 modular digital measuring system with detailed specifications for its DC integrating voltmeter (Series 6201), digital counter (Series 6202), and AC converter (Series 6203) plug-in modules. A technical article by Dipl.-Ing. K.H. Hortenbach describes an analog computer sample-and-hold circuit that exploits the parallel subroutine technique for efficient polar-to-Cartesian, Cartesian-to-polar, and coordinate-axis-rotation transformations, demonstrating substantial savings in nonlinear computing elements. The issue also covers the Brush logarithmic preamplifier for multi-channel recorders, Class B used-equipment availability (TR-48/58, TR-20), characteristics of the EAI 9000 hybrid scientific computing system, and a calendar of 1967 EAI events across Germany.
- EAI-Report Nr. 014, 4. Jahrgang, März/August 1968
Customer newsletter (4th year, issue 14) from EAI Electronic Associates GmbH Aachen, covering product introductions and new developments across the EAI analog and hybrid computer line for March–August 1968. Highlights include the debut of the EAL-380 analog/hybrid desktop computer (10 V, 36 amplifiers, 400 kHz bandwidth, parallel logic), major EAI-680 enhancements (overload-limiting amplifiers, three-mode EMC integrators, 3-amplifier multiplier plug-ins, expansion system with resolver and coupling subsystems, teletype I/O station, and digitally controlled function generators), the EAI 8900 large hybrid system delivered to the UK's Central Electricity Generating Board, the Series 430 DataPlotter, EAI-640 digital computer installation at TU Berlin, and the European education and training programme.
- Early Work on Dial Telephone Systems
History of early dial systems including Strowger.
- EASE Computer Installation Instructions
Installation instructions for the Beckman EASE analog computer system, covering site preparation, cabinet arrangement, ground bus connections, and 115 V AC line power wiring for the Model 1187 control unit cabinet and Model 1185 operational component cabinets. The manual details d-c voltage requirements and current capacities for the Model 1001, 1010, and 1015 power supplies and provides inter-cabinet cabling procedures for the Model 1041 Operational Amplifier Unit, Model 1031 Multiplier Panel, Model 1051 Multiplier, and associated function generators and set-up units.
- Eaton HV Supercapacitors, Cylindrical Cells — Technical Data 4376
Cell ESR, pulse capability, capacitance tolerance and short-circuit behaviour for high-power EDLC cells.
- Eaton PHB Supercapacitors, Cylindrical Pack — Technical Data 4402
5 V two-cell supercapacitor packs.
- Eclipse Prediction on the Ancient Greek Astronomical Calculating Machine Known as the Antikythera Mechanism
PLOS ONE 9(7): e103275 (CC BY). Reconstructs the Saros dial's eclipse glyphs and argues for an early epoch.
- ECMA-10 Standard
ECMA-10, *Standard for Data Interchange on Punched Tape*, 1st edition, Nov 1965 (25.40 mm tape, 1.83 mm code holes, 1.17 mm feed holes, 2.54 mm pitch, feed track between tracks 3 and 4)
- Edison Fong (WB6IQN) — The DBJ-1: A VHF/UHF Dual-Band J-Pole
- Edmunds, "Some Thoughts on the Confederate LeMat Revolver" — ASAC Bulletin 100 (2009)
A collector of some fifty years who examined more than a hundred LeMats on the models, makers and Confederate deliveries. American Society of Arms Collectors Bulletin 100, pp. 24–28.
- Educational Pamphlet Telephones 3/1 (draft series): Outline of Automatic Step-by-Step System — Post Office Engineering Dept
21 pp. Same series as Library's 3/2
- Educational Pamphlet Telephones 3/1 (final series): Automatic Telephony, Non-Director Multi-Exchange Areas, Trunking Principles — Post Office Engineering Dept
8 pp, image only
- Educational Pamphlet Telephones 3/4 (draft series): Ordinary Final Selectors — Post Office Engineering Dept
34 pp
- Ein elektronischer Koordinatenwandler ohne Diodennetzwerke und seine Anwendung bei der Messwertverarbeitung mechanischer Groessen
A 1977 doctoral dissertation submitted to the Technische Universitat Wien by Dipl.Ing. Fritz Vogel. The work describes a novel electronic coordinate converter that converts Cartesian coordinates to polar coordinates without diode networks, using an arctangent approximation based on the hyperbolic tangent function. The dissertation covers analog and digital implementation methods, circuit design, four-quadrant operation, computational accuracy analysis, and application examples including acceleration measurement and biaxial stress analysis.
- Einstellgerät für polarisierte Relais ON 280 34
Operator manual for the MEDA ON 280 34 adjustment instrument used to set and verify polarized relays (type A 4g/03/XX/V) in the MEDA-T differential analyzer series. Covers technical description, specifications (220 V, 225×250×150 mm, 3.26 kg), step-by-step relay adjustment procedure measuring contact symmetry and overdrive time (Überfallzeit), and a parts list. Oscilloscope connection is supported for visual waveform verification of relay contact dynamics.
- Electronic Analog Computer Primer
An introductory textbook on electronic analog computers by James E. Stice (University of Arkansas) and Bernet S. Swanson (Illinois Institute of Technology), published by Blaisdell Publishing Company in 1965. The book serves as a primer covering the principles, components, and operation of electronic analog computers, intended for students and engineers new to the field. It is part of the Blaisdell Pure and Applied Sciences series, with Leon Lapidus of Princeton University as consulting editor.
- Electronic Counting Circuits
- Electronics and Your Slide Rule, Part I — Step-by-step to Skillful Operation (CIE Electronics Slide Rule No. 515 / Pickett N-515-T)
CIE Auto-Programmed lesson for the Pickett-made CIE electronics slide rule (N-515-T). Fourth Edition, Fifth Revised Printing, October 1966 (copyright 1958, 1962, 1965, 1966). Topics 1-14: holding the rule, the scales, reading graduations, decimal point, multiplication and division. Title page states 'Electronics Slide Rule No. 515, designed by Cleveland Institute of Electronics, U.S. Patent Number 3,120,342'. 34 pp.
- Electronics and Your Slide Rule, Part II — Combined Operations with Electronic Applications (CIE Electronics Slide Rule No. 515 / Pickett N-515-T)
CIE Auto-Programmed lesson for the Pickett-made CIE electronics slide rule (N-515-T). Fourth Edition, Fifth Revised Printing, October 1966 (copyright 1958, 1962, 1965, 1966). Topics 15-24 (lesson 3123-1): CI scale and reciprocals, combined multiplication/division, resetting the slide, repeated operations, A and B scales, squares and square roots, proportion. 43 pp.
- Electronics and Your Slide Rule, Part III — Combined Operations with Electronic Applications (CIE Electronics Slide Rule No. 515 / Pickett N-515-T)
CIE Auto-Programmed lesson for the Pickett-made CIE electronics slide rule (N-515-T). Fourth Edition, Fifth Revised Printing, October 1966 (copyright 1958, 1962, 1965, 1966). Topics 25-36 (lesson 3124-1): the Reactance and Resonance Decimal Point Locator, resonance and reactance problems, the 2pi scale, the H scale, S and T trigonometric scales. Worked Examples 31-43. The key manual for the rule's special scales. 43 pp.
- Electronics and Your Slide Rule, Part IV — Combined Operations with Electronic Applications (CIE Electronics Slide Rule No. 515 / Pickett N-515-T)
CIE Auto-Programmed lesson for the Pickett-made CIE electronics slide rule (N-515-T). Fourth Edition, Fifth Revised Printing, October 1966 (copyright 1958, 1962, 1965, 1966). Topics 37-44 (lesson 3125-1): solving right triangles, circuit problems by triangle rules, the L and Ln scales; summary and appendix. 52 pp.
- Electronics Fun & Fundamentals: Analog Reborn
A Make: magazine article by Charles Platt introducing analog computing concepts through a simple DIY project called EASY (Elementary Analog SYstem), derived from the 1961 General Electric EF-140 kit. The project uses three potentiometers and a multimeter to perform basic analog multiplication, division, and square root operations. The article also discusses the resurgence of analog computing, referencing Anabrid GmbH's educational product THAT (The Analog Thing) and the historical context of analog computers in aircraft simulation.
- Electronics Today International, July 1975
The British magazine Electronics Today International for July 1975, with coverage of Sinclair's calculators.
- Electronics, 29 May 1967: Ise's Low-Voltage Numerical Display Tube
The first public report of Ise Electronics' vacuum-fluorescent numerical tube, from Electronics magazine of 29 May 1967, pp. 212-213.
- Elektronika 155 Passport and Operating Instructions (Russian)
The passport and operating instructions of the Elektronika 155 desk calculator, for economic, statistical, scientific and design calculations (in Russian).
- Elektronika B3-02 Passport (Russian)
The fourteen-page passport of the Elektronika B3-02 desk calculator, an electronic keyboard computing machine (ЭКВМ) with a fluorescent display (in Russian).
- Elektronika B3-14 Circuit Diagram
The circuit diagram of the B3-14 fluorescent-display pocket calculator (in Russian).
- Elektronika B3-18A Circuit Diagram
The two-sheet circuit diagram of the B3-18A scientific pocket calculator, with the K145IP7 chip (in Russian).
- Elektronika B3-18A Operating Manual (Russian)
The operating manual of the B3-18A, the improved version of the first Soviet pocket scientific calculator (in Russian).
- Elektronika B3-21 Operating Manual (Russian)
The 79-page Russian operating manual of the B3-21, the first Soviet pocket programmable calculator (in Russian).
- Elektronika B3-21 Passport (Russian)
The seven-page passport of the B3-21 (in Russian).
- Elektronika B3-26 Circuit Diagram
The circuit diagram of the B3-26 four-function calculator on the K145IP11 chip (in Russian).
- Elektronika B3-26 Passport (Russian)
The four-page passport of the B3-26 four-function pocket calculator (in Russian), digitised by a collector from his own copy.
- Elektronika B3-34 Factory Circuit Diagram (two sheets)
The two-sheet factory schematic of the B3-34: K145IK1302/1303, K145IR2 and K165GF3 chips, the converter and BP2-3 mains unit, the IVL2-8/12 tube with its parameter table, oscillograms, and the note on fitting VD4 forward for a weak display (in Russian).
- Elektronika B3-34 Operating Manual (Russian)
The 165-page Russian instruction booklet of the B3-34 programmable calculator (in Russian).
- Elektronika B3-35 Operating Manual (Russian)
The 67-page operating manual of the B3-35 scientific pocket calculator (in Russian).
- Elektronika MK-51 Operating Manual (Russian)
The Russian operating manual of the MK-51 scientific: keys and modes, technical data (K757IP1-2 chip, IZhTs2-9/7 LCD, 0.001 W, 64 roubles), worked examples, the circuit diagram and voltage diagrams, and the warranty cards (in Russian). Page images scanned by Surok (ru-hpc.narod.ru), 2009.
- Elektronika MK-52 Operating Manual, Book 1 (Russian)
The first of the two Russian books shipped with the MK-52: operation, the EEPROM, the BRP memory modules and worked examples (in Russian).
- Elektronika MK-52 Operating Manual, Book 2 (Russian)
The second Russian book of the MK-52, mostly programs (in Russian).
- Elektronika MK-52 Schematic
The circuit diagram of the MK-52 programmable calculator (in Russian).
- Elektronika MK-52 Schematic, MEU-4 Sheet
A second MK-52 schematic sheet, marked MEU-4 (in Russian).
- Elektronika MK-52 User Manual (English)
A 63-page English user manual for the MK-52 programmable calculator.
- Elektronika MK-61 Calculator Operating Instructions (English translation by José Mesquita)
A 52-page English translation of the MK-61 operating manual (draft 1.0, October 2014), with the translator's notes on the stack, the power supply and DC-DC converter pins, the D2-10M adapter, test procedures, command codes and example programs.
- Elektronika MK-61 Circuit Diagram (Appendix 5 of the manual)
The factory circuit diagram of the MK-61: converter with winding table and transistor operating points, the six K745 chips and their pin tables, the ILC2-12/8L tube and pull-downs, the keyboard matrix, and oscillograms (in Russian).
- Elektronika MK-61 Operating Manual (Russian)
The 90-page Russian operating manual of the MK-61 programmable calculator: keys, stack, programming, indirect addressing, accuracy and power (in Russian).
- Elektronika MK-85 and MK-85M Operating Manual (Russian)
The 66-page operating manual of the MK-85 and MK-85M BASIC pocket computers, with worked examples (in Russian).
- Elektronika MK-85 Circuit Diagram
The circuit diagram of the MK-85 BASIC pocket computer (in Russian).
- Elektronika MK-90 Operating Manual (Russian)
The 56-page Russian operating manual of the MK-90 BASIC pocket computer (in Russian).
- Elektronika MKSh-2 Operating Manual (Russian)
The operating manual of the MKSh-2 school calculator, which ran from a 42 V AC classroom supply (in Russian).
- Elektronika S3-22 Desk Calculator (Russian Book Excerpt)
Three pages on the Elektronika С3-22 desk calculator from a Soviet book on office computing machines, with its keyboard layout and operations compared with the Iskra-111 (in Russian).
- Elektronische Analogrechner
Excerpt (pages 96–98) from the second edition of this German-language textbook on electronic analog computers, Volume 8 of the series 'Mathematik für Naturwissenschaft und Technik'. The excerpt covers Chapter IV on operational amplifiers, specifically §12 (complex-plane computing circuits) and §13 (reversible operational amplifiers), presenting mathematical derivations, node equations, and circuit configurations for reversible inverters, constant multipliers, and integrator-differentiators. Author Prof. Dr. Helmut Adler was Director of the Institute for Machine Computing Technology at the Technical University of Ilmenau; the full work contains 273 figures and 7 tables.
- Elektronischer Analogrechner RA 463/2
Two-page Telefunken product brochure for the RA 463/2 electronic analog computer, describing it as an optoelectronic repetitive-operation machine with variable computing times from 0.1 to 172 seconds. The standard configuration includes 5 computing amplifiers, 1 function generator, 21 function potentiometers, 2 time-base generators, 31 motor-driven coefficient potentiometers, and 5 multipliers housed in one display cabinet and two computing cabinets. The document emphasizes modular construction enabling rapid component replacement and suitability for solving ordinary differential equations.
- Elektronischer Langzeitrechner endim 2000: Programmier- und Bedienungsanleitung
Programming and operating manual for the endim 2000 electronic long-time analog computer manufactured by VEB Rechenelektronik Glashütte (East Germany). Covers machine structure (amplifiers, multipliers, function generators, nonlinearities), operating modes (IC/Idle and Run), programming panel use, control and monitoring procedures, output evaluation with the function recorder, and technical appendix data for amplifiers, potentiometers, comparator, and electronic clock. The machine operates with computing voltages of ±100 V and supports up to 32 integrators/summators configurable from the programming panel.
- Elektronischer Resolver ERV 801 — Bedienungsanleitung für die Zusammenschaltung mit einem Tischanalogrechner RA 742
Operating instructions for the Telefunken ERV 801 Electronic Resolver, an expansion module for the RA 742 desktop analog computer. The 7-page manual describes connection via parallel cable, four operating modes (free inverter amplifiers, multiplier, polar-to-Cartesian conversion, and Cartesian-to-polar conversion), jack color coding, and the small programming panel layout. Reference voltages are ±10 V representing ±180° for angular quantities.
- Elektronischer Resolver ERV 801 — Informationsblatt AiB 010
Two-page German-language information sheet (Informationsblatt AiB 010) for the AEG-Telefunken ERV 801 Electronic Resolver, published 1967. Covers application (polar-to-Cartesian and Cartesian-to-polar coordinate transformation, multiplication, and inverting-amplifier modes selectable by front-panel key), outstanding features (modular plug-in construction, wideband Hall-effect multipliers), and full technical specifications including static errors (sin/cos ≤ 0.1 %, magnitude ≤ 0.2 %, angle ≤ 0.03 %), bandwidths (up to 110 kHz), power supply (220 V / 30 VA), and physical dimensions.
- Elementary Instructions for Operating the Slide Rule, Mannheim Type (K&E, copyright 1928) — pages 1–6 only
The instruction sheet supplied with K&E's beginner's rules, including the 4058C (Jeff owns an original copy with his 4058C). This file is only the six-page identification preview published by Clark McCoy: reading three-figure numbers on C and D, locating numbers with the glass indicator, multiplication (2 x 3, 18 x 26, 72 x 51) and the decimal point. A full scan of Jeff's own copy would replace it.
- Eliminating Obsolete Marking Requirements for Toy, Look-Alike, and Imitation Firearms (NIST, 91 FR 7824, 19 February 2026)
Removes 15 CFR part 272 (the Commerce marking rule), leaving CPSC's 16 CFR part 1272.
- Engineering Applications of Analog Computers
ANL-6319 Rev. is an Argonne National Laboratory report presenting seven worked engineering experiments solved on analog computers, covering reactor control rod deceleration, pressure flow through packed beds, reactor kinetics with thermal feedback, vibrating systems, temperature distribution in fins and slabs, and iodine-xenon buildup in a reactor. Each experiment follows a structured format covering problem description, mathematical statement with constants and initial conditions, machine equation derivation with scale factors, circuit diagrams with potentiometer and static check sheets, and graphical results. The document demonstrates direct analog solution of nonlinear differential equations from nuclear reactor engineering and heat transfer without linearizing simplifications.
- Entwicklungstendenzen im hybriden Rechnen
German-language journal article by W. Giloi of the Technische Universität Berlin, originally presented as a lecture at the AFIPS Computer Exposition (Anaheim, November–December 1967) and published in Elektronik vol. 17, no. 11, 1968. The article surveys the state of hybrid computing as of 1967 — analyzing error behavior of analog versus digital computers, the structure of hybrid systems (ADC/DAC interfaces, crosspoint switch matrices, mode control), and emerging hybrid programming languages such as MIDAS, APACHE, and HYBLOCK. It concludes with a forward-looking prognosis for increasing automation of hybrid programming, larger reconfigurable analog networks, and the eventual migration of more computational work to the digital side.
- Epanechnikov and Tsvetkov, Handbook of Applied Programs for Microcalculators (1988, in Russian)
Spravochnik po prikladnym programmam dlya mikrokal'kulyatorov (Finansy i statistika, 1988, 320 pp): a handbook of applied programs for Soviet programmable calculators (in Russian).
- Epson E0C6200/S1C6200 Core CPU Quick Reference
Quick reference for Epson's 4-bit watch CPU core: memory map, registers, the decimal (BCD) flag, HALT and SLP, and the instruction set with cycle counts.
- Epson S1C60N05 4-bit Single-Chip Microcomputer (product sheet PF912-04)
Product sheet for a 4-bit watch-class microcontroller: S1C6200 core, ROM and RAM sizes, LCD driver and booster, 32 kHz oscillator and trimming, piezo outputs, and µA-level currents.
- Epson Toyocom FC-135 / FC-13F 32.768 kHz Crystal Unit
Datasheet for a 32.768 kHz tuning-fork crystal: tolerance, turnover temperature, parabolic temperature coefficient, motional parameters and ageing.
- Erläuterungen zu der D1A-Reihe Analogrechner
A German-language introductory brochure from Telefunken explaining the principles and applications of the D1A-series analog computers, including the desktop RAT 740 and the precision RA 800 HYBRID system. Covers the basic computing elements (summing/integrating amplifiers, potentiometers, multipliers, function generators, and comparators) with circuit schematics, and illustrates practical application examples in control engineering, mechanical vibration simulation (automobile suspension), electrical engineering (transformer analysis), and process control.
- Ermittlung der Kennwerte eines Prozesses mit Hilfe selbsteinstellender Systeme
A technical paper by Roland Konkart published under the AEG-Telefunken 'Datenverarbeitung — Analogrechner und Hybride Systeme' series, covering four methods for determining process parameters using self-adjusting (adaptive) systems: Gauss-Seidel iteration, iterative gradient, and continuous gradient methods (with both series and parallel models). The document derives the mathematical foundations for minimizing the squared-error objective function, presents analog computing circuit diagrams for each method, and works through a complete example of identifying the coefficients of a second-order system on a hybrid analog computer.
- ES1, LPS and SELV Voltage and Source Requirements Summary
One-page table comparing IEC 62368-1 ES1/LPS with IEC 61140 and IEC 60364 SELV limits (60 V DC).
- Espressif ESP32-S3 Series Datasheet (v2.2)
Dual-core Xtensa LX7 MCU with Wi-Fi and Bluetooth LE; GPIO and ADC limits for the ESP32 alternative to the RP2040.
- Etude sur Simulateur des Régimes Transitoires des Concentrations dans une Installation de Diffusion Gazeuse
CEA Report No. 2010, authored by Delarousse, Trouvé, and Jacques from the Uranium Isotope Separation Studies Service at Saclay. Describes an electromechanical analog simulator built from CSF fire-control computer components to solve up to 35 linear differential equations representing transient isotope concentration regimes in gaseous diffusion cascades. The report covers the mathematical derivation of simulation equations via finite-difference approximation, hardware architecture (functional blocks, 5-rack layout, 472 kc/s HF integrators), accuracy assessments (2% steady-state, 2–10% transient), and practical applications including perturbation compensation, predetermined transitions, and full start-up schedule optimization for a 640-stage uranium enrichment plant.
- Every Man His Own Brewer or A Compendium of the English Brewery
- Evolution of the Strowger Automatic Telephone (chart)
Chart of Strowger telephone/system evolution (image).
- Exidy Crossbow — Preliminary Manual
Optical adjustment test for the crossbow light gun.
- Exponential Functions
A three-page lecture handout reviewing the rules of exponentiation and logarithms before introducing the exponential function f(x) = e^x and the generalized exponential function f(x) = a^x. The document covers graphical properties such as vertical intercepts, horizontal asymptotes, and the behavior of exponential functions for a > 1 and 0 < a < 1, with numerical tables and limit notation. Relevant as mathematical background for analog computer programming involving exponential and logarithmic signal relationships.
- Exposé schématique du fonctionnement des armes de petit calibre (Muller, 1933)
A French Army teaching text with coloured schematic plates explaining the working of every French service small arm of the period, from the Lebel and Berthier rifles to the Chauchat, FM 24/29, Hotchkiss and the 7.65 mm Ruby-type pistol. The Chauchat dive takes its cycle, feed plates (Planches XV–XXII) and the 637 m/s Balle D velocity from it; the Ruby section covers that pistol.
- Extremwertsimulation eines Reglers für blockierungsfreies Bremsen auf dem Hybriden Präzisionsanalogrechner RA 770
A German-language technical article published under the AEG Datenverarbeitung / Analogrechner und Hybride Systeme imprint, describing the simulation of an anti-lock (blockage-free) brake controller using the hybrid precision analog computer RA 770. Authors Coinzel (TELEX, Heidelberg) and Maier (AEG-Telefunken, Konstanz) present the operating principle of the brake controller, the hybrid simulation structure combining the RA 770 analog computer with a digital computer for controller logic, and results of an extreme-value parameter search to optimize controller performance. Simulation results include vehicle velocity and stopping distance comparisons with and without the anti-lock controller.
- F.lli Pietta — Instruction Manual for Muzzleloading (Percussion) Guns, English
Pietta's English instruction manual for its percussion revolvers, including the LeMat model: loading charges and ball sizes, the shot barrel, safety, disassembly and cleaning.
- F.lli Pietta — Revolver Catalogue 2025/26
Pietta's revolver catalogue (pages headed 'Catalog 2025'), including the LeMat reproductions in their current variants.
- FAA Advisory Circular 60-11A: Aids Authorized for Use by Airman Written Test Applicants (1979)
The 1979 rules for navigation computers and electronic calculators in FAA written tests, including memory erasure.
- FAA Advisory Circular 60-11C: Test Aids and Materials (1999)
The 1999 circular allowing 'all models of aviation-oriented calculating devices' in knowledge tests; cancelled 2025.
- FAA Airman Testing Community Advisory, August 2024
Announces the E6-B flight computer built into the knowledge-test platform from 23 September 2024.
- FAA Order 8080.6H, Conduct of Airman Knowledge Tests
The FAA order whose chapter 3 sets the rules for calculators and other aids in airman knowledge tests.
- FAA Pilot's Handbook of Aeronautical Knowledge, Chapter 16: Navigation
The FAA's chapter on navigation (FAA-H-8083-25C), with the wind triangle, flight computers and dead reckoning.
- Facit 1114 Calculator: Reverse-Engineered Schematic
Schematic of the Facit 1114 of 1973: Hitachi HD3276 and HD3253, Toshiba TM4352 drivers, Futaba DG10T tubes.
- Factoring Integers Before Computers (Proc. Symp. Appl. Math. 48, 481–531)
The standard history of mechanical factoring: Carissan, Gérardin, Kraitchik and the Lehmers' sieves.
- Factoring Large Numbers with the TWIRL Device (CRYPTO 2003)
TWIRL, a proposed special-purpose hardware sieve for factoring 1024-bit RSA moduli.
- Factorization of a 768-bit RSA Modulus (IACR ePrint 2010/006)
The RSA-768 factorisation by the number field sieve.
- Faszination Analogrechnen
Lecture presentation by Bernd Ulmann delivered at the 2008 Kolloquium zur Geschichte der Naturwissenschaften, Mathematik und Technik in Hamburg, providing a broad introduction to the history and technology of analog computers. The 132-slide presentation surveys mechanical analog computers (slide rules, planimeters, tide predictors, fire control computers, differential analyzers), early electronic analog computers including Helmut Hölzer's A4 rocket guidance work and Bell Labs fire control developments, electronic computing elements (integrators, multipliers, function generators), programming methods, example problems, and application areas, concluding with an outlook on the future of analog computing.
- Faszination Analogrechnen — Geschichte und Grundlagen elektronischer Analogrechner
A 45-slide German-language lecture presentation by Bernd Ulmann surveying the history and fundamentals of analog computing from mechanical devices (Antikythera, Kelvin tide predictor, differential analyzers) through early electronic machines (Hoelzer, fire control computers) to transistorized systems (Telefunken RA series, EAI machines), hybrid computers, digital differential analyzers, and simulation. The presentation covers computing elements, programming techniques (scaling, normalization, example problems), a broad survey of application domains, and a discussion of why analog computing declined and its potential future role in FPGAs, GPUs, and neuromorphic computing.
- FCC Grant of Equipment Authorization 2ABCB-PICO2W (Raspberry Pi Pico 2 W, DTS)
25 November 2024 grant: 2412–2462 MHz and the 20 cm separation condition.
- FedEx Service Guide 2026 (effective 5 January 2026, updated 11 September 2026)
Carrier terms, including the prohibitions on replica and 3-D-printed weapons.
- Fermented Liquors A Treatise on Brewing, Distilling, and Rectifying
- Fialka M-125: Detailed description of the Russian Fialka cipher machines (Fialka Reference Manual, release 2.0)
Full: history, models, mechanics, circuit diagrams, wheel wiring, accessories, NVA key procedure, repair (144 pp.; free since 2021)
- Fialka Reference Manual addendum: Polish (TEMPEST) power supply unit
BPK-125 TEMPEST PSU as used in Poland
- Fialka Reference Manual addendum: wheel wiring of the 3K, 5K and 6K series (replaces p. 75)
Wiring and blocking-pin positions, Polish, Hungarian(?) and Czechoslovak wheels
- FISH and I
Tutte's 1998 lecture on how he deduced the structure of the Lorenz machine from the depth key, and on the statistical method behind Colossus.
- Flat Panel Multi-Digit Fluorescent Display (SID Digest, 1976)
Ise's paper on its flat nine-digit tube for hand-held calculators: fabrication steps, 2.7 V AC filament, 24 V drive at 1/12 duty, brightness against duty, and a whole-tube power of 39.6 mW.
- Flow Rate Computation: Automatic Dumping Hoppers
A one-page application note (EAI Bulletin ALMP6369-1ob, 1963) describing the use of an EAI PC-12 Process Control Computer to compute flow rates from automatically-dumping hoppers in grinding mill operations. A simple analog circuit computes individual product rates (R = W/t) and fractional production rates, giving mill operators real-time feedback for adjusting grinding parameters. The note includes a circuit diagram for the dumped-hopper computing circuit.
- Fluke 6062A Synthesized RF Signal Generator — Instruction Manual
- FontTweak — Font Conversion Utility Guide
- Forty-Five Pounds of Automatic Navigation
Reprinted from Sperryscope, the quarterly publication of Sperry Rand Corporation, this article describes the AN/ASN-6 Computer Set, Latitude and Longitude — a 45-pound, approximately one-cubic-foot dead-reckoning navigation computer designed and manufactured by Ford Instrument Company (Division of Sperry Rand) for USAF aircraft. The system continuously computes and displays the aircraft's present latitude and longitude by integrating true airspeed, wind speed, wind direction, and heading inputs, and also calculates course and distance to a destination. A supplementary section covers the AN/ASN-7, a follow-on airborne navigation system derived from the ASN-6 that additionally displays rhumb-line course and distance to destination.
- Fowler's "Universal" Calculator — Instructions, with Supplementary Chapters on Logarithmic Calculation and Circular Calculators
The pocket booklet supplied with the 3⅜-in single-dial Universal Calculator (scanned complete, 32 spreads): description of the nine circles (short scale, reciprocals, logarithms, cubes and cube roots on three circles, sines, small-angle sines, tangents), the datum-and-cursor method for multiplication, division, proportion, powers, roots and trigonometry, numerous worked examples, and supplementary historical chapters on logarithms (Napier) and circular calculators. The Hampson Street, Sale imprint under the name Fowler & Co. dates this printing to between the 1938 move to Hampson Street and the wartime change of name to Fowler's (Calculators) Ltd.
- Frank B. Rowlett: A Personal Profile (Cryptologic Spectrum)
Rowlett's own account (from his 1980 memoir material): hiring 1 Apr 1930, Kullback spotting "The Japanese Government" by letter pattern, breaking RED via "oyobi", the six-buster, and Grotjan's 20 Sept 1940 breakthrough at about 2 p.m. (18 pp)
- Frequency-Dependence of Psychophysical and Physiological Responses to Hand-Transmitted Vibration
Open-access review: hand sensitivity peaks around 80–160 Hz and follows velocity; the basis for choosing rumble frequency.
- Friden 1162 Logic Schematic
The logic-level schematic of the integrated-circuit Friden 1162.
- Friden 130 Electronic Calculator Instruction Manual
The 52-page operator's manual for the EC-130: the keyboard, the four-register stack, ENTER and REPEAT, decimal setting, and worked examples.
- Friden 130 Electronic Calculator Sales Brochure (1964)
The six-page launch brochure: the CRT showing four registers, the 11-key keyboard, "no moving parts".
- Friden Calculator Projects 1961-1968
Friden's internal list of calculator development projects from 1961 to 1968.
- Friden Calculator Projects 1961-1979
Friden's list of calculator projects from 1961 to 1979, including the Hitachi-built EC-111x Nixie line.
- Friden EC-130 Field Service Manual (August 1964)
The 51-page field service manual issued at the EC-130's launch: installation, adjustments, fault finding and parts.
- Friden EC-130 Logic Schematic, Four-Counter (Fall 1964)
The one-sheet logic-level schematic of the four-counter EC-130: every gate and flip-flop, without the power supply, delay-line read/write electronics or CRT drive.
- Friden EC-130 Logic Schematic, Three-Counter (late 1965)
The logic-level schematic of the three-counter EC-130.
- Friden EC-130 Master Design Documentation Computer Printout (1964)
Friden's internal Master Design Documentation printout for the four-counter EC-130, version 1: the machine's logic equations as a computer listing.
- Friden EC-130 Service Manual (September 1965)
The 161-page factory service manual for the four-counter EC-130: theory of operation down to gate level, the delay line and its amplifiers, the counters, every keyboard function as a flow chart, the display circuits (segment, dot and staircase generators, slant and deflection amplifiers, diode matrix), the power supplies including the -2,400 V multiplier, and adjustment procedures.
- Friden EC-130 Three-Counter Service Manual Supplement (December 1965)
The 26-page supplement covering the three-counter EC-130 (serial 8501 on), which drops the B counter.
- Friden EC-130/EC-132 Service Letters #1-#35 (1964-1968)
The factory service letters for the 130 and 132, from July 1964 to June 1968: field changes, fault fixes and production changes, including the three-counter change.
- Friden EC-132 Logic Schematic (June 1965)
The logic-level schematic of the EC-132, including the square-root logic.
- Friden EC-132 Master Design Documentation Computer Printout (June 1965)
Friden's internal Master Design Documentation printout for the four-counter EC-132.
- Friden EC-132 Temporary Service Manual (August 1965)
The interim service manual for the EC-132.
- Friden EC-132 Temporary Service Manual: Square Root Mathematics (1965)
How the EC-132 extracts a square root by subtracting successive odd numbers, for service technicians.
- Friden Final Engineering Report: Magnetostrictive Delay Line (June 1964)
Friden's 48-page engineering report on the EC-130 delay line: the Ni-Span C wire, the transducers, the mounting and the measured performance.
- Friden Report on the Victor 3900 (1965)
A 1965 Friden competitive report concerning the Victor 3900 MOS calculator, held by the Old Calculator Web Museum.
- From Muzzle-Loading Cannon and Composite Guns to the Wheel Gun (Wang Zilin, Palace Museum)
A Palace Museum (Beijing) article, in Chinese, on the Qing court's guns, describing the museum's revolving 'wheel gun' (轮子炮) with its eleven-chamber turntable, its measurements and the 1804 inventory record of three presented by Westerners; text page and plate page. The Puckle Gun dive uses it for the Chinese revolving gun as a comparison to Puckle's design.
- Frühe Flugzeugvermessung durch mechanische Rechner bei der Fliegerabwehr: Kurvenflug-Rechner
The eighth in a series of articles by André Masson on mechanical anti-aircraft fire-control computers of the Second World War era. The article examines the challenge of curved-flight extrapolation in mechanical fire-control predictors, presenting the 1935 Fischer 'Denkschrift' and the Bandi 'Memorial Luftschutz' as foundational documents, then describes how curved-flight calculation was eventually realized in the Swiss Gamma-Hasler 43 and the German Wehrmacht Kommandogerät 40. Also covers early Contraves devices (Oionoskop, Stereomat, Verograph) and includes a chronology of the first decade of Swiss heavy anti-aircraft defense through 1945.
- Frühe mechanische Rechner der Artillerie und Fliegerabwehr: Automatisierte Rechner für Geschossflugbahnen
A 24-page German-language historical article by André Masson (2017) examining pre-electronic mechanical analog computers used to calculate artillery and anti-aircraft projectile trajectories. The article surveys historical integrating gear mechanisms (friction-disc, cone, Amsler ball integrator, drum gear), then details two concrete devices: the Fösgen trajectory computer (Rheinmetall-Borsig / TH Aachen dissertation, 1937, possibly never built) and the Curti-Dubois-Amsler ballistic integraph 'Mariandl' (built 1948 by Amsler & Cie. Schaffhausen for the Swiss Army, later rebuilt). Appendices cover pre-electronic muzzle-velocity measurement, a chronology of the Curti device development through 1956, and unresolved technical questions.
- FSTC 381-5012 — Typical Foreign Unconventional Warfare Weapons (U)
Unclassified US Army Foreign Science and Technology Center study (post-1964, undated) of weapons improvised or modified by insurgents. The small-arms section describes two Viet Cong Sten-type submachine guns built around Mk II pattern parts, with photographs — the clandestine-fabrication afterlife of the design. The title page also prints the number as 381-4012.
- Führungsverhalten des vierrädrigen Straßenfahrzeugs bei Regelung des Kurses auf festgelegter Bahn
A 6-page German journal article (Regelungstechnik, Vol. 13, No. 5, 1965) analyzing the guidance behavior of a four-wheeled road vehicle under automatic course control. Drawing on Fonda's vehicle differential equations and classical control theory, the author derives transfer functions for lateral and yaw dynamics, compares mechanical/optical/electrical guidance systems, and shows via analog computer simulation that a lateral-deviation controller is poorly damped. A new controller architecture using curvature difference as the primary control variable eliminates the destabilizing 1/p² geometry element and achieves acceptable stability; FM modulation of the guidance cable supplies curvature set-point information to the vehicle.
- Functions
A three-page introductory mathematics handout covering the concept of real-valued functions and their relevance to mathematical modeling. Topics include the real number system (natural numbers, integers, rationals, irrationals), the definition of a function (domain and range), and four representations of functions: verbal, algebraic/symbolic, numerical table, and graphical. The document concludes with the Vertical Line Test as a method for identifying valid function graphs.
- Functions And Their Graphs
Section 2.1 of the open textbook 'Difference Equations to Differential Equations' by Dan Sloughter, covering the foundational concept of functions and their graphical representations. The section defines functions, domain, range, function notation, composition, and major function classes (polynomials, rational, algebraic, transcendental), with worked examples drawn from physical scenarios. Practical guidance on computer-aided graphing, windowing, and point density is also included.
- Fundamentals of Texture Mapping and Image Warping (Master's thesis, UCB/CSD-89-516)
Berkeley master's thesis, 17 June 1989. The closed-form square-to-quadrilateral projective mapping that OpenFIRE's aiming maths uses.
- FunkAmateur, June 1967 (Soemtron 220 announcement, in German)
The June 1967 issue of the East German magazine FunkAmateur, which announced the zero series of the Soemtron 220 Nixie desk calculator from Sömmerda (in German).
- Fusil à répétition modèle F2 — FRF2: Armée de Terre Identification Poster (2010)
The French Army's one-sheet identification poster for the FR-F2 sniper rifle (SIRPA Terre, 2010), with its characteristics. The MAS FR-F2 dive's first source for the rifle's official data.
- GAU's Analog Calculator: Multiply, Divide, Square, and Extract Roots
A reconstruction and machine-translated English version of a July 1968 article from the Italian magazine Sperimentare describing a simple battery-powered analog calculator built from three wire-wound linear potentiometers and a center-zero microammeter. The device performs multiplication, division, squaring, and square root extraction on numbers from 0 to 10 with approximately 5% accuracy by exploiting the potentiometric null-balance principle, making results independent of supply voltage. The article covers circuit theory, component selection, calibration procedures, operating instructions for all four arithmetic functions, and a retrofit modification using a trimmer and resistor to extend the division range by a factor of ten.
- General Catalog No. 11 — Kellogg Switchboard & Supply Co. (1949)
Complete, 178 pp, OCR. Relays, keys, jacks and cords with AE cross-references; no switching systems
- General Composition of Functions
A three-page mathematics lecture note introducing the concept of function composition, defining g∘f as the combined action of applying f then g to a real-valued input. The document covers composition notation and examples using polynomial, trigonometric, and power functions, then reframes stretches and shifts of functions as special cases of composition. It concludes with techniques for decomposing complex functions into simpler compositions, motivating the chain rule for differentiation.
- General Description and Theory of Operation Model 28 Printer Teletype Bulletin 216B 1953
The primary theory of operation: keyboard, RO base, typing unit (clutches, selector, code bars, type box positioning incl. Fig. 2-43, printing, spacing, functions), motors, cabinet, ESU; 60/75/100 wpm; 20/60 mA. 61 pp
- General Instrument Data Catalog (1976)
General Instrument's 1976 data catalogue, including its C-series calculator chips used in many fluorescent pocket calculators.
- General Instrument Microelectronics — 1977 Data Catalog
608-page data book. The AY-3-8500/8550 'Ball & Paddle' television game chips and their rifle interface (Fig. 7), the light gun of the dedicated Pong consoles. Downsampled to 150 dpi.
- General Power Functions
A lecture note covering the definition and differentiation of general power functions of the form f(x) = x^a for any real number a. The document establishes the identity x^a = e^(a ln x) for positive x, then systematically defines the function for x = 0 and negative x according to the rational or irrational nature of the exponent. The derivative formula d/dx(x^a) = ax^(a-1) is derived with analysis of where the derivative exists, illustrated by several Chain Rule examples.
- General Report on Tunny — the Newmanry History (transcribed by Tony Sale)
The Newmanry part of Bletchley Park's 1945 General Report on Tunny: Heath Robinson, Colossus and the statistical methods, as formatted by Tony Sale in 2001.
- Generating Characters (Electronics, 3 January 1958)
The MIT Lincoln Laboratory article on drawing characters on a CRT from sine and cosine waveforms, the method behind the Wyle Scientific's display.
- Geometry of the Prytz Planimeter (Foote)
The mathematics of the hatchet (Prytz) planimeter.
- George Lasry, "A Practical Meet-in-the-Middle Attack on SIGABA"
Functional description, key-space analysis (2^95.6), survey of prior attacks, MITM known-plaintext attack (2^60.2), MTC3 challenges, reference Java simulator with a test vector (9 pp.) [writer B]
- German Infantry Weapons — MIS Special Series No. 14 (1943)
The US Military Intelligence Service's 25 May 1943 survey of German infantry weapons. The MG 42 dive quotes sections 12 and 13 (M.G. 34 and M.G. 42, pp. 58–94); the Luger P08 dive uses its pistol section (pp. 3–10) for the wartime American description of the P08.
- German Patent DRP 75,837 — Borchardt, Selbsttätige, besonders als Repetirpistole verwendbare Feuerwaffe (1893)
Hugo Borchardt's German patent for the C-93 self-loading pistol, granted from 9 September 1893: full specification and three drawing sheets (Figs. 1–19), including the three-position schematic of the toggle ('Froschgelenk') rising as the breech opens.
- Getting Started with the TI-84 Plus CE Graphing Calculator (2023)
TI's current English and French getting-started guide for the TI-84 Plus CE: keys, modes, MathPrint, graphing, statistics, the Numeric Solver, Press-to-Test, charging and the battery.
- Getting Started with the TI-84 Plus CE Graphing Calculator (OS 5.3)
TI's getting-started guide for the TI-84 Plus CE written for operating system 5.3, including running archived programs and Press-to-Test.
- Getting Started with the TI-84 Plus CE Python Graphing Calculator
TI's getting-started guide for the TI-84 Plus CE Python (OS 5.7): the CE's keys and menus plus the Python app, TI-SmartView CE, charging and Press-to-Test.
- Giga-tronics 6060A Series (6061A/6062A) Synthesized RF Signal Generators — Datasheet
- Giga-tronics 6060A Series Synthesized RF Signal Generators — Manual
- Giga-tronics 6062A Synthesized RF Signal Generator — Instruction Manual
- Giga-tronics 6062A Synthesized RF Signal Generator — Operation & Maintenance (Service) Manual
- Golf Game Computing System (US Patent 3,598,976)
US Patent 3,598,976, patented August 10, 1971, describing an analog computer-based golf game simulation system invented by Jack A. Russell and Bradford J. Baldwin. The system uses sensors to detect the trajectory of an actually-struck golf ball and feeds the measurements into an analog computing circuit that calculates and displays where the ball would land on a real golf course. The patent includes 17 sheets of detailed circuit schematics and system diagrams covering the sensor array, analog computing elements, and display apparatus.
- GP-6 Analog Computer
Four-page product brochure for the Comdyna GP-6 Analog Computer, describing its internal components (8 operational amplifiers, summer resistor networks, inverter networks, electronic switch networks, integrator capacitor sets, 8 coefficient potentiometers, multiplier/divider boards), patch panel design using bread-boarding or PC board fabrication, and ease-of-operation features including an internal DVM digital readout, two-axis address for computed variables, manual and repetitive operation modes, and a visual overload indicator. The brochure also covers interconnections with analog/digital and microcomputer systems, performance specifications (stable roll-off, high FET input impedance, low drift), four time scales per integrator, and applications in laboratory simulation, circuit needs, classroom teaching, and control system design.
- GP-6 Analog Computer Operator's Manual
This combined Operator's and Maintenance Manual for the Comdyna GP-6 analog computer covers operating procedures, operator functions, and patch panel operations. It describes the GP-6's computing elements — summers, integrators, multipliers, dividers, squarers, square-root extractors, differentiators, and track/store units — with schematic diagrams and patch panel wiring instructions. Maintenance sections address coefficient potentiometer calibration, digital voltmeter circuitry, the 982/983 dual multiplier network, and a scaling review example.
- GP-6 Analog Computer Operator's Manual
Complete operator's manual for the Comdyna GP-6 analog computer, covering operating procedures for slow-time and high-speed repetitive modes, readout instrument calibration, coefficient potentiometer setting, patch panel programming symbols and operations, and multi-unit slaving. Includes detailed descriptions of internal assemblies—the 911 Quad Amplifier, 116-2 Power Supply, 933/934 Time Base, 970-1 Overload Indicator, 982 Dual Multiplier Network, and 905 Digital Voltmeter—plus accessories such as the Model 709 Variable Diode Function Generator, Model 771 Transfer Function Simulator, and the 9300-series D/A Electronic Switch banana-plug modules.
- Graduate Engineering Training: U and Y Type Relays — Bell System (1957)
69 pp, OCR (this is the 11 MB copy; the 294 MB original scan was skipped). The 755A is built on U-type relays (BLR 1938)
- Grape Culture, Wines, and Wine-Making
- Graphics in the PicoMite VGA — MMBasic Graphics Paper
- Graphing Calculator Apps Guide for the TI-84 Plus CE-T
Guide to the applications for the TI-84 Plus CE family (CE-T edition, v5.7): Cabri Jr. geometry, CellSheet, Conic Graphing, Inequality Graphing, the Polynomial Root Finder and Simultaneous Equation Solver, and others.
- Graphing Derivatives
A two-page lecture note explaining how to sketch the graph of a derivative function from the graph of the original function. The document covers constant, linear, quadratic, and cubic examples, introducing critical points, inflection points, and concavity as graphical analysis tools. A three-step procedure is presented for constructing a derivative sketch from any smooth function graph.
- GRE PSR-800 EZ Scan-SD Digital Scanner — Owner's Manual
GRECOM PSR-800 EZ Scan-SD Digital handheld scanning receiver owner's manual (2011), as filed with the FCC under FCC ID ADV0602902: controls, EZ Scan library and scanlists, V-Scanner II, recording, SAME weather, discriminator output, specifications.
- GSP 020-000-000 Tools, Apparatus and Test Equipment: index
Index of GT&E practices on tools and test equipment; finding aid for further 26A-family documents.
- GSP 032-210-108 GTE Automatic Electric Cord Assemblies, Eight or More Conductors
Wiring diagrams and stocklists for AE multi-conductor cords, test plugs (D-57038-A, D-57037-A, D-57163-A) and FD-1003/FD-1006 plugs; likely includes the 26A calling cord (D-543536-A candidate).
- GSP 032-320-702 Test Jack Assemblies and Navy Type Shelf Jacks, Adjustment
Adjustment of switch test jacks and shelf jacks; states the standard Strowger switch shelf jack has up to 24 terminals.
- GSP 108-000-000 Numerical Index, Division 108: Central Office Test Equipment, Portable
Index of GT&E practices on portable CO test equipment; finding aid.
- GSP 230-005-702 Strowger Two-Motion Switches, Wiper Adjustment
Wiper adjustment procedure for AE Strowger two-motion switches (file name follows TCI's number; document header reads 230-005-702).
- GSP 230-010-510 Two-Motion Type Reverting Call Switches, Pulsing Test
Pulsing test procedure for two-motion reverting-call switches.
- Guardian Electric T12x13 DC Tubular Solenoid — Datasheet
Pull tubular solenoid: force table at four duty levels, coil table, masses and life.
- Guardian Electric T4x12 DC Tubular Solenoid — Datasheet
Small pull tubular solenoid with its force table.
- Guardian Electric TP6x12 DC Push Tubular Solenoid — Datasheet
Push tubular solenoid, shortlisted for a bore-axis striker.
- Guide on the Use of the German Model P.08 Pistol, Caliber 9mm Parabellum (Century International Arms)
The importer's short guide supplied with surplus P08 pistols: description, operation and care and cleaning. The Luger P08 dive cites it, and notes that its production claims conflict with the factory figures.
- H-580059-A: Selector Circuit, Local or Incoming, Battery Searching, Routiner Access
Circuit drawing of the AE two-motion selector in the collection (stamped DH-580059); Tables A and B list its figures and options.
- H-580156 Selector Circuit, Local and Incoming (issue 6)
AE two-motion selector circuit drawing; directly applicable to wiring a selector stage.
- H-580260 Connector Circuit drawing
AE connector circuit drawing.
- H-85175 Dial Speed Spotter circuit drawing
Circuit drawing companion to E-85175.
- H-856252 Reverting Call Switch, 10-party coded
AE reverting-call switch circuit; the 26A tests these switches.
- H-85919-A Type 26A Switch Tester, Portable Routine Test Set Circuit (sheets 1-2 of 3)
AE circuit drawing for the Type 26A switch tester: full schematic (Fig 1A), remote control set D-322542-A with 15-pin plug, adapter cords, strapping and trip/false-trip tables, key layout. Sheet 3 (calling-cord figures) missing.
- Haff Planimeters 313, 315 and 317: Instruction Manual
The current manual for Haff's compensating polar planimeters, worded almost exactly like K&E's 1957 manual, with the 200 sq in / 2000 sq cm constant circle.
- HAL ST-5000 FSK demodulator keyer manual
HAL ST-5000 FSK demodulator/keyer manual (175 V 60 mA loop; 2N5655 high-voltage keyer; ±15 V FSK output)
- Hand-Book of the Lewis Machine Gun, Model 1918, Caliber .30 (Savage Arms)
Savage's maker's handbook for the American .30-06 Lewis: general description, weights and measurements, dismounting and stripping, assembly, operation, the safety, care and adjustment, with plates. The Lewis Gun dive's main source for the mechanism, takedown and the American guns.
- Handbook of Analog Computation
A comprehensive second-edition handbook covering all major aspects of electronic analog computation, prepared by EAI's Education and Training Department. The 401-page volume addresses mathematical modeling, general-purpose analog computer architecture, programming and problem-checking procedures, linear and non-linear systems analysis, function generation, transfer function and transport-delay simulation, repetitive operation, analog memory, partial differential equations, solution accuracy, efficient programming practices, and laboratory planning. Appendices provide Laplace transform tables, transfer function circuits, diode and relay circuits, and a selected applications bibliography.
- Handbook of Analog Computation
A comprehensive second-edition handbook developed by the EAI Education and Training Department from nearly a decade of intensive short courses in analog computer operation, programming, and applications. The 396-page volume covers the full spectrum of analog computation: linear and nonlinear components, scaling and programming procedures, function generation, transfer-function simulation, transport delay, repetitive and memory operation, partial differential equations, accuracy analysis, and efficient programming case studies. Machine-specific examples reference the PACE TR-20, PACE TR-48, and large-scale EAI 8800 systems, with appendices on Laplace transforms, transfer-function circuits, diode/relay circuits, and an applications bibliography.
- Handbook of Analog Computation (Including Application of Digital Control Logic)
A comprehensive 163-page handbook prepared by Maxwell C. Gilliland (Computer Research, Inc.) and Systron-Donner staff covering analog computation from fundamentals through advanced applications. The 22 chapters span basic computing elements, analog programming techniques, scaling, computer operation, digital control logic, partial differential equations, control system simulation, vector analysis, sampled-data systems, correlation analysis, system optimization, medical applications, and adaptive control. Intended for Systron-Donner analog computer users and seminar participants.
- Handbook of Wines Practical, Theoretical, and Historical
- Handbuch der Praktischen Bierbrauerei
- Handhabung der Hamann Manus R Rechenmaschine (1953)
The factory operating manual for the Manus R, in German, including the back-transfer lever the R added.
- Handhabung der Hamann Manus Rechenmaschine
The factory operating manual for the Manus (a model D is pictured), in German: the controls, addition, subtraction, multiplication and automatic division, with the numbered control map.
- Handy-book for Licenced Victuallers, Brewers, Wine Retailers, etc.
- HCT WJ-1501 Tea Egg Pot — Operation Manual (English)
English translation of the Traditional Chinese operation manual for the HCT WJ-1501, a 5-litre all-stainless-steel separable tea egg pot (全不鏽鋼分離式茶葉蛋鍋) made in Tianwei, Changhua County, Taiwan — the machine that sits on the counter of a Taiwanese convenience store. There is no English edition; this was translated from photographs of the printed booklet and the labels on the machine. Sections 8–17 are the manual as printed: the keep-warm cycle (which cuts all power for thirty minutes and looks exactly like a dead appliance), the thermal cut-out that every one of its four troubleshooting entries resolves to, parts and controls, safety, cleaning, specifications and warranty. Sections 1–7 are added, because the booklet is an appliance manual that assumes you already know how tea eggs are made: what 冷開水 ("cold boiled water") actually means, what the 吸渣布 sediment cloth physically is and that it is a drop lid rather than a filter, how the eggs are cracked at the blunt end to vent the air cell, a walkthrough of both the commercial and the marbled method, scaled marinade ratios, care of the 老滷 kept marinade, and holding times. Those additions are sourced from Taiwanese convenience-store practice and Taiwanese home-cooking sources, listed in the document's own section 18.
- Heathkit IT-1121 Semiconductor Curve Tracer — Manual
- Heathkit IT-3121 Semiconductor Curve Tracer — Schematic
- Heathkit Semiconductor Curve Tracer — Manual
- Heckler & Koch Mark 23 Pistol .45 ACP Operator's Manual (2008)
H&K USA's operator's manual for the commercial Mark 23 (revised March 2007; PDF dated August 2008): safety, description, operation, field stripping, maintenance and the parts list. The HK Mk23 dive takes the controls, takedown, care and part names from it.
- Heckler & Koch Military & Law Enforcement Catalogue (2008)
H&K's US military and law-enforcement catalogue of 2008 ("© HKDCS 01.12.08"). The HK PSG1 dive cites its "HK Precision Rifles" panel (p. 19) for the PSG1 and MSG90 as H&K offered them then.
- Hewlett-Packard Journal, December 1977 (HP-01 wrist instrument)
The issue describing the HP-01, 'Wrist Instrument Opens New Dimension in Personal Information': its six-chip hybrid, power, keyboard, display, case and specifications.
- Hewlett-Packard Journal, June 1972: the HP-35
The Hewlett-Packard Journal of June 1972, introducing the HP-35, with articles on its design, its algorithms and accuracy (Cochran) and its packaging.
- Hewlett-Packard Journal, May 1973 (HP-80)
The issue with 'A Pocket-Sized Answer Machine for Business and Finance', the HP-80's design, including its Newton's-method interest-rate algorithm.
- Hewlett-Packard Journal, October 1977 (HP-92)
The issue with 'Printing Financial Calculator Sets New Standards for Accuracy and Capability', on the HP-92 and its Kahan-based financial algorithms.
- Hewlett-Packard Journal, September 1968: the HP 9100A
The HP Journal issue introducing the 9100A: Osborne on the hardware (CRT display, inductive printed-circuit ROM, core-rope control ROM, core memory), Cochran on the internal programming (number representation, CORDIC-style trigonometry, logarithms), Monnier and Near.
- Hilfsblätter zum Praktikum Analogrechner (Mini-AC)
A German-language laboratory reference handbook produced by RWTH Aachen (Rheinisch-Westfälische Technische Hochschule Aachen) for use with the EAI Mini-AC hybrid analog computer. The 40-page document covers the patchboard layout, component inventory (6 integrators, 3 summers, 3 track-store units, 3 multipliers/dividers, 2 function generators, 18 potentiometers, 3 comparators, and a full digital logic section with 10 AND-gates, 4 J-K flip-flops, counter/timer, and monoflop), and detailed operating principles for all analog, digital-analog, and digital element types including the IC/OP/HD/PP/SP/SL operating modes and repetitive computation timing.
- Hinweise zum Entwurf von Digitalen Schaltwerken bei der Lösung von Optimierungsaufgaben mit dem Analogrechner
A German-language technical article by H. Schrimpe describing the design of digital sequential networks (flip-flop logic) to control analog-computer-based parameter optimization on the AEG-Telefunken DEX 102 (DEX 100) analog computer. The paper derives Boolean switching equations from a flow diagram for one-dimensional optimization with step-size control, uses Karnaugh-Veitch diagrams for logic minimization, and presents the resulting flip-flop control circuits for integration with the analog machine run/hold modes.
- Historie Diehl: Elektronische Rechner
Pages from Diehl's company history on its electronic calculators, including the Combitron of 1966 (in German).
- History of NSA General-Purpose Electronic Digital Computers (Doc ID 6586784)
Declassified NSA history: punched-card prehistory (750 machines by 1945), ATLAS I/II, ABEL, ABNER, BAKER, NOMAD, SOLO, BOGART, IBM 701–7090, HARVEST and TRACTOR, with a dated installation table (105 pp)
- History of the invention and development of the Mark II ECM, pp. 11–14 (NSA REF ID A60492)
Navy account of Friedman's Hebern solutions, Serial 682,096, Rowlett's stepping maze, 1935 disclosures, index maze (5,855 vs 120), 3 Feb 1940 acknowledgement, 'Rowlett is entitled to full credit' (5 pp)
- Hitachi 200D Series Analog/Hybrid Computer
Sales brochure for the Hitachi 200D Series desk-top analog/hybrid computers, covering three models: the 220D (24 amplifiers), 240D (40 amplifiers), and 260D (60 amplifiers). The series features high-speed parallel logic elements (flip-flops, comparators, counters), a 9-inch rectangular CRT display with four-channel simultaneous waveform readout and electronic marker generator, servo-set potentiometers adjustable by external signals for hybrid use, and a modular unit system allowing optional composition scaling. Key component types include dual integrators, dual multipliers, function generators, time delay units, quad electronic comparator/switch, and DA-143 DC amplifiers with overload recovery within 50 microseconds.
- Hitachi 200D Series Analog/Hybrid Computer Specification
Detailed specifications sheet covering the Hitachi 200D series analog/hybrid computers — models BA-220, BA-240, and BA-260 basic analog consoles — along with a comprehensive catalog of computing components including DC amplifiers (DA-141, DA-143), integrator networks (IN-141, IN-143), multiplier networks (EM-141, EM-143), diode function generators (FG series), potentiometers, digital logic modules (comparators, flip-flops, counters, relays), patch panels, and accessory/display devices. Key reference voltages are ±10 V; amplifiers provide 1 MHz bandwidth and open-loop DC gain of 2×10^7 typical; integrator drift is ±100 µV/sec typical. The document is distributed by Hitachi Electronics and Nissei Sangyo Co., Ltd., Tokyo.
- Hitachi 505 Analog Computer
Eight-page sales brochure for the Hitachi 505, an all-transistorized ±100 V desk-top analog computer with built-in digital logic elements for hybrid operation. The brochure covers special features including FET chopper amplifiers, electronic mode-control integrators, a shielded color-coded patchboard, a 4-digit DVM or 3-channel 9-inch oscilloscope readout, a 3-channel timer, and a 2-variable function generator. Physical and electrical specifications are given: console dimensions approximately 32 × 33 × 22 inches, weight around 300 lbs, power 115 V AC 50/60 Hz 500 VA.
- Hitachi 505E Analog/Hybrid Computer
Sales brochure for the Hitachi 505E analog/hybrid computer, a desk-top all-solid-state machine expandable from 10 to 124 operational amplifiers across four standard configurations (505-10, 505-30, 505-60, 505-120). The brochure details outstanding features including 100V operational amplifiers, three-cycle high-speed repetitive operation, color-coded shielded patch panel, servo-set potentiometers, built-in four-channel oscilloscope, and an integrated digital logic package with flip-flops, AND gates, counters, comparators, and mode-matrix for full hybrid computation. Component descriptions cover dual and quad amplifiers (DA-151A, DA-153), RMC and EMC integrator networks, electronic multipliers (EM-151, EM-153), variable and fixed diode function generators, relay comparators, time delay units, and a trunk unit for external digital computer interfacing.
- Hitachi Analog Computer 505 Operation Manual
The complete operator's manual for the Hitachi Analog Computer 505, a solid-state modular analog computer manufactured by Hitachi, Ltd. The manual covers all operating procedures including pre-patch panel insertion and removal, amplifier balance, monitoring and control systems (output selector SL-25A, digital voltmeter DV-25L, mode control), potentiometers, operational amplifiers (DA-151), quarter-square multipliers (EM-151), six types of function generators, comparators, free diodes, transfer delay elements, automatic operator, mode control panel, timers, and repetitive operation. The computer operates on a ±100 V reference and supports multiple computing consoles in a master-slave configuration.
- Hitachi Analog Hybrid Computer HITACHI-200X
Sales brochure for the Hitachi-200X analog hybrid computer, describing a desk-top or rack-mounted machine designed so that the operator patches a block diagram directly on the patch board without requiring knowledge of electronic circuit terms. The brochure covers key innovations including direct block-diagram programming, three ranges of coefficient potentiometers (0.1, 1, 10), a Program Check System (PCS), dual-point shielded patch contacts, IC-based operational amplifiers, and digital coefficient amplifiers for hybrid operation. General and individual specifications are tabulated, application examples spanning linear and nonlinear differential equations, epidemiology, germs-in-water problems, earthquake response, and industrial simulation are illustrated, and a full composition table lists available computing element configurations (A-10, A-20, 2S, 2LS, 3, 3S, 4, 4S, 4LS).
- HITACHI Analog-Hybrid Computer Technical Information Series No.2: Information on Hybrid Interface (2nd edition)
This Technical Information Series No.2 (2nd edition) provides detailed specifications for linking the HITACHI-505 analog computer to a digital computer via a hybrid interface. It covers interface signal requirements, input/output channel configurations, multiplexer and A-D converter performance specs (±10V range, 0.1% accuracy, sign+binary 10-bit output code), and the serial BCD protocol for remotely setting servo-set potentiometers (SP) and servo-set function generators (SFG) from the digital side. Connector pin-out tables and system block diagrams for the hybrid linkage are included.
- Hitachi HD3100 Series PMOS Calculator IC Data Sheets
Data sheets for Hitachi's HD3100-series PMOS chips used in the Friden EC-1114/1115, Casio 121-B and other Japanese Nixie calculators: shift registers, gates, flip-flops and the serial adder.
- HK Personal Defense Weapon — 4.6 × 30 mm PDW Weapon System (Schatz, H&K Inc., 2000)
An H&K Inc. presentation on the PDW system ("Revised 12/00"), with product-comparison slides of November 2000 using prototype data. The HK MP7 dive cites it for H&K's case for the 4.6 mm cartridge during the NATO PDW contest.
- How Many Days in an Egyptian Year? Evidence from the Antikythera Mechanism
Horological Journal, April 2024. The calendar-ring hole count and the Egyptian year.
- How to Brew with three-fourths Barley to One Fourth Malt
- How to Mix Drinks, or the Bon Vivant s Companion
- How to Play Dr. NIM (instruction manual)
The Dr. NIM instruction manual: 15 marbles, and whoever takes the last one loses.
- How to set the keys (and card) — guide to the punched-card editor of the Fialka Windows simulator
Screenshots and steps: index bar, setup window, punched-card edit window (clear card, insert triangle, print, apply)
- How to Use Dual Base Log Log Slide Rules (Pickett Form M-15)
Pickett's dual-base log-log manual, c.1960 printing of the 1947 text (yellow-logo cover, Chicago and Santa Barbara). Covers the split square-root and cube-root scales, the CF/M and DF/M scales, double T scales, vector methods, the dual-base (+/-) log-log scales, and hyperbolic and circular functions of complex arguments. The manual for the N3's square-root, cube-root and two-T-scale layout. ISRM notes this copy came with an N16-ES.
- How to Use Log Log Slide Rules (Pickett Form M-14; reference for Models 800, 803, 300, 600 and N3, with the 803 supplement)
Pickett's standard log-log manual (copyright 1953): reading the scales, multiplication and division, decimal point, CI/CF/DF, A-B squares and roots, K cubes, L logarithms, S, T and ST trigonometry, elementary vectors, and the log-log scales (powers, roots, e^x, logs to any base), with practice problems and answers. The ISRM scan names the N3 and Model 600 among the rules it served. 74 pp (37 sheets).
- How to Use Rotary Stepping Switches
AE handbook on rotary stepping switches (Type 44/45) and circuits.
- How to Use Trig Slide Rules
The student instruction manual for the Pickett trig rules — illustrated with the Model 1010 Trig and Model 902 Simplex Trig, the two student rules most often reproduced as demonstrators. Part 1 slide-rule operation (reading the scales, multiplication, decimal point, division, continued products, proportion); Part 2 special scales (CI, DI, CF, DF, CIF, A/B, K, L, S, T, ST, combined operations); Part 3 trigonometry applications (law of sines, vectors, solving triangles); Part 4 the principles (logarithmic scales explained). Every procedure transfers directly to the matching 4-ft or 7-ft wall rule.
- HP 12c Financial Calculator User's Guide (Edition 5, 2008)
HP's user's guide (0012C-90001, Edition 5, April 2008) for the ARM-based 12C: RPN, percentages, dates, TVM, amortization, NPV/IRR, bonds, depreciation, statistics, programming, solutions and Appendix D formulas.
- HP 12C Platinum Owner's Handbook and Problem-Solving Guide (2003)
Handbook for the 12C Platinum, with its algebraic mode and 400-line program memory.
- HP 12c Quick Start Guide (2008)
HP's short getting-started guide for the 12c.
- HP 48SX Owner's Manual, Volume I
Volume I of the owner's manual for the HP 48SX of 1990 (edition 4, July 1990).
- HP 48SX Owner's Manual, Volume II
Volume II of the owner's manual for the HP 48SX of 1990 (edition 4, July 1990).
- HP 9100A Calculator Brochure (1968)
Hewlett-Packard's launch brochure for the 9100A.
- HP 9100A Operating and Programming Manual
The owner's manual for the 9100A (09100-90001): the keyboard, the X, Y, Z display registers, storage registers, programming and magnetic cards.
- HP 9100A Training Manual
Hewlett-Packard's training manual for the 9100A.
- HP 9100A: Trinity College Dublin Computer Collection Catalogue Entry
A detailed catalogue entry on the 9100A: board list, control and program ROMs, microword format, core memory and internal photographs.
- HP 9100A/B Calculator and Peripherals Technical Data (1969)
HP's October 1969 technical data sheet (5952-2119) for the 9100A and 9100B and their peripherals: the 9120A printer, 9125A plotter, 9160A marked-card reader and 9150A display; speeds, numerical format, programming, memory and keyboard.
- HP 9100A/B Interfacing Manual (09100-90031, 1970)
Hewlett-Packard's February 1970 manual for connecting peripherals and instruments to the 9100A and 9100B through their I/O connectors, with a caution that improper signals can severely damage the calculator.
- HP 9100A/B Service Manual (09100-90034, 1971)
Hewlett-Packard's January 1971 service manual for the 9100A and 9100B: pseudo-hardware problems, performance assurance, troubleshooting (verify the problem, check the CRT, troubleshooting tree), assembly locations, the standard and optional supply and deflection-amplifier schematics, waveforms, replaceable parts and backdating. 110-page black-and-white scan.
- HP 9100A/B Service Manual (09100-90034, 1971), Colour Scan
A second, high-resolution colour scan of the January 1971 9100A/B service manual (91 pages), with the covers.
- HP 9100B Microprogram Flowcharts
The algorithmic-state-machine flowcharts of the 9100B's microprogram: the nearest thing to its ROM listing in public.
- HP 9100B Operating and Programming Manual
The owner's manual for the 9100B (09100-90021), with its doubled memory and subroutines.
- HP 9100B Program Library (1969)
HP's library of 9100B programs for science, engineering, statistics and finance.
- HP 9100B Schematics
Factory schematic sheets for the HP 9100B: logic boards, flip-flop boards, side-board expanders, card reader and supplies.
- HP 9100B Schematics, Redrawn by Tony Duell
Tony Duell's hand-drawn schematics of the HP 9100B, traced from a working machine: power supplies, CRT and deflection circuits, logic and the other boards, 182 pages.
- HP 9125A Plotter Service Manual (1970)
The service manual for the 9125A X-Y plotter used with the 9100.
- HP 9160A Marked Card Reader Operating Manual (1969)
The operating manual for the 9160A card reader peripheral of the 9100.
- HP-01 Owner's Guide
Hewlett-Packard's 106-page owner's guide (00001-90001, Rev. C, May 1977) for the HP-01 wrist instrument: time, alarm, stopwatch, calendar and the interactive calculator.
- HP-01 Quick Reference Guide
Two-page quick reference (00001-90002, Rev. B, August 1977) for the HP-01's key sequences.
- HP-12C Owner's Handbook and Problem-Solving Guide (Edition 2, 1992)
The classic 12C handbook (00012-90001, Edition 2, January 1992), 252 pages.
- HP-12C Solutions Handbook (1987)
HP's handbook of ready-made 12C programs and procedures for real estate, lending, investment, leasing, securities and statistics (Rev. F, July 1987).
- HP-12C Training Guide (1984)
HP's 1984 training course for the 12C, with exercises.
- HP-28C Getting Started Manual
Edition 3 (March 1987) of the getting-started manual for the HP-28C, Hewlett-Packard's first graphing calculator (part 00028-90001).
- HP-35 Operating Manual (1972, red dot)
Hewlett-Packard's operating manual for the first-version (red dot) HP-35 (00035-90008).
- HP-35 Operating Manual (1973)
Hewlett-Packard's operating manual for the HP-35, August 1973 edition.
- HP-41 IC Specifications (Nut CPU and related chips)
HP's internal specifications for the HP-41 integrated circuits, including the Nut CPU used in the Voyager calculators.
- HP-65 Aviation Pac 1
Hewlett-Packard's HP-65 aviation programs: flight planning, weight and balance, wind and conversions.
- HP-65 Navigation Pac 1 (1974)
Hewlett-Packard's magnetic-card programs and manual for navigation and dead reckoning on the HP-65.
- HP-75 Owner's Manual
Hewlett-Packard's owner's manual for the HP-75C portable computer (00075-90001).
- HP-80 Owner's Handbook
Owner's handbook for the HP-80 of 1973, the first financial pocket calculator, with its calculation formulas.
- HP-80 Problems Booklet
Worked financial problems for the HP-80.
- HP-92 Investor Owner's Handbook (1977)
Owner's handbook for the HP-92 printing financial calculator of 1977.
- HSE-Analog-Computer: Eine Neuentwicklung für die biomedizinische Forschung
A four-page German sales brochure (dated 1.1.1977) for the HSE Analog Computer, a medium-scale analog computer designed specifically for biomedical research applications such as pharmacokinetics and cardiovascular physiology. The machine provides 32 integrators, 32 summers, 16 multipliers, 8 function generators, and 32 coefficient potentiometers at approximately 1% computational accuracy, targeting a price point below large mainframe computers. The brochure includes a detailed component list, pricing in Deutsche Mark (DM 54,100 fully equipped), and a worked pharmacokinetics programming example demonstrating substance transport among stomach, blood, and urine compartments.
- Hybrid Computer System Request for Proposal
A January 1966 Request for Proposal (RFQ) issued by Lockheed Missiles & Space Company (LMSC) for the procurement of a hybrid computer system. The document defines detailed technical requirements for the analog section, covering minimum component counts for five identical computing systems, including operational amplifiers, integrators, summers, potentiometers, multipliers, resolvers, and electronic switches. Intended to solicit competitive bids from computer manufacturers for a high-accuracy hybrid computing facility to support Lockheed's aerospace simulation work.
- Hybrid Computing at Ames Research Center: The Ames Linkage System and the Digital Logic Simulator
NASA Technical Memorandum TM-X-50975 from Ames Research Center describes two hybrid computing systems developed at the Center: the Ames Linkage System, which couples a remote analog simulator to a digital computer over 2500 ft of coaxial transmission lines for reentry vehicle flight simulation, and the Digital Logic Simulator (DLS), a general-purpose logic computing element placed in service September 1962. The paper details the Data Acceptance Routine (DAR) for efficient time-sharing of the digital computer between production work and simulation runs, and presents three DLS applications including heartrate computation from ECG data and probability distribution determination using hybrid techniques.
- Hybrid Computing at Lockheed
Control Data Corporation application report describing Lockheed Missiles Systems Company's hybrid computing laboratory, which combines four CDC 8400 analog computers with a CDC 3200 digital computer. The system is used for missile trajectory simulation, Polaris submarine navigation studies, and other aerospace/defense problems requiring high-speed repetitive solutions. The brochure covers system configuration, operating software, and the advantages of hybrid computation over purely analog or digital approaches.
- Hybrid Precision Analog Computer System RA 770 D — Operating Manual, Part 1
Part 1 of the operator's manual for the AEG-Telefunken RA 770D Hybrid Precision Analog Computer System, covering introduction, computer design and equipment, operating and control procedures, and programming. The RA 770D is a high-precision hybrid analog/digital computer featuring silicon-planar transistor amplifiers, low-drift operational amplifiers, and a modular drawer-based chassis expandable with additional computing units. The manual is organized into sections covering mechanical layout, computing elements (integrators, summers, multipliers, non-linear networks), operating controls, and programming techniques.
- Hybrides Rechnersystem HRS 860 — Kurzbeschreibung
Brief description (Kurzbeschreibung) of the AEG-Telefunken HRS 860 Hybrid Computing System, which combines the TR 86 digital computer with the HKW 860 hybrid coupler network and the RA 770 (or RA 860 H) precision analog computer. Covers system architecture, operating modes (preparation, computation, output phases), hardware components including DA/AD converters (14-bit, ±0.01% LSB, 16 or 32 channels), and the software stack comprising the BESY 70/75/76 operating system, VEPRO traffic-control program, FORTRAN-HYBRID compiler, TST860 diagnostics, and VAMPIR potentiometer-logging utility.
- Hybridsysteme: Automatisches Skalieren und statischer Test mit dem hybriden Interpreter HOI; Echtzeitsimulationen
A collection of German-language articles from the journal Angewandte Informatik covering EAI hybrid computer systems. The primary paper by K. Schwarze describes the HYTRAN Operations Interpreter (HOI), EAI's standard hybrid software, with emphasis on automatic amplitude/time scaling, off-line and on-line static testing, and automatic control of hybrid programs, demonstrated on a third-order ODE with variable coefficients using the EAI-690 system. Additional articles address hybrid computing in computer science education and real-time simulation of cable/rope mechanical systems and flight vehicle guidance.
- HYDAC Hybrid Digital-Analog Computer Series 2000
A promotional brochure for the EAI HYDAC (Hybrid Digital-Analog Computer) Series 2000, a general-purpose computing system combining analog and digital operations in twin control consoles. The system incorporates proven PACE 231R analog computing components alongside modular digital building blocks providing logic, memory, arithmetic, and conversion functions; five major groups of digital components are available including programmed digital logic, analog memory, digital-to-analog and analog-to-digital conversion, and advanced digital arithmetic units. The brochure highlights application areas including partial differential equations, optimization, simulation of logic functions, and high-speed hybrid computation.
- Hynetek HUSB238A USB PD EPR Sink Controller — Datasheet (Rev 1.1)
Alternative EPR sink; its fallback rule is quoted.
- IATA Battery Guidance Document — Transport of Lithium Metal, Lithium Ion and Sodium Ion Batteries (Revised for the 2026 Regulations)
Air transport rules for shipping packs and kits.
- iCopy-X Firmware Update Guide — ICopyX
- iCopy-X RFID Badge Cloning Device — Product Overview
- iCopy-X RFID Cloner — User Manual
- iCopy-XS RFID Cloning Device — Lab401 Product Page
- iCS Decoder for iCLASS SE / SEOS — Product Page
- Il calcolatore analogico di GAU: moltiplica, divide, eleva al quadrato ed estrae radici
A hobbyist article describing the construction and theory of a simple three-potentiometer analog computer originally published in the Italian magazine Sperimentare (July 1968, "Archimede, calcolatore elettronico") under the initials GAU. The device uses a 9 V battery, two 10 K and one 1 K wire-wound potentiometers, and a centre-zero microammeter to perform multiplication, division, squaring, and square-root extraction on numbers from 0 to 10 with approximately 5% accuracy. The reproduction adds a trimmer-and-resistor retrofit (DIV x10 mode) for quotients exceeding 10, provides step-by-step calibration and operating procedures, and derives the underlying potentiometric-bridge mathematics.
- ILC1-8/8LV Multi-Digit Fluorescent Indicator Datasheet (in Russian)
Label sheet for the Soviet ILC1-8/8LV flat multi-digit fluorescent tube, a relative of the calculator ILC1-8/8L: 5 V filament, 35-50 V segment and 30-40 V grid pulses, -7 V grid cut-off (in Russian).
- Illustrated Instructions
Illustrated Instructions for Changing M15 and M20 Teletype Gears
- IME 26 Instruction Manual
The instruction manual for the IME 26 commercial calculator: keyboard, registers, basic operations, constants, chain calculations and worked commercial examples.
- IME 84 Calculator: Reverse-Engineered Schematic
A 26-page schematic of the IME 84 of 1964: germanium DTL, core memory, decade counters and the 16-digit multiplexed Nixie display, with a board list (408 transistors, 1,045 diodes).
- IME 84 Calculator: Theory of Operation
A 33-page theory of operation of the IME 84: the 20 kHz clock and digit cycle, core read and write, decade-counter arithmetic, the procedures for each key, and notes on replacing germanium parts (BAT46, 2N3906, MPSA92).
- IME 86S Calculator: Reverse-Engineered Schematic
A 27-page schematic of the IME 86S, the IME 84's successor: discrete germanium logic, core memory and Nixie display.
- IME 86S Calculator: Theory of Operation
A 34-page theory of operation of the IME 86S, written from the reverse-engineered schematic.
- Imperfect Forward Secrecy: How Diffie-Hellman Fails in Practice (Logjam, ACM CCS 2015)
Logjam: number-field-sieve precomputation used to break weak Diffie-Hellman groups in practice.
- Implicit Functions
A five-page calculus lecture note covering the definition and properties of implicit functions, with worked examples drawn from conic sections (ellipses, parabolas, hyperbolas). The note develops the technique of implicit differentiation — treating y as a function of x, differentiating both sides of a relation, and solving for y′ — and identifies 'bad points' where the derivative formula is undefined, corresponding to vertical tangents.
- In Praise of Ale
- IN-12 Nixie Tube — Datasheet
- IN-14 Nixie Tube — Datasheet
- IN-14, IN-17 and Related Nixie Tubes: Reference Table (in Russian)
A reference table of Soviet gas-discharge indicator tubes, including the IN-14 used in the Iskra desk calculators: striking and maintaining voltages, supply and brightness (in Russian).
- IN-16 Nixie Tube — Datasheet
- IN-18 Nixie Tube — Datasheet
- IN-8-2 Nixie Tube — Datasheet
- Infineon EZ-PD CCG3PA USB Type-C Port Controller — Datasheet (002-16951 Rev *H)
Source-side controller, covered as a 'why not'.
- Infineon IPD50N06S4L-12 OptiMOS-T2 60 V N-Channel MOSFET — Datasheet (Rev 1.0)
Logic-level 60 V, 12 mΩ DPAK MOSFET; the reference solenoid switch.
- Influence of U.S. Cryptologic Organizations on the Digital Computer Industry (Cryptologic Spectrum 1977–78, reprinted Cryptologic Quarterly)
Unclassified article on how SIS/OP-20-G punched-card work, ERA, ATLAS, ABNER, SOLO and HARVEST fed the commercial computer industry (18 pp); precursor of Snyder's 1980 Annals article
- Information from Documentary Evidence on Messages No. 901, 902, 907, 910 (the 14-part message)
Interception, decryption and delivery times for the Japanese pilot message, the 14-part message and the "1 p.m." message of 6–7 December 1941. NSA REF ID A488471.
- Injoinic IP2721 Type-C/PD2.0/PD3.0 Input Physical Layer IC — Datasheet (V1.02)
The common 'decoy' chip.
- Inspection Checklist: Fake, Toy, or Imitation Guns (NYC DCWP, 08/2022)
NYC Administrative Code § 10-131(g) as the inspectors enforce it.
- Installation of No. 755A PBX Lamp Circuits (addendum to 550-550-210) — AT&T BSP 550-550-210 Addendum
2 pp. The only 755A BSP in TCI's 550 folder that the Library lacked
- Instruction Manual for Analogue Computer SCD 10
Instruction and maintenance manual for the Solartron SCD 10 Analogue Computer, a general-purpose medium-capacity machine intended as a design tool or educational aid. Covers technical description of control panel, patch panels, and reference power supplies; installation and test procedures; and breakdown instructions with component lists. The SCD 10 features differential equation solving, servo multipliers, resolver connections, and a repetitive timer suited to problems such as servomechanism analysis and automatic control.
- Instruction Manual: Model 3103 Dual DC Amplifier (Chopper-Stabilized) and Model 3732 Electronic Multiplier (Quarter-Square Type)
Two bound instruction manuals for Donner Scientific Company (a division of Systron-Donner Corporation) analog computer plug-in units. The Model 3103 (August 1960) covers the Dual DC Amplifier using chopper-stabilization, including specifications, installation, operation, circuit description, servicing, parts list, and schematic (Drawing No. 5217). The Model 3732 (July 1961) covers the Electronic Multiplier using the quarter-square technique, providing similar operator and maintenance reference material for use with Donner 3000-series analog computers.
- Instruction Manual: Model 3500 Analog Computer (Portable)
Instruction manual for the Donner Model 3500 Portable Analog Computer, manufactured by Donner Scientific Company (a division of Systron-Donner Corporation) in January 1960. Covers computer theory (including an outline for non-electronics personnel), programming and operation, circuit description, servicing, and a parts list, with appendices containing schematic diagrams, demonstration problem connections, tech notes, and a potentiometer loading chart. The 49-page manual addresses both the portable bench configuration and rack-mount installation of the Model 3500.
- Instructional Notes on the Lewis Gun — RAF F.S. Publication No. 37 (1918)
The Royal Air Force's April 1918 instructional notes on the Lewis gun as an aircraft weapon. The Lewis Gun dive cites it for the air-service guns and their handling.
- Instructions — Precision Slide Rule No. 2/83N, 62/83N with enlarged scale range
English text of Faber-Castell's owner's instructions for the 2/83N Novo-Duplex and its pocket twin the 62/83N: the full 31-scale list with formulas, reading the 25 cm and 50 cm (W) scales, C/D, CI/DI, A/B, K, folded and Pythagorean P scales, trig S/T1/T2/ST, complex numbers, the W root scales and their black/red index rules, the L mantissa scale, the eight LL scales, cursor marks (d/q circle area, kW/PS, 3.6) and care of the rule. Retyped transcription (not a page scan) with the original diagrams omitted.
- Instructions for Brewing Porter and Stout at an Expense of 4d and 5d per Gallon
- Instructions for Managing Bees
- Instructions for the Use of Fowler's Vest Pocket Calculator (Long Scale) — List 33V
The four-page folded leaflet for the 2½-in double-sided Long Scale vest-pocket calculator. Describes the front dial (outer 'short scale' 6.7 in in circumference plus a six-circle 'long scale' 30 in long) and the seven back-dial scales (multiplying scale, reciprocals, logarithms, square roots twice round, log sines 5°45'–90°, log tangents 5°45'–45°, small-angle log sines 35'–5°45') with their graduation intervals; the 'Datum' line, 'Cursor', top nut X and side nut Y; multiplication, chained factors, division and a/b÷m by the set-datum / set-cursor-to-1·0 / turn-dial method; gauge points; mensuration and trigonometry examples. Converted to PDF from the museum's single high-resolution scan of the two open spreads (2 PDF pages).
- Instructions for the Use of the Fuller Calculator (Models No. 1, No. 2 and Fuller-Bakewell)
Stanley's instruction booklet for Professor Fuller's calculators with a 41 ft 8 in (500 in) logarithmic scale: description of cylinder, inner cylinder and handle, the fixed index F and movable indexes A and B, adjusting the index bar (pivot screw, tightening screw, cam), the multiply/divide 'bring' and 'set' sequence with worked examples, decimal-point rules by characteristic, Model No. 2 logarithm and sine scales, the Fuller-Bakewell tacheometry scales with a field-book example, and tables of data. Includes the box-as-stand illustration.
- Instructions sur L art de Faire la Biere
- Integer Sequences Having Prescribed Quadratic Character (Math. Comp. 24, 433–451)
Pseudosquare searches run on the Lehmers' electronic sieves, with the machines' role described.
- Integration of Rational Functions (Section 6.4)
Section 6.4 of Dan Sloughter's open calculus text 'Difference Equations to Differential Equations' covers the integration of rational functions using partial fraction decomposition. The section treats distinct linear factors, repeated linear factors, and previews irreducible quadratic factors (deferred to Section 6.5 on the inverse tangent). Worked examples and a problem set are included.
- Intel 1402A/1403A/1404A Dynamic Shift Registers (1976 Data Catalog)
Intel 1402A/1403A/1404A dynamic shift registers — 1976 Intel Data Catalog pages 4-2 to 4-6; metal-can (M1404A) pinout used to check the KENBAK-1 reproduction board.
- International Rectifier IRLZ44NPbF Logic-Level HEXFET MOSFET — Datasheet
55 V logic-level TO-220 MOSFET; the breadboard-stage switch, with its RDS(on) points.
- Introduction to Electronic Analogue Computing
An experiment manual prepared by Argonne National Laboratory (ANL-6187) to introduce participants in the International Institute of Nuclear Science and Engineering to electronic analogue computing. Covers general theory of electronic analog computers (operational amplifiers, integrators, differentiators, servo multipliers, servo dividers, differential relays), operational information for the Electronics Associates PACE computer, analog programming techniques, and worked experiments including sine-wave generation, xenon buildup in a reactor, reactor kinetics, and isotopic abundance in fast reactors.
- Introduction to Simulator (Part 1)
The first part of Hitachi's Technical Information Series No. 9 introduces simulator applications for civil and structural engineering problems using analog and hybrid computers. It covers flood prediction methods including the storage function, unit graph, and outflow function approaches, showing how the governing differential equations are implemented on analog hardware. A second major section describes earthquake response simulation using the SERAC (Strong Earthquake Response Analysis Computer) analog computer, treating linear and non-linear single- and multi-mass-point vibration models of high-rise buildings; the SERAC system comprises integrators, special integrators, adders, inverters, potentiometers, function generators, and voltage comparators.
- Introduction to Simulator (Part 2)
The second installment of Hitachi's Technical Information Series No. 10 surveys four analog-computer simulation applications: pipe network flow analysis (using electrical analogs of the Hazen-Williams and Williams-Hazen equations), voice synthesizers (spectrum-analysis and configuration-analog methods), nerve-cell and nervous-system models, and cardiovascular/respiratory system simulators. Each topic is supported by circuit diagrams and block diagrams illustrating how the Hitachi analog-hybrid computer is programmed to represent the corresponding physical or biological phenomena. The document serves as an introductory survey of biomedical and engineering simulation capabilities available on Hitachi analog-hybrid equipment.
- Investigation of Heat Transfer by Conduction
A two-page EAI educational applications note (Bulletin No. ALAC 64135) describing the analog simulation of one-dimensional heat conduction through a metal rod on the PACE TR-20 General Purpose Analog Computer. The system is modeled using a second-order central-difference approximation to the diffusion equation, dividing the rod into five equally spaced segments to yield a set of scaled ordinary differential equations. The note provides system equations, a computer diagram, and potentiometer and amplifier assignment sheets.
- Ise Electronics Itron DG-12C Numerical Indicator Tube Datasheet (June 1968)
Datasheet of the single-digit DG-12C fluorescent tube: filament 0.85 V at 95 mA, segments 25 V and grid 20 V typical, grid cut-off -4 V, segment cut-off 0 V, 80 foot-lamberts, dimensions and pinout.
- Ise Electronics Itron DG-19 Numerical Indicator Tube Datasheet (February 1968)
Datasheet of the single-digit DG-19 fluorescent tube: filament 1.6 V at 95 mA, segments 25 V and grid 20 V typical, ratings and dimensions.
- Ise Electronics Itron DG12B Datasheet
Datasheet of the DG12B, the first mass-produced vacuum-fluorescent tube, used in the Sharp CS-16A: ratings, characteristics and outline.
- Ise Electronics: Development and Commercialization of the VFD (case study, in Japanese)
A business-history case study of Ise Electronics and the vacuum-fluorescent display: Tadashi Nakamura, Sharp, the Burroughs Nixie royalties, production growth and licensing (in Japanese).
- Iskra 110 Operating Manual (Russian)
The operating manual of the Iskra 110 electronic keyboard computing machine (in Russian).
- Iskra 111 Operating Manual (Russian)
The operating manual of the Iskra 111 desk calculator, from the Orel Plant of Control Computing Machines, Ministry of Instrument Making (in Russian).
- Issue of Converter M-209 to Foreign Nations (Army memorandum, 17 February 1949)
Memorandum on supplying the M-209 to Turkey and Latin American forces through military aid. NSA REF ID A66689.
- It Wasn't All Magic: The Early Struggle to Automate Cryptanalysis, 1930s–1960s (United States Cryptologic History, Special Series vol. 6; 2013 MDR release via governmentattic)
NSA CCH history of US cryptanalytic machinery: OP-20-G/SIS IBM tabulators, Bush's Comparator and the RAM program, Navy/Army bombes, Copperhead, Slide Run, ERA, Atlas, Abner, Harvest (362 pp, 48 MB, text layer present)
- ITU-R Recommendation BT.470-6 — Conventional Television Systems (11/1998)
Line and field timing tables for the NTSC, PAL and SECAM systems that CRT light guns time against.
- IV-4 (IV-4) Fluorescent Indicator Tube Datasheet, Sheet A (in Russian)
Datasheet of the Soviet IV-4 eighteen-segment fluorescent tube: filament 2.2-2.9 V at 50 mA, 25-27 V static and 50-70 V pulsed drive (in Russian).
- IV-4 Fluorescent Indicator Tube Datasheet, Sheet B (in Russian)
Second sheet of the Soviet IV-4 fluorescent tube datasheet (in Russian).
- Jadard JD9365DA-H3 — a-Si TFT LCD Single-Chip Driver Datasheet
- Jadard JD9365DA-H3 — User Guide (Preliminary v0.00)
- Jak vznikl Škorpion: žádost o vývoj (Pazdera, Střelecká revue, January 2022)
The first page (the only one online) of David Pazdera's Střelecká revue article on the Škorpion's origin: the one-page requirement for a 7.65 mm weapon of about a kilogram, 250 mm folded, 100 m useful range, firing single shots and bursts. The Škorpion vz. 61 dive translates it.
- JANAP 161 Directory of Communication-Electronics Equipment Part 2 Joint Army-Navy-Air Force Publication 16 1956
JANAP 161, Directory of Communication-Electronics Equipment, Part 2 (Change 1)
- Japan Defense Agency Budget Overview, Fiscal 2000 (防衛力整備と予算の概要)
The Defense Agency's budget overview for fiscal 2000; its Ground Self-Defense Force front-line equipment table ("(6) 正面装備予算総括表") gives the 9 mm machine pistol buys for FY1999 and FY2000. Cited by the Minebea PM-9 dive for the procurement count. Image-only.
- Japan Defense Agency Budget Overview, Fiscal 2001 (防衛力整備と予算の概要)
The Defense Agency's budget overview for fiscal 2001, with the same front-line equipment table (13 guns). Cited by the Minebea PM-9 dive. Image-only.
- Japan Defense Agency Budget Overview, Fiscal 2002 (防衛力整備と予算の概要)
The Defense Agency's budget overview for fiscal 2002; p. 34 gives the 9 mm machine pistol buy (56 guns). Cited by the Minebea PM-9 dive.
- Japan Defense Agency Budget Overview, Fiscal 2003 (防衛力整備と予算の概要)
The Defense Agency's budget overview for fiscal 2003; p. 24 gives the last 9 mm machine pistol buy (27 guns). Cited by the Minebea PM-9 dive.
- Japan Defense Agency Budget Overview, Fiscal 2004 (防衛力整備と予算の概要)
The Defense Agency's budget overview for fiscal 2004; its front-line equipment table shows no 9 mm machine pistols that year, which with the earlier overviews gives the dive's total of 266 guns for FY1999–FY2003.
- Jeppesen E6B Flight Computer Manual (1966)
Jeppesen's manual for the mechanical E6B: slide-rule side, wind side and worked problems.
- Jeppesen E6B Flight Computer Manual (undated)
A later Jeppesen manual for the mechanical E6B.
- Jinlong G1040003D LRA Coin Vibration Motor — Product Specification
Bilingual specification with the LRA test jig and its figures.
- John Hurt — A Translator Extraordinaire (Cryptologic Spectrum)
Tribute to the SIS's Japanese linguist 1930–1963, with the table of the six 1930 hires and their start dates (4 pp)
- Julian Weyers, "Kryptoanalyse der SIGABA" (MA thesis, in German)
SIGABA history and mechanism, a daily key-list example, CrypTool 2 implementation and presentation, cryptanalysis with pseudo-rotors, MTC3 challenge [writer B]
- Kane Mark 6 Dead Reckoning Computer Instructions (1958)
Instructions for the Kane Mark 6 dead reckoning computer, an E-6B-type slide-rule computer.
- KENBAK-1 Installation and Maintenance (1971)
Setting up, care and maintenance of the KENBAK-1.
- KENBAK-1 Laboratory Exercises (1971)
The graded programming exercises supplied with the KENBAK-1.
- KENBAK-1 Programming Reference Manual (1971)
The KENBAK-1 instruction set, addressing modes, registers and front-panel operation.
- KENBAK-1 Programming Worksheets (1971)
Coding sheets and the octal instruction card for the KENBAK-1.
- KENBAK-1 Reproduction Board — Silkscreen / Parts Placement (kenbak.com)
Component-side silkscreen of the KENBAK 10000 REV.B reproduction board (the board Artem Kalinchuk sells), for finding part positions.
- KENBAK-1 Theory of Operation (1971)
How the KENBAK-1's TTL logic and shift-register memory work, state by state.
- Keyboard Matrix — Schematic (2022-08-16)
- KIM-1 User Manual (MOS Technology 6500-15B, August 1976)
Setting up and operating the KIM-1: keypad and monitor, the teletype and cassette interfaces, the memory map, and the timer and I/O.
- KIM-1/6502 User Notes, Issue 0 (complimentary issue)
The first issue of the KIM users' newsletter.
- Kinematic Evaluation of the Special Purpose Individual Weapon Prototypes — BRL Technical Note No. 1541 (1964)
A Ballistic Research Laboratories note of August 1964 measuring the mechanical cycle of the SPIW prototypes. The Hyper-Burst Mechanisms dive cites it for the burst rates and timing the prototypes achieved.
- Know Thy Foe: A New Contender (HP-41C and Sharp PC-1211)
Valentin Albillo's period comparison of the HP-41C programmable calculator and the Sharp PC-1211 pocket computer.
- Know Your Weapons No. 5 — Sten and Bren Guns (Nicholson & Watson)
A 16-page wartime Home Guard booklet from the Nicholson & Watson 'Know Your Weapons' series: labelled cutaways and plain-language notes on the STEN and the Bren for civilian volunteers. Operator level, not engineering.
- Kommandogerät der Fliegerabwehr mit vereinfachter Geometrie, 1938–1950: Ein sog. "Winkelgeschwindigkeits-Gerät"
An 11-page German-language technical article by André Masson (2016) describing the simplified angular-velocity fire-control computer (Kommandogerät) developed by the Swiss Federal Arms Factory W+F and manufactured by HASLER AG for the 34 mm anti-aircraft cannon from 1938. The article details the mechanical gear train, cam bodies, stepped-gear angular-velocity input, telephone-impulse-technique (TIT) data transmission to the guns, and manual correction mechanisms, along with a chronology of the device's operational use in Switzerland (1938–1942) and its eventual replacement. This is the fifth in a series of articles by the same author on WWII-era Swiss anti-aircraft mechanical analog computers.
- Konami Lethal Enforcers — Operators and Service Manual (UK)
UK manual (part no. 9A200) with an optical-gun troubleshooting table.
- Krieghoff Parabellum 2006 Limited Edition — Catalogue Sheet (English)
Krieghoff's one-page catalogue sheet for the 200-piece 2006 Parabellum (serials 18001–18200), with the firm's own wartime production figures (about 13,850 Model 08 pistols 1934–45, about 1,650 civilian). The Luger P08 dive notes that its barrel length and weight disagree with the manual's.
- Krieghoff Parabellum P08, Caliber 9mm — Instruction Manual (English)
Krieghoff's maker's manual for its new-production 2006 Limited Edition Parabellum P08 (200 pistols): safety, the mechanism, stripping, a function check and general data. The Luger P08 dive quotes its warning that the dismantled pistol can fire when the sear bar is pushed, and compares its data with the catalogue's.
- Krieghoff Parabellum P08, Kaliber 9mm — Bedienungsanleitung (German)
The German edition of Krieghoff's manual for the 2006 Limited Edition Parabellum P08, kept alongside the English edition the Luger P08 dive quotes.
- Kunstfolien-Kondensatoren — Fertigungs-Übersicht
Product overview brochure from Dipl.-Ing. Kurt Schümann for the CKS series of plastic film (Kunstfolien) capacitors, covering round-wound and printed-circuit cast versions. Documents voltage ratings (63–630 V DC), capacitance ranges, tolerance options as tight as ±0.1–0.2%, three PCB mounting styles, and general electrical specifications including temperature range −10 to +70°C and isolation resistance ≥ 3 Tera-Ohm. Intended for developers requiring precision custom C-values outside standard catalog offerings.
- Kurzbeschreibung des Präzisionsschützengewehres PSG 1 (Heckler & Koch)
H&K's German-language short description and operator's booklet for the PSG1 (46 printed pages, scanned as two-page spreads): description, technical data, handling and care. The HK PSG1 dive translates its technical data and description.
- Kurzbeschreibung: Hybrider Präzisionsanalogrechner RA770
A German-language illustrated brochure providing a comprehensive overview of the AEG-TELEFUNKEN Hybrid Precision Analog Computer RA770, a fully transistorized 10V machine of 0.01% accuracy class capable of expanding to 142 computing amplifiers, 10 comparator amplifiers, and 84 coefficient potentiometers across up to 3 linked units. Covers computing elements (integrators, summers, multipliers, function networks, comparators, digital elements), programming fields, operation and control features including the digital supplement for automated run sequences, input/output peripherals (digital voltmeter, oscilloscope, XY plotter), construction, applications, technical data, and connectivity to the AEG-TELEFUNKEN TR86 digital computer via the HKW860 hybrid coupling unit.
- Kurzgefasste Bedienungsanleitung fur den Telefunken Analogrechner RA 770
An abbreviated operating guide (48 pages, April 1971) for the Telefunken RA 770 analog computer system, covering startup procedures, insertion of pre-programmed Analog Program Files (APP), operation of the central control unit, computing element control, potentiometer settings including time base and 4-quadrant configuration, and an overview of computing elements such as integrators, summers, multipliers, resolvers, and variable function generators. The RA 770 supports hybrid operation with a DEX 802 digital voltmeter readout and two-computer parallel operation (main computer HR and sub-computer NR). Based on study paper No. 551 by R. Abenhold and intended as a condensed companion to the full Telefunken operating manual.
- L art de Brasser Traduit de L anglais
- L-com BU2HF-2824BK USB Bulk Cable Specification (Rev A)
Construction of the proposed USB lead (WP-4).
- Le Calculateur Analogique Universel "DJINN"
Three-page French sales brochure for the DJINN universal analog computer manufactured by Laboratoires R. Derveaux of Boulogne-sur-Seine. The brochure promotes the machine to engineering design offices across fields including aviation, ballistics, electronics, and atomic energy, emphasizing its modular and demountable construction, interchangeable elements, patching board with visual block-diagram display, and low operating cost. Amplifier specifications given include an open-loop gain of 500,000, 1 W output (plus or minus 100 V into 10 kilohms), automatic zero return, input-referred drift below 0.3 mV, and input grid current below 10 to the -11 A.
- Learn About Analog Computers: Reprints from Hydrocarbon Processing
A collection of reprinted articles from Hydrocarbon Processing (Gulf Publishing, 1969) by Gadmon and Smith of the University of Maryland, covering analog computer theory and practice for chemical and petroleum engineers. Topics span from introductory component identification (potentiometers, high-gain amplifiers, integrators) through magnitude and time scaling, simulation of dynamic systems, nonlinear function generation, algebraic solutions, and hybrid computation. The series addresses practical programming and application to process engineering problems such as distillation, reactor optimization, and multi-tank dynamics.
- Learn BASIC: A Guide to Programming the TI Compact Computer 40
David Thomas's guide to programming the TI CC-40 in BASIC.
- Ledex Box Frame Size B14 Linear Solenoid — Datasheet
Duty-cycle voltage table and force-stroke chart for a small box-frame solenoid.
- Ledex Solenoids Catalogue, Section H — Open Frame Solenoids
Catalogue section with the design considerations (duty cycle, life, pole faces, temperature) plus the open-frame range.
- Let Us Demonstrate How the Du Pont 310 Curve Resolver Reduces Complex Curves to Component Peaks Quickly and Inexpensively
A one-page advertisement from Du Pont Instruments promoting the 310 Curve Resolver, a compact analog instrument that decomposes complex overlapping curves (from chromatography, electrophoresis, NMR spectroscopy, X-ray diffraction, and similar techniques) into individual component peaks. The operator works directly with the instrument's up to ten function generators to match synthetic peak shapes to the original curve on an oscilloscope screen, with the algebraic sum displayed simultaneously. An optional X-Y plotter and integrator are mentioned for recording and area measurement.
- Lethal Enforcers — Instruction Booklet (Super NES, US)
Justifier setup and troubleshooting, with the gun's specification JE507-S01 (5 V, 15 mA).
- Letter on the history of E.S.R., Inc. (March 2000)
An E.S.R. founder's first-hand account of how Digi-Comp I was invented, made and sold.
- Lewis Gun Mechanism Made Easy, 6th edition (Pridham, 1940)
A British instructional booklet on the Lewis gun's mechanism and stoppages, sixth edition with notes on the .300 (American) Lewis guns issued to the Home Guard in 1940, with a coloured plate. The Lewis Gun dive uses its sections and Tables A and B for the cycle and the immediate-action drills.
- LightGunVerter — Instructions
The only manual for a published light-gun timing box: cables, delay, white level and calibration.
- Lightning Calculator: Collection Record (FAU ISER)
The Erlangen computer-science collection's record of a Grand Rapids Lightning D-3 on its wooden base: 7 digits, 33 × 9 × 5 cm, 720 g with the stand.
- Lightning Observing — Turn Your Oscilloscope into a Storm Scope
- Limits And The Notion Of Continuity
Section 2.3 of Dan Sloughter's open calculus text 'Difference Equations to Differential Equations,' covering the formal definition of limits for real-valued functions, one-sided limits, limits at infinity, and the notion of continuity. The section introduces the Heaviside function and piecewise examples to illustrate discontinuities, derives limit laws for polynomials and rational functions, and treats vertical and horizontal asymptotes via limit notation. Eighteen pages of exposition and problems are included.
- Linear Technology AN88 — Ceramic Input Capacitors Can Cause Overvoltage Transients
Hot-plug ringing of a supply lead into a ceramic input capacitor.
- Linear Technology LTC4425 Linear SuperCap Charger with Current-Limited Ideal Diode — Datasheet (Rev A)
Two-cell supercapacitor charger with balancing, current limit and an ideal diode; the USB-powered supercap path.
- Lloyd's 310 Calculator: Reverse-Engineered Schematic
Schematic of the Lloyd's 310 pocket calculator with a nine-digit fluorescent tube.
- Lloyd's Accumatic 55 Calculator: Reverse-Engineered Schematic
Schematic of the Lloyd's Accumatic 55 (also labelled EH-8715) pocket calculator with a nine-digit fluorescent tube.
- Log Log Duplex Decitrig Slide Rule No. 4081: A Manual (1955 printing)
The owner's manual supplied with the K&E 4081 Log Log Duplex Decitrig (and the 4181-3 and 4181-1) made after 1955, the scale set of Jeff's 4081-3 s/n 640904. Copyright 1943, 1945, 1947, 1955. Six chapters: multiplication and division (incl. DF/CF folded scales); proportion and combined operations (CI, CIF); squares, cubes and roots; trigonometry with the S, T and SRT scales and solution of triangles; the log-log scales (LL0x/LLx, powers, roots, e^x, logarithms to any base); and logarithmic theory, with exercises and answers. 132 pp., image scan without text layer.
- Logarithmic Functions and Their Properties
A four-page calculus course handout covering the definition and properties of logarithmic functions of the form f(x) = log_a(x), including domain, asymptotes, and intercept behavior. It derives the differentiation formula d/dx(log_a x) = 1/((ln a)x) and applies the Chain Rule to composite expressions such as ln(x^2), ln(sin x), and ln|x|. The treatment is introductory and pedagogical, aimed at a first-year calculus audience with no specific analog-computer machine context.
- LogicData TA-9 Calculator: Reverse-Engineered Schematic
Schematic of the LogicData TA-9 pocket calculator of 1972 with a fluorescent display.
- London Complete Art of Cookery also The Complete Brewer Explaining the Art of Brewing Porter, Ale, Twopenny, and Table-beer
- LT1236 Precision Reference
Datasheet for the LT1236 precision buried-zener voltage reference IC, available in 5 V and 10 V versions. Key specifications include ultra-low drift of 5 ppm/°C maximum, 0.05% output accuracy, greater than 100 dB ripple rejection, and output current sourcing/sinking of up to 10 mA in series mode. The document covers electrical characteristics, typical performance curves, applications information (trimming, capacitive loading, Kelvin connections), and typical application circuits for A/D and D/A converters, precision regulators, strain-gauge conditioners, and temperature sensors.
- Luger FAQs (Luger Forum and Jan Still Forum, 2019)
A collectors' compilation of answers on Luger makers, markings, variants, production and books, last updated 1 August 2019 and distributed free by the Luger Forum. The Luger P08 dive uses it as an attributed secondary for makers, dates and markings.
- M-125 Nutzung (operating instructions for cipher machines M-125-3MN and M-125-MN)
Full German original: key packages, daily/message keys, message format, enciphering, deciphering, destruction rules
- M28 Gear sets collector compilation 2000
Gear-set part numbers by speed and unit code for LAK, TD bases, LPR, ASR. 1 p
- Machine Gun MG3 Operator's Manual, Cal. 7.62 mm × 51 (Rheinmetall, 1992)
Rheinmetall's English-language export operator's manual for the MG3, the post-war 7.62 mm NATO MG 42: description, field stripping, operation, barrel change, stoppages and care. The MG 42 dive takes its mechanism, maintenance and barrel-change procedure from it.
- Magnavox Odyssey Shooting Gallery — Instructions (1972)
Instructions for the Odyssey Shooting Gallery and its Electronic Rifle, the first home light gun: game cards 9 and 10, overlays, room lighting.
- Maintenance Tools, Bulletin 540
AE tool and test-set catalogue; p.24 shows the Switch Tester Type 26 (Portable) H-883635-1 with panel and jack drawings, plus switch test plugs (D-541784-A) and cords.
- Maintenance Tools, Technical Bulletin 150-540 (issue 10)
Later AE maintenance-tool catalogue: Strowger adjusting tools, gauges, test sets and test plugs by H/D part number.
- Maintenance Tools, Technical Bulletin 150-540 (later GT&E issue)
Different issue of TB 150-540 (later GT&E cover); same tool catalogue content, useful for cross-checking part numbers.
- Making IT Work — Proceedings (British Computer Society / TNMOC, May 2017)
Conference proceedings on keeping historic computers working: conservation versus operation, power-up, repair and documentation.
- Marking of Toy, Look-Alike, and Imitation Firearms — Direct Final Rule (CPSC, 88 FR 30226, 11 May 2023)
Creates 16 CFR part 1272; traces the rule from 15 CFR 1150 to 272 to 1272.
- Martin-Marietta Aerospace Simulation & Test Laboratory
Describes Martin-Marietta's Simulation & Test Laboratory (STL) Man-in-the-Loop Simulation System (MLUS), which uses a hybrid computer arrangement of three Sigma 5 digital computers and six EAI 231-RV analog computers to simulate the AAH (YAH-64), A-10, and F-16 aircraft. The system features an 80x40-foot terrain model scaled at 225:1 (helicopter) and 1200:1 (fixed-wing), a 6-DOF motion base with 18,000 lb payload capacity, and optical probe/TV systems for real-time closed-loop 6-degree-of-freedom simulation of air-to-surface weapon delivery missions.
- Mauser C96 — US Patent 584,479 (1897)
Original US patent drawings for the C96 firing mechanism and lockwork.
- Mauser-Werke Drawing 1MD06-61, "Griffschale, linke" — P08 Left Grip (1939)
A 1:1 Mauser factory drawing of the P08's left grip panel in black laminated paper-phenolic ("Papierschichtpreßstoff Typ Z3 schwarz"), drawn 29 June 1939, checked 7 December 1939 and changed 20 June 1941. The Luger P08 dive uses it to date the black plastic grip against the collectors' "approved mid-1941".
- Mean Well GST120A Series 120 W Industrial Adaptor — Specification
Desktop AC-DC adaptor family; notes -V tied to FG on the DIN-plug version.
- Mean Well GST60A Series 60 W Industrial Adaptor — Specification
Desktop AC-DC adaptor family: overload trip band and hiccup recovery, DC plug and cable options, floating output.
- Mean Well GST90A Series 90 W Industrial Adaptor — Specification
Desktop AC-DC adaptor family; source for the 2.5 mm standard DC plug.
- Mean Well NSP-75 Series 75 W Enclosed Power Supply — Specification
Enclosed supply with a peak-power rating (35 % duty, 5 s) relevant to solenoid pulse loads.
- Mechanical Integrators, Including the Various Forms of Planimeters (Shaw, 1886)
Hele Shaw's survey of planimeters and integrators of every kind known in 1886, with their theory.
- Mechanische Analog-Computer für schwere Flab-Kanonen, ca. 1930–1945: Technische Studien ab historischen Quellen — Funktionsweise des mechanischen Analog-Rechners SPERRY (USA)
A detailed German-language technical study by André Masson of Langenthal examining the internal workings of the Sperry mechanical analog director computer (ca. 1930–1945), acquired on a trial basis by the Swiss Army in 1935. The document explains the follow-pointer operating principle, the polar-to-rectangular coordinate conversion mechanism, cam-body (Formkörper) function solvers, disk integrators, and the electrical servo loop used for iterative impact-point prediction, with comparisons to German (Kommandogerät 36 and 40), British (Vickers), and Hungarian (Gamma-Juhász/Hasler) fire-control directors. The study is based on inspection of the surviving museum specimen at the Flieger-Flab-Museum Dübendorf and on Alfred Kuhlenkamp's 1943 book "Flak-Kommandogeräte."
- Mechanische Rechner der Fliegerabwehr, frühe Lösungen: Flugzeugvermessung im 1. Weltkrieg und danach, ca. 1915–1936
A 34-page German-language research article by André Masson (October 2017) examining early mechanical fire-control instruments for anti-aircraft defense from roughly 1915 to 1936. The article covers the Auswanderungsmesser 17 (lateral deviation meter) and its associated command disc used to compute shell lead angles, a patented Swedish triangulation device (Reich Patent 374514, 1917), an early mechanical angular-velocity/lead-angle calculator (Reich Patent, January 1917), and Swiss experiments with a 7.5 cm Krupp gun on a rotating tower mount. It analyses the geometry of the instruments, identifies unresolved puzzles in the eyepiece grid design of the AM 17, and discusses why these WWI-era devices were still being manufactured under Nazi-era production codes in the early 1940s.
- Mechanisches Rechnen mit präzis geformten Stahlkörpern und Zahnrad-Getrieben
A 2015–2016 research article by A. Masson investigating 143 negative-transparency numerical tables held at the Museum für Kommunikation, Bern, which document HASLER's ballistic cam-body (Formkörper) calculations prepared for the Italian anti-aircraft gun 90/53 circa 1950–1951. The article describes the operating principle of three-dimensional cam bodies and gear mechanisms in mechanical fire-control computers (GAMMA-JUHASZ and GAMMA-HASLER), analyzes whether the five sets of tables correspond to known Swiss HASLER command instruments, and includes appendices on air resistance, ball integrators, and the chronological development of HASLER devices.
- Messages from GCCS to SSA about the CCM, March 1945, with an introduction by Ralph Erskine
The CCM's short-cycle (338) flaw and "lobsters" (2 pp.) [writer A]
- Methodik der rechnergestützten Simulation — Fachgespräche vom 10.–11. Mai 1973
Proceedings of a May 1973 German-language workshop on computer simulation methodology, jointly organized by the Kernforschungszentrum Karlsruhe and the University of Stuttgart (report KFK 1845, 425 pages, 33 contributed papers). Topics span real-time simulation of time-continuous systems, hybrid analog-digital simulation architecture (including HYBRIDMASTER mode control and SCALE/CSMP/MUNICH/DYNAMO programming systems), validation of discrete and continuous simulation models, Monte Carlo methods, and diverse application domains including road traffic, reactor technology, telecommunications networks, satellite attitude control, and human-vehicle systems.
- MFJ-461X Series RF/Cable Feed-Through Panels — Manual
- Microchip ATmega328P microcontroller
- Microchip ATtiny212/214/412/414/416 Data Sheet (DS40002287A)
Datasheet for the ATtiny412 used in each sieve module of kbsriram's Tiny Sieve.
- Microchip HV5812 20-Channel High-Voltage VFD Driver Datasheet
Datasheet of the HV5812 serial-input 20-output driver for vacuum-fluorescent displays, with outputs to 80 V.
- Microchip MCP4728 12-Bit Quad DAC with EEPROM — Datasheet (DS22187E)
The DAC in proposal AH-5 (emulating gun potentiometers).
- Microchip MCP73831 Li-ion charge controller
- MICROSTORE Model 2.395 — Product Information Release (PIR 6219)
A six-page Product Information Release (PIR 6219) from Electronic Associates, Inc. describing the MICROSTORE Model 2.395, a completely integrated solid-state accessory for the PACE 231R Analog Computing System. The unit provides high-speed tracking, storage, and switching of analog data points using solid-state electronic gates with a total switching time under 5 microseconds, and supports real-time and repetitive operation modes determined entirely by patching. Specifications include ±10 V outputs, up to 10 track-and-hold gate inputs, 200 V/µs slew capability, and a control comparator with 10 mV differential sensitivity; the release also surveys general applications such as curve fitting, boundary value problems, optimization, and stagewise simulations.
- Midway CarnEvil — 2-Player Dedicated 25" Operation Manual 16-40069-101
November 1998 manual: the screen-flash brightness setting for the optical guns.
- Midway Terminator 2: Judgment Day — Operations Manual 16-40009-101
December 1991 manual: gun assembly A-14415, its potentiometers, recoil coil and calibration.
- Miida MC1214 Calculator: Reverse-Engineered Schematic
Schematic of the Miida MC1214 desk calculator of 1972 with an Ise DP127F twelve-digit fluorescent tube.
- Miida MC800 Calculator: Reverse-Engineered Schematic
Schematic of the Miida MC800 of 1971: Omron ALPHA1-3 chip set, discrete A628A PNP drivers to -58 V, NEC LD8027 single-digit tubes, lamps for minus and overflow, inter-digit blanking.
- Miida MC840 Calculator: Reverse-Engineered Schematic
Schematic of the Miida MC840 desk calculator of 1972 with an Ise DP82A eight-digit fluorescent tube.
- Mike Douglas 60ma Teletype Loop Driver schematic Rev A April 2022
Mike Douglas, *60ma Teletype Loop Driver*, schematic Rev A, April 2022 (regenerative snubber: T2 low side, D3 into C1/C2, U1 solid-state relay dumps them at mark; T1/L1/D2 optional boost)
- Mike Douglas ASCII RS-232 AFSK Interface
Mike Douglas, *ASCII/RS-232/AFSK Interface for the Model 15 Teletype* — user manual
- Mike the Microtron — InterfaceAge Magazine Article (April 1977)
- Mike Watts (WY6K) — NanoVNA Tips for New and Prospective Users
- Military Cryptanalysis, Part I: Monoalphabetic Substitution Systems (War Department, OCSigO)
Friedman's training text: frequency distributions tallied on cross-section paper, word patterns and "idiomorphism" (DIVISION = ABCBDBEF), probable-word method (76 pp scan; OCR misreads the 1938 imprint as 1918)
- Military Cryptanalysis, Part III: Simpler Varieties of Aperiodic Substitution Systems
SIS training text, Part III (64 pp); complements writer B's Part I
- Military Cryptanalysis, Part IV: Transposition and Fractionating Systems
SIS training text, Part IV (112 pp)
- Miniature Automatic Telephone Exchange (G. C. Goddard) — Wireless World, Feb 1972, p. 90 (1972)
3 pp. A hobbyist's private uniselector exchange
- Minispace Analogue Computer Operational Manual
Operational manual for the Solartron Minispace analogue computer, published by The Solartron Electronic Group Ltd, Thames Ditton, Surrey, England. Covers basic analogue computing techniques, machine setup and programming, patching, coefficient potentiometers, and computer functions including integrators and differentiators. Appendices provide specifications of the DC Amplifier AME1.8 and notes on computer limitations; applications addressed include solving single and coupled differential equations, servo-mechanism simulation, and weapons control system modelling.
- Mitteilungsblatt der EAI Electronic Associates GmbH, Nr. 008, Juli–August 1966
Issue No. 008 (July–August 1966) of the EAI Electronic Associates GmbH customer newsletter announces analog computer training courses in Aachen for October and November 1966, and reports on the EAI Symposium held in Munich in June 1966 covering TR-48/58, DES-30, and hybrid systems. The bulletin also introduces six new VARIPLOTTER X-Y recorders (Types 1120–1133, DIN A3/A4 formats) and the new Series 6.681 compact computing amplifiers (four variants: high-speed op-amp and differential DC amp, ±15 V supply, 25 mA output, epoxy-encapsulated at 52×25×25 mm), with full specification tables and DM pricing. Class-B (refurbished) PACE TR-48 and TR-20 systems are noted as available for purchase.
- Mitteilungsblätter EAI Electronic Associates GmbH, Nr. 005 (Jan.–Febr. 1966)
Issue No. 005 of the EAI Electronic Associates GmbH (Aachen) customer newsletter for January–February 1966, written in German. The newsletter covers the Brush Mark 280 two-channel ink recorder (35 Hz bandwidth, 0.5% accuracy, 80 mm channel), squaring and square-root circuit configurations using EAI parabola multipliers on the TR-48 and TR-20 with a detailed table of wiring options, and a technical introduction to the DES-30 Digital Extension System for hybrid computing with TR-20 and TR-48 analog computers. Additional items include announcement of 1966 analog computing courses in Aachen, the MC laboratory connector system, Heinzinger high-voltage power supplies, and the EAI high-speed printer type 6.610.
- MoD FOI Reply 2017/07603 — SA80 A2 Unit Cost (2017)
The Army Secretariat's reply of 17 August 2017 to a Freedom of Information request on the unit cost of the SA80 A2. Cited by the SA80 dive.
- MoD FOI Reply 2017/09121 — SA80 A2 Upgrade Cost and A3 Initial Tranche (2017)
Defence Equipment and Support's reply of 15 November 2017 to a Freedom of Information request on the cost of the A2 upgrade and the first tranche of the A3. Cited by the SA80 dive.
- MoD FOI Reply 2020/03296 — L85 Fleet (2020)
The Army Secretariat's reply of 5 May 2020 to a Freedom of Information request on the L85 fleet. Cited by the SA80 dive.
- Model 14 15 19 and 28 gear tables collector compilation
Gear numbers for 14/15/19/28 units. **Second tag:** Teletype-Model-15
- Model 28 equipment specifications Teletype typed specification sheets
Sizes, weights (ASR ~260 lb), standard and optional features. 21 pp
- Model 28 keytops list —
Keytop part numbers. 2 pp
- Model 3500 Analog Computer
Sales brochure for the Systron Donner Model 3500 Analog Computer, a compact 28-pound desktop unit designed for instruction, data reduction, signal generation, and process control. The machine features 10 stabilized plug-in amplifiers, a problem board with diode modules, single- and ten-turn potentiometers, regulated ±105 V power supplies, and a front-panel metering system; priced at $1,985. The brochure covers the system's components, specifications, application areas, accessories (including the Model 3530 Problem Board and Model 3570/3571 Potentiometer Strips), and basic installation configurations.
- Modelling Dynamic Economic Problems on an Analog Computer
This EAI bulletin (No. ALAC 65087) by Alfred Engel and John J. Kennedy presents the theory and mechanization of dynamic economic models on analog computers, contrasting analog-friendly continuous differential-equation approaches with finite-difference sequence models. It covers non-genuine and genuine lags, open systems, forced-goal (boundary-value) problems, policy-decision mechanization using comparators and function switches, and the use of track-and-store amplifiers and VDFGs — illustrated with circuit diagrams for Samuelson's Second Interaction Model and Leontief's two-sector lag system. The EAI TR-20, PACE 231R-V, and HYDAC 2400 hybrid system are cited as representative hardware.
- Models 701 and 709 Variable Diode Function Generators
Single-page product brochure for the Comdyna Models 701 and 709 Variable Diode Function Generators (VDFG). The Model 701 features fixed breakpoints with adjustable slopes and 11 straight-line segments for approximating arbitrary non-linear curves, priced at $165; it includes an internal inverter amplifier so segments can be positive or negative, with functions generated across all four quadrants. The Model 709 extends the capability with both adjustable breakpoints and adjustable slopes, offering 5 positive and 5 negative breakpoints each adjustable anywhere within the full 10 V range, enabling 21 or more segment curve approximations, priced at $205.
- Modern Electronic Package for the Wang 300 Series Consoles: Manual
Bob Alexander's manual for his PIC32 board that brings a Wang 300 keyboard console to life without the original electronic package: installation, keyboard and Nixie testing, cathode poisoning, the Wang emulation, a GPS clock and an RPN calculator.
- Molicel INR-18650-P28A Lithium-Ion Cell — Product Data Sheet (V2-80093)
The reference Li-ion cell for the battery dive.
- Monroe 920 Service Manual
The 116-page service manual for the Monroe 920 electronic calculator.
- Monroe 925 Calculator: Reverse-Engineered Schematic
A 17-page schematic of the Monroe 925 of 1970, with delay-line memory and multiplexed JRC B-5755 Nixies.
- Monroe 925 Logic and Timing Manual
Monroe's logic and timing manual for the 925 Nixie calculator.
- Moon Landing Game
A five-page construction article from Practical Electronics (November 1978) describing a small analog computer game that simulates a lunar module descent. The circuit uses operational amplifiers to model the physics of the lander — computing velocity, altitude, and fuel consumption in real time — while the player controls the rocket motor to achieve a soft landing. The article covers the schematic, component list, PCB layout, panel wiring, and calibration procedure.
- MOS Technology TIM and KIM — Book Chapter (Section 1.5, 1975–1976)
- Mostek Calculator Chips: Advertisement
A Mostek advertisement for its single-chip calculator circuits.
- Mostek Integrated Circuit Guide (1974)
Mostek's 1974 catalogue of MOS integrated circuits, including its MK50xx calculator chips, descendants of the MK6010 made for Busicom.
- Moticont Linear DC Motors (Voice Coil) — Comparison Table and Data Sheets
Stroke, force and mass figures for Moticont voice-coil linear motors, the candidates for a moving ejection port.
- Motor Control Units Used with 14 and 15 Teletypewriters - Description and Principles of Operati BSP Section 572-007-100 1964
Motor Control Units Used with 14 and 15 Teletypewriters — Description and Principles of Operation
- Motorola AN-851 — MC6845 CRTC Simplifies Video Display Controllers
A low-to-high edge on LPSTB latches the refresh address into R16/R17.
- Moveable Interactive Projected Displays Using Projector Based Tracking (UIST 2005)
Projector-based tracking at about 12 Hz with hidden patterns.
- MP7 A1 — Innovation for the Future: Brochure (Heckler & Koch, c. 2007)
H&K's earlier 16-page MP7A1 sales brochure (image PDF dated 2007), with the parts key, NATO requirement and user groups. Cited by the HK MP7 dive. The same brochure is on the Internet Archive as HkMp7a1_text.pdf.
- MP7 A1 — Innovation for the Future: Technical-Data Brochure (Heckler & Koch, 2011)
H&K's technical-data brochure for the MP7A1 (Id.-Nr. 978076/V002.02.11). Cited by the HK MP7 and FN P90 dives for the weapon's published specifications.
- MP7 A1 / MP7 A1-KSK — Instrucciones para el manejo (Heckler & Koch, Spanish, 2006)
H&K's Spanish-language handling instructions for the MP7A1 and MP7A1-KSK (PDF of 3 August 2006), fuller than the English fax copy. The HK MP7 dive uses chapters 2–5, 12, 13, 15 and 16.
- MP7 A1, Cal. 4,6 mm × 30 — Brochure (Heckler & Koch, Spanish, 2007)
H&K's 25-page Spanish-language MP7A1 brochure of 2007. Held with the HK MP7 dive's maker documents.
- MT-055 Tutorial: Chopper Stabilized (Auto-Zero) Precision Op Amps
This six-page tutorial from Analog Devices (MT-055) explains the operating principles of chopper-stabilized (auto-zero) precision op amps, covering the classic chopper architecture and the modern two-amplifier auto-zero topology used in IC implementations. It compares fixed versus pseudorandom chopping frequencies for intermodulation distortion, discusses the patented ping-pong auto-zero/chopper technique used in the AD8628/AD8629/AD8630 family, and provides noise performance data contrasting auto-zero amplifiers against precision bipolar types such as the OP177. Key design guidance notes that choppers should be selected for their ultralow offset and drift rather than their 1/f noise suppression, and that parasitic thermocouple effects in external circuitry must be avoided to realize full performance.
- Multiplier/Divider Module 183 Schematic (Figure V-3)
Single-page schematic (Figure V-3) for the Model 183 Multiplier/Divider sub-circuit, part of the Practical Electronics analog computer construction series. The diagram shows the full circuit topology for an analog multiplier/divider module including op-amps, resistors, diodes, and associated components. Serves as the reference schematic for builders assembling or troubleshooting this specific analog computing element.
- Nachbildung der Saturn V-Rakete auf elektronischen Analogrechnern
Conference proceedings article No. 29 from the 13th Hermann Oberth Society Rockets and Spaceflight Conference (Darmstadt, June 1964). Dipl.-Ing. D.L. Teuber describes how a high-speed GPS analog computer operating in repetitive mode was used to simulate the Saturn V rocket's dynamic behavior with 12 degrees of freedom, accounting for fuel sloshing and bending oscillations. A key contribution is the statistical analysis of atmospheric wind disturbances as stochastic inputs, using both measured wind data on magnetic tape and noise-generator-based synthetic wind profiles, enabling thousands of solutions to be evaluated in minutes to optimize Saturn V control parameters.
- Namco Deadstorm Pirates Special Edition — Operation Manual
A positional (mounted) gun on an LCD.
- Namco Point Blank — Operators Manual (Part No. 90500078)
UK operators manual for the Point Blank light-gun cabinet; the earliest 'blowback' recoil evidence found.
- Namco Time Crisis 3 SD — Operation Manual
Namco's last optical gun, with the lens fire-hazard warning. Downsampled to 150 dpi from a 66 MB scan.
- Namco Time Crisis 4 DX — Operators Manual, Issue 2 (Part No. 90500167)
Deluxe-cabinet manual: the gun's solenoid unit, rubber spacer and +24 V solenoid wiring.
- Namco Time Crisis II — Operation Manual
Operation manual with the blowback test and the ST-0860A2 solenoid in the parts list.
- Namco Time Crisis SD — Operation Manual
Standard-cabinet manual with the gun-solenoid replacement drawing, ST-0860A2 and the silencer rubber.
- Namco Vampire Night DX — Operators Manual (Part No. 90500127)
System 246 deluxe gun cabinet: camera windows and projection. Read for research.
- NanoVNA-F Handheld Vector Network Analyzer — Incomplete Manual (v1.0)
- NanoVNA-F Menu Structure Quick Start Guide (v1.3)
- NanoVNA-F Quick Start Guide (Firmware 1.0.3)
- National Electronics Readout Tubes Catalogue (SB-26F) — Reference
- National Semiconductor AN-440: Driving Vacuum Fluorescent Displays
Application note on VF display drive: the drive-voltage equation, filament bias by Zener on the centre tap, the 'rolling' beat between refresh and filament frequency, and the MM58341/MM58348 drivers.
- National Semiconductor MOS Integrated Circuits (1974)
National Semiconductor's 1974 MOS data book, including its MM57xx calculator chips.
- NAVSHIPS 94971 PP-3494A UG teletype loop supply
NAVSHIPS 94971, PP-3494A/UG teletype loop supply (48 or 120 V DC, magnetic-amplifier regulated)
- Navy EIMB communications service notes on the Model 28 NAVSHIPS 0967-LP-000-0010
Field service notes and modifications. 25 pp. Not read in detail
- NDS Y 7101C 小火器弾薬射撃試験用銃器 — Weapons for Small-Arms Ammunition Firing Tests (Japan MOD standard)
The Ministry of Defense standard for weapons used to test-fire small-arms ammunition (established 30 May 1978, revised 15 April 2015), including bore and chamber gauging. The Type 64 dive cites sections 5.3.1–5.3.1.2 and Tables 1 and A.4.
- Negative Power Functions and Their Graphs
A four-page instructional chapter covering functions of the form f(x) = x^{-n} where n is a natural number. The text addresses domain restrictions, symmetry (odd vs. even functions), horizontal and vertical asymptotes, and the differentiation rule for negative integer exponents, extending the power rule to all integers k. Worked examples include applying the Chain Rule to compositions involving negative power functions such as 1/(x+2) and (sin x)^{-3}.
- Nestler Slide Rules (English export catalogue)
Sixtieth-anniversary English catalogue with the advisory table of the four-digit model range: by then the 25 cm engineers' Rietz was No. 0232 (wood) and No. 0238 (Anagit plastic), with plastic school Rietz No. 0239. Useful for placing a 23 R before the renumbering.
- Nichtlineare Netzwerke NN 800 — Beschreibung und Bedienungsanleitung
Description and operating manual for the Telefunken NN 800 Nonlinear Networks plug-in module (Einschub) designed for use with the RA 800 and RA 800 Hybrid precision analog computers. The 28-page document covers mechanical construction, operating principles, and step-by-step operating instructions for the module's four function types: parabolic multipliers, fixed trigonometric functions (sin and cos at π/2 and π arguments), a logarithmic function (½ log 100x), and variable adjustable functions. Plug-in card (FB card) configurations for each function type are illustrated with detailed diagrams.
- Nickl Schnellfeuer (Mauser Model 712) — US Patent 1,980,874 (1934)
Patent for the select-fire Schnellfeuer mechanism of the Mauser Model 712.
- Nicomachus of Gerasa, Introduction to Arithmetic — translated by Martin Luther D'Ooge, with studies in Greek arithmetic (1926)
The standard English translation of Nicomachus' Introduction to Arithmetic (c. AD 100), the earliest surviving description of the Sieve of Eratosthenes (Book I, ch. 13, pp. 204–206). The translators' footnote observes that the text strikes multiples of every odd number, not only of the primes.
- Nikkan Kogyo Shimbun, 17 July 1967: Character Display at About 25 Volts (with English translation)
A Japanese trade-paper report that Ise Electronics had developed the Digitron, a numeric display tube working at about 25 volts, with an English translation.
- Nintendo Wii Zapper — Operations Manual (C/RVL-A-ZA-USZ)
Trilingual booklet for the Wii Zapper shell: configurations, jacket and strap rules.
- Nintendo Zapper — Instruction Manual (rev. 2)
The NES Zapper's own leaflet: port 2 only, about 6 ft range, TV adjustment, warranty and repair, part no. 2460.
- NIST IR 8547 (initial public draft) — Transition to Post-Quantum Cryptography Standards
NIST's schedule for deprecating RSA and other factoring-based schemes.
- NIST SP 800-57 Part 1 Rev. 5 — Recommendation for Key Management: Part 1, General
NIST's key-length guidance, including RSA modulus sizes and their security strengths.
- Nixie Transistor Clock: Brightness Potentiometer Modification
Adds a 10 k potentiometer in the HV voltage-sense divider (at R336) to adjust the supply from full to half voltage; marked 'older version only' on the KABtronics site.
- Nixie Transistor Clock: Hourly Display Shutdown Modification, Rev 2.1
Adds a 4.7 V zener in series with R287 so each hour's shut-off diode works per hour; applies to PCB version 4 and earlier (built into version 5).
- Nixie Transistor Clock: Version 3 PCB 12-Hour Jumper Fix
Backside jumper for a missing through-hole in the hours decode of version 3 boards; affects 12-hour configuration only.
- Nixie-Transistor Clock Assembly Manual, Document 1.7 for PCB Version 5
87-page assembly manual for the no-IC KABtronics Nixie Transistor Clock (6 x IN-12A): parts list, build order, staged high-voltage bring-up, logic tutorial, circuit description, troubleshooting, and the 23-sheet schematic (Rev 5.0, 2013; scanned images, no text layer).
- No. 1 Step-by-Step Training Manual, Vol II: Sequence Charts and Operational Sketches
Sequence charts and sketches tracing call progress through Bell No.1 SxS.
- Noritake Itron Application Note APN201: Cut-off and Filament Bias
One page of Noritake's VFD application notes: luminance curves against anode and grid voltage, cut-off voltages, and why the filament centre tap carries the bias.
- North American Rockwell: MOS LSI Standard Building-Block Circuits for Calculators (January 1971)
Rockwell's 1971 catalogue of MOS-LSI building-block circuits for calculators, from the period of the four-chip sets in the Sharp QT-8D and EL-8.
- Notes on Caliber .30 Model of 1918 Pistol (the Pedersen Device), Ordnance Department
The Army's confidential instructional notes on the Pedersen Device, cover-named the "Caliber .30 Model of 1918 Pistol": description, installation in the modified M1903 rifle, operation and care. The Pedersen Device dive's primary source for the mechanism.
- Notes on Mechanism of the Chauchat Machine Rifle, Model 1915 — School of Automatic Arms, Camp Kearny
A February 1918 US training pamphlet from the 40th Division's Machine Gun Instruction and Inspection Division describing the Chauchat's parts and cycle. The Chauchat dive uses it with the French instruction for the long-recoil cycle and the American view of the gun.
- NXP UM10204 I²C-bus Specification and User Manual, Rev. 7.0
The I²C specification; rise-time limits and the pull-up resistor formula used for the camera bus.
- OASiS: An Open Architecture Sieve System for Problems in Number Theory (PhD thesis, University of Manitoba)
Thesis on OASiS, the Manitoba open-architecture sieve built in the late 1980s.
- Observations on the Vinous Fermentation
- Ochkov and Khmelyuk, From the Microcalculator to the Personal Computer (1990, in Russian)
Ot mikrokal'kulyatora k personal'nomu komp'yuteru (MEI, 1990, 150,000 copies): a key source on the undocumented behaviour of the B3-34 and MK-61 ('eggogology') (in Russian).
- Office of Naval Intelligence, General Information Series No. XV (1896)
The US Navy's 1896 intelligence annual, which includes a numbered-parts plate and technical description of the Borchardt pistol (the source of the dive's 0.118 in barrel recoil figure).
- Olimex CONNECTOR-GX12-4 Aviation Plug (GX12, 4-pin)
One-page sheet for the GX12 4-pin aviation connector set, including its 5 A rating.
- Olympia CD401A Calculator: Reverse-Engineered Schematic
Schematic of the Olympia CD401A of 1974: TI TMS0206 and TMS0318, HD3281P decoder, TM4312 and TM4352 driver arrays, Futaba 13-MR-01 tube, converter supply with 1.6 V DC filament at -47 V.
- Olympia RAE 4/15-2: Collection Data Sheet
The FAU Erlangen collection record for an Olympia RAE 4/15-2 electronic calculator of 1964, with 15 Nixie tubes.
- Omron B3F Tactile Switch — Datasheet
The picked thumb button; the only published bounce time (5 ms) among the candidates.
- Omron D2F Ultra Subminiature Basic Switch — Datasheet
The picked lever trigger switch (D2F-01F) and its minimum applicable load.
- Omron EE-SX1041 Transmissive Photomicrosensor
Slot photointerrupter used as the shaft index sensor on the chain and gear sieve builds.
- Omron SS Subminiature Basic Switch — Datasheet
SS-01 gold-contact switch, the one in Namco's Time Crisis SD gun.
- Omron V Miniature Basic Switch — Datasheet
V-15-1C25, the PICON-AS trigger switch; 160 mA minimum load.
- On Fermentation
- On the History of the Problem of Separating a Number into Its Prime Factors (Scientific Monthly 7, 227–234)
D. N. Lehmer's history of factoring methods, from the father who built the factor tables.
- ON7DQ — The NanoVNA: From Theory to Practice
- onsemi NSI45090JD Adjustable Constant Current Regulator & LED Driver — Datasheet
Adjustable 90–160 mA CCR in DPAK; the alternative IR-emitter current regulator.
- OP-20-G, "Termination of researches on CCM at Arlington Hall" (Lt A. H. Clifford)
US security evaluation of the CCM (2 pp.) [writer A]
- OP-20-G, "The Period of the CCM"
CCM period analysis (2 pp.) [writer A]
- OP07 Ultralow Offset Voltage Operational Amplifier Data Sheet
Datasheet (Rev. G, October 2011) for the Analog Devices OP07 ultralow offset voltage operational amplifier, covering OP07E (0°C to 70°C) and OP07C (−40°C to +85°C) performance grades. Key specifications include a maximum input offset voltage of 75 µV (OP07E), long-term VOS stability of 1.5 µV/month maximum, input noise voltage of 0.6 µV p-p (0.1 Hz to 10 Hz), open-loop gain of 200 V/mV minimum, and supply voltage range of ±3 V to ±18 V. The document provides full electrical characteristics tables, typical performance curves (gain vs. temperature, noise, CMRR, PSRR), application circuits including thermocouple amplifier, absolute-value circuit, and precision summing amplifier, package outline dimensions for 8-lead PDIP and SOIC_N, and ordering information.
- Open Enigma for Dummies
User guide to the Open Enigma's modes, settings and worked messages (v20140823).
- Open Enigma Mark 4 with Plugboard — Assembly Instructions
Parts list and step-by-step assembly of the three-board Open Enigma with the banana-jack plugboard.
- OpenFIRE Hardware Guide, Version 1.3
The project's own wiring sheets: camera, Wii-sensor conversion, solenoid, rumble, LEDs, OLED and buttons. Fetched 2026-10-18 (PDF created 2026-10-17); supersedes the v1.2 edition the Reference Electronics dive first quoted.
- OpenJVS and OpenJVS IO — Manual (Document Version 1.2)
JVS connector pinout and the OpenJVS IO HAT design.
- Operating Bulletin 32A1: Installing and Operating Instructions for Type 32A1 P-A-X
Installation and operation of a small AE P-A-X.
- Operating Instructions for CCM (SIGDUBN-1)
Army CCM operating instructions, 13 Mar 1945 (15 pp.) [writer A]
- Operating the Hamann Manus Calculator (English translation)
An English translation of the DeTeWe Manus manual by Knut Faegri Jr., with Steven L. Carter, Heinz Schneemann and Christian Hamann.
- Operational Manual for the Heath Educational Analog Computer Model EC-1
The operational manual for the Heathkit EC-1 Educational Analog Computer covers fundamental analog computing theory, circuit description, and step-by-step operating instructions. The EC-1 features nine DC operational amplifiers (6U8 tubes, open-loop gain ~1000, output ±60 V at 3 mA), five coefficient potentiometers, three initial-condition power supplies (0–100 V), and a multivibrator for repetitive operation at 0.1–15 cps. Illustrative problems—falling body, spring-mass system, simultaneous algebraic equations, projectile, and bouncing ball—demonstrate addition, multiplication by a constant, and integration on a machine intended for teaching and demonstration in engineering, physics, and mathematics.
- Operational Requirements for an Infantry Hand Weapon — ORO-T-160 (Hitchman, 1952)
The Operations Research Office's 1952 Project BALANCE memorandum that analysed combat ranges and hit probability and argued for a weapon delivering several projectiles per aim. The Hyper-Burst Mechanisms dive starts its history of salvo and burst fire here.
- Operations manual for M-125 (A 040/1/321, M-125-3MN and M-125-MN), English translation by "JMcC, U.K." (v2.7.1)
Full English text of the 1978 NVA manual: specifications, key packages, daily key tables, key card, message keys, indicator groups, enciphering/deciphering workflow, de-garbling, worked examples (112 pp.; some pages missing in the original copy)
- Optimierung eines Regelkreises mit Tischanalogrechner und Digitalzusatz
A 1968 Telefunken reprint (Sonderdruck) of an article from 'elektronische datenverarbeitung,' pp. 293–297, by H. Kramer. Describes how the Telefunken RAE 360 desktop analog computer, coupled with the DCR 100 digital attachment, is used to optimize a PID control loop by minimizing the quadratic integral criterion ∫e²(t)dt via an automated iterative hill-climbing algorithm. The digital unit systematically varies the three controller parameters (K_P, T_N, T_V), triggers simulation runs on the analog computer, and converges on the optimal parameter set without manual intervention.
- Oral History Interview with D. H. Lehmer (Smithsonian/AFIPS Computer Oral History, 18 April 1973)
Transcript of a 1973 interview in which Lehmer recalls building the chain, gear and electronic sieves.
- Oral History of Bill Mensch (2014)
Mensch on designing the 6800 and 6502 support chips, the 6530 RIOT and the KIM-1, and the Western Design Center.
- Oral History of Chuck Peddle (2014)
Peddle on Motorola, the 6800, MOS Technology, the 6502, the KIM-1 and the Commodore PET.
- Oral History of John Blankenbaker (2007)
Blankenbaker on his career, SEAC, the design of the KENBAK-1 and selling it. CHM X4068.2007.
- Oral History Transcript: General Lemuel C. Shepherd Jr., USMC (1966–1967)
The transcribed memoir of General Lemuel C. Shepherd Jr. from interviews of 1966–67, including his First World War service with the 5th Marines. The Chauchat dive searched the full text and found that the much-repeated "damned Chauchat" quotation attributed to him does not appear in it.
- OSS file — Military Equipment and Supplies for Guerrilla Operations / Production of STEN Submachine Guns and Ammunition in the U.S. (1942)
A 53-page declassified OSS file from September 1942 on supplying guerrilla operations, including the proposal to have STEN guns and their ammunition produced in the United States (with requests of 2,500 guns for Chinese special operations). Wartime carbon copies; the OCR text is rough and should be checked against the page images before quoting.
- Otis King's Patent Calculator — instructions (Models K and L)
The 8-page folded instruction leaflet supplied with the Otis King: outline drawing of holder, cylinder and cursor with top (T) and bottom (B) arrows; scale details for Models K and L (66-in holder scale; K cylinder with two decades meeting at the 'ONE' middle unity; L cylinder with a log number scale plus a 0–1 linear mantissa scale); the three-movement method; multiplication, division, proportion, percentage, constant-factor and sterling examples; closing in / opening out the Model L cylinder; logs, powers and roots on Model L; decimal-point rules. Same Dundonald Road edition as the sheet in my box with serial T3271.
- Otis-King — Conclusions?
Follow-up survey of Otis King serial numbers from members' examples: serial-letter series and estimated production, Types A–E (including the early Type D and the walking-cane Type E), and Otis Carter Formby King's patents and addresses (Coventry, then 51 Holborn Viaduct).
- Oxford Night Caps, Being a Collection of Reciepts for Making Various Beverages Used in the University - 3rd ed
- P-A-X Business Telephone System (brochure) — Automatic Electric (1950)
3 large pages. Switchboards 32A1, 32A21, 32A31, 47A, 47B, 25, 50, 75
- P46 Data Sheet (Heckler & Koch, December 2004)
H&K's four-page P46 data sheet ("Stand: Dezember 2004"). Cited by the HK MP7 dive.
- PABX training advertisement, Types 40, 80, 100 — Automatic Electric (1960)
1 large page
- PACE TR-10 Analog Computer
A 16-page promotional brochure for the EAI PACE TR-10 desk-top analog computer, a fully solid-state, plug-in-component machine consuming under 60 watts and operating from 115 V/60 Hz. The brochure describes the TR-10 system architecture (attenuator, non-linear, and amplifier rows; human-engineered control panel with null meter), lists interchangeable plug-in modules (dual op-amps, integrator networks, multipliers, variable DFGs, log DFGs, comparators, function switches, reference panel, tie-point panels), works two application examples (second-order linear ODE and Van der Pol non-linear ODE), and catalogs accessories including the Accessory Group Type 2.246 for high-speed repetitive operation. Physical specifications are given: 16 in. wide x 22 in. high x 24 in. deep, 50 lb basic / fully expanded weight, power under 50 watts. Bulletin No. 60-309, published by Electronic Associates, Inc., Long Branch, New Jersey.
- PACE TR-20 / TR-48 Desk Top Analog Computers
A six-page color sales brochure from Electronic Associates, Inc. (EAI) promoting the PACE TR-20 and TR-48 desk-top analog computers. The TR-48 features up to 48 amplifiers, the widest usable bandwidth of any desktop computer, high-speed repetitive operation (100 to 5000:1 time-scale change), solid-state readout, removable color-coded patch panels, and low-power compact design operating from 115/230 V at 50/60 Hz. The TR-20 is a portable fully transistorized 15" x 27" unit with up to 20 amplifiers, interchangeable non-linear computing components, variable diode-function generators, and an inclined color-coded patch panel; typical applications listed for both machines span aerospace guidance, nuclear reactor simulation, chemical kinetics, biomedical modeling, and geophysical analysis.
- PACE TR-48 Analog Computer
Marketing brochure (Bulletin No. AC 6222-1-B) for the EAI PACE TR-48 solid-state analog computer, describing its five-step problem-solving workflow, modular removable patch panel, and plug-in computing components including dual amplifiers, integrator networks, coefficient potentiometers, multipliers, variable/log/X² diode function generators, and comparators. The TR-48 is offered in four configurations (TR-48-0 through TR-48-3) scaling from 10 to 48 operational amplifiers; the fully expanded unit draws under 150 watts, weighs 320 lbs, and supports optional High Speed Repetitive Operation with solution times of 20–500 milliseconds.
- PAL-II User Manual V1.0 (2024)
The PAL-2 KIM-1 replica: assembly, jumpers and operation.
- Panasonic JE-850 Instruction Manual
The 16-page manual of the Panasonic JE-850 MOS-LSI desk calculator.
- Partial Differential Equations for Heat Conduction Analysis of Frozen Layer Shifting
Technical Information Series No. 11 from Hitachi demonstrates how the heat-conduction partial differential equation governing the shifting of a frozen soil layer is converted to a set of finite-difference equations and solved on a Hitachi analog-hybrid computer. The document derives boundary conditions for a one-dimensional frozen/unfrozen soil column, scales the equations to machine variables, and presents temperature-transition curves (time and depth as parameters) obtained from the simulation. A full block diagram for the HITAC 505 High-Precision Analog Computer implementation is included, showing 7 integrators, 19 summing amplifiers, 12 sign-changers, 7 potentiometers, 2 dead-zone units, and 15 diodes.
- Parts Model 28 Printer Teletype Bulletin 1149B 1963
Illustrated parts list; type box options
- PBX Systems No. 756A: Equipment Diagram and Index — Western Electric ED-65895-10 (1968)
6 pp
- PEAC: Practical Electronics Analogue Computer
A collected series of articles from Practical Electronics magazine describing the design, construction, and operation of PEAC (Practical Electronics Analogue Computer), a low-cost, general-purpose transistorised analogue computer intended for amateurs and students. The machine is organized into modular units (A through D) covering power supply, operational amplifiers, integrators, a function generator, and a four-quadrant multiplier, with a full PEAC installation costing around £60 circa 1968. The articles cover theory of analogue computing, circuit descriptions, programming techniques, and example problems including differential equations and mechanical system simulation.
- Pearl Harbor Revisited: United States Navy Communications Intelligence 1924–1941 (3rd ed. 2013)
Research Desk 1924, Safford and Meyer, intercept stations, On-the-Roof Gang, fleet exercises, OP-20-G organisation to 1941 (93 pp)
- PEK Analogrechner Stromläufe (38500-Serie)
A set of 10 engineering circuit-diagram sheets (Stromläufe) for the PEK 38500-series analog computer, covering drawing numbers Fs 38501 through Fs 38509. Sheets document the internal circuitry of individual plug-in computing modules including potentiometers, summing amplifiers, integrators, servo multipliers, a diode-network multiplier or function generator, precision rectifiers, a digital-voltmeter interface (TE 340), and the programming-panel wiring matrix. All drawings include component-value annotations, backplane connection tables, and German-language legend blocks.
- Personal Computer World, August 1987: Psion Organiser II Benchtest
Personal Computer World's review of the Psion Organiser II.
- Perspektivische Darstellung von Rechenergebnissen mit Hilfe eines Analogrechners
A short AEG-Telefunken application note (7 pages, document ASD 051 0469) describing how an analog computer can generate perspective (three-dimensional) representations of computed results on an oscilloscope by adding weighted projections of a third variable z to the X and Y deflection channels. The note presents five circuit variants using multipliers and potentiometers to set a fixed or continuously rotating viewing angle, and illustrates the technique with a damped oscillatory differential-equation system whose phase-plane trajectory is displayed as a rotating 3D spiral at multiple viewing angles.
- Philip Dalton: The Lost Navigator
Biography of Philip Dalton, inventor of the E-6B, quoting his letters and his commanding officer's letter.
- Philips Philicorda 22GM751 Service Manual (1967, German)
Philips service manual (German, 22 pp.) for the valve 22GM751 Philicorda: specification and valve list, block-diagram description, tuning procedure, oscillator/neon-divider boards (Units J, K, L), power supply and transistor amplifier schematics.
- Phoebus Corporation and Rayolite Rifle Range Co. v. Ford Amusement Devices — Proceedings Transcript, 1 July 1936
Court transcript for 1 July 1936 in In Equity No. 15,014, the suit over the Rayolite light-ray gallery patents (2,007,082 and 2,007,083). The History of Light Guns dive draws the first light gun's business history from the five days of transcript.
- Phoebus Corporation and Rayolite Rifle Range Co. v. Ford Amusement Devices — Proceedings Transcript, 27 May 1936
Court transcript for 27 May 1936 in In Equity No. 15,014, the suit over the Rayolite light-ray gallery patents (2,007,082 and 2,007,083). The History of Light Guns dive draws the first light gun's business history from the five days of transcript.
- Phoebus Corporation and Rayolite Rifle Range Co. v. Ford Amusement Devices — Proceedings Transcript, 28 May 1936
Court transcript for 28 May 1936 in In Equity No. 15,014, the suit over the Rayolite light-ray gallery patents (2,007,082 and 2,007,083). The History of Light Guns dive draws the first light gun's business history from the five days of transcript.
- Phoebus Corporation and Rayolite Rifle Range Co. v. Ford Amusement Devices — Proceedings Transcript, 29 June 1936
Court transcript for 29 June 1936 in In Equity No. 15,014, the suit over the Rayolite light-ray gallery patents (2,007,082 and 2,007,083). The History of Light Guns dive draws the first light gun's business history from the five days of transcript.
- Phoebus Corporation and Rayolite Rifle Range Co. v. Ford Amusement Devices — Proceedings Transcript, 30 June 1936
Court transcript for 30 June 1936 in In Equity No. 15,014, the suit over the Rayolite light-ray gallery patents (2,007,082 and 2,007,083). The History of Light Guns dive draws the first light gun's business history from the five days of transcript.
- Pickett Teaching Guide for Slide Rule Instruction (Manual 601)
Pickett's teacher's guide for junior- and senior-high classes, in twelve sections: introducing the rule, basic principles (adding lengths with two foot-rules), multiplication and division, approximation, scientific notation, the 'powers-of-ten' rule, A and B, K, CI, logarithms and how the L, C and D scales are made, S/T/ST, and operation in terms of logarithms. Repeatedly directs the teacher to set problems on the 'large demonstrator rule' for the class to read (2 × 3 = 6 on the opening page). The back pages of this printing carry Pickett's catalogue, including the 'Wall Rules' entry: Eye-Saver Yellow, specially treated plywood, adjustable metal end plates, hard-faced plastic cursor, plastic slider inserts, hung from wall, ceiling or blackboard, duplicating both sides of the N3, N4, N500, N902 and N1010 in 4-ft (…WR-4) and 7-ft (…WR-7) lengths; also the PR12/PR13 overhead-projection rules.
- PicoMite Firmware — Advanced Graphics Functions User Manual
- PicoMite MMBasic — Embedded Fonts Guide
- PicoMite MMBasic — Game Input Devices User Manual
- PicoMite MMBasic — GPS & Astronomical Commands Reference
- PicoMite MMBasic — Quick Reference (v2)
- PicoMite MMBasic — Stepper Motor Control Reference
- PicoMite MMBasic — Structures (User-Defined Types) User Manual
- PicoMite MMBasic BITSTREAM Command — User Manual
- PicoMite MMBasic BLIT Command — User Manual
- PicoMite MMBasic DRAW3D — 3D Graphics User Manual
- PicoMite MMBasic FRAME Command — User Manual
- PicoMite MMBasic Interpreter — User Manual (Ver 6.02.01)
- PicoMite MMBasic OPTION GPS — User Manual
- PicoMite MMBasic PLAY SAMPLE Command — User Manual
- PicoMite MMBasic Raycaster (RAY) — User Manual
- PicoMite MMBasic SPRITE — Command and Function Reference Manual
- PicoMite MMBasic TILEMAP Command — User Manual
- Piecewise Continuous Functions
A three-page calculus lecture note covering left and right limits, the formal definition of continuity, and piecewise continuous functions. The text defines left/right limits and vertical asymptotes, distinguishes continuous from discontinuous functions, and introduces left/right continuity with worked examples. Piecewise continuous functions are presented as functions continuous everywhere except at a finite number of points, with the observation that differentiability requires continuity.
- Pistole vz. 08 (něm.) — Czechoslovak Police (SNB) Weapons Text of 1946 (Muzeum Policie ČR transcription)
A Czech Police Museum transcription, in Czech, of the 1946 weapons-instruction text for members of the SNB on the German P08 ("Pistole vz. 08"): principle, main parts and field stripping. The Luger P08 dive translates it for the post-war Czechoslovak police use of the pistol.
- PixArt PAJ7025R2 Multiple Objects Tracking Sensor Module — General Product Datasheet V1.1
The only public PixArt multiple-object-tracking (MOT) camera datasheet found; the camera family used in Wii-style light guns.
- Plessey Telecommunications Catalogue (1971)
132 pp. PAX, PABX, PMBX and rural exchanges; uniselector-based systems
- Pocket Computer Programming Made Easy
Jim Cole's BASIC tutorial for the TRS-80 Pocket Computer and Sharp PC-1211, with material for the PC-2 and PC-1500 (ARCsoft Publishers).
- POEEJ July 1936: The Development of 2000 Type Selector Circuits
British GPO 2000-type Strowger selector design and circuits.
- Polynomial Functions
A three-page mathematics lecture note introducing differentiation rules — the sum rule, difference rule, and constant multiple rule — and applying them to polynomial functions. The document demonstrates how these three rules combine to enable differentiation of any polynomial of the form f(x) = a_n x^n + ... + a_0, with multiple worked examples including higher-degree polynomials up to degree 17. No analog computer content is present; the material is general undergraduate calculus.
- Polynomial-Time Algorithms for Prime Factorization and Discrete Logarithms on a Quantum Computer (arXiv quant-ph/9508027)
Shor's quantum factoring algorithm.
- Position Determination with Loran-C Triplets Using the HP-75C, the Sharp PC-1500 (TRS-80 PC-2) or the TRS-80 Model 100
A Naval Postgraduate School report (NPS55-83-023, September 1983) by Rex H. Shudde with programs for Loran-C navigation fixes on the HP-75C, the Sharp PC-1500 and the TRS-80 Model 100.
- Positive Power Functions
A three-page lecture note covering positive power functions of the form f(x) = x^n for natural numbers n, including graphical properties, symmetry (even and odd functions), and derivative rules. The document derives the power rule df/dx = n·p^(n-1) and introduces the concept of higher derivatives (second, third, and ith derivatives). General mathematics educational content with no specific connection to analog computing hardware.
- Post Slide Rule Instructions — models 1441, 1444, 1447, 1452 (Teledyne Post)
Later (Teledyne era, c.1970s) instruction booklet for Post's Hemmi-made rules including the 1441 four-inch pocket rule, the sibling of the Hemmi 32 that the U.S. Blue Co. pocket rule is. Includes a parts list (indicator glass, complete indicator, snap-on magnifier) useful when sourcing a replacement cursor. 20 pp.
- Practical Directions for the Management of Honeybees
- Practical Distiller
- Practical Electronics, December 1978 — Analogue Computer Part 4 (Conclusion)
The concluding instalment (Part 4) of a four-part constructional series on building and programming a home-constructed analogue computer, published in Practical Electronics, December 1978. The article by P. J. Kronis covers programming techniques including damping systems (impulse, step, sinusoidal and random forcing functions), Lissajous figures, flight simulation of a lunar lander with amplitude and time scaling, and a survey of special circuits such as diode limiters, dead-zone, absolute-value, and flip-flop circuits. The issue also contains a corrected patch-panel diagram (Fig. 3.2) that was misprinted in Part 3.
- Practical Electronics, November 1978 — Analogue Computer Part 3: Wiring, Testing and Programming
Third and final construction installment of the Practical Electronics homebrew analogue computer series, covering mechanical assembly into the case, full wiring schedules for eight edge connectors, offset-null trimming and mode-control testing of all ten computing amplifiers, and programming techniques illustrated by worked examples including ramp/square-law function generation, initial conditions, and the spring-mass oscillator. The issue also contains the Moon Landing game article, which independently uses an analogue computer circuit to simulate rocket descent kinematics.
- Practical Electronics, October 1978 — Analogue Computer Part 2: Construction Details
Part 2 of a multi-part constructional series from Practical Electronics (October 1978) covering the build details of a ten-amplifier analogue computer. The article describes the main PCB layout for ten computing elements (summers and integrators using 741 op-amps), two AD533JD four-quadrant multiplier ICs, relay-based mode control (Compute/Hold/Reset), an overload warning circuit with comparators and LEDs, and a 148-socket colour-coded patch panel. A components list and stage-by-stage construction guidance are included, with wiring and testing deferred to the following issue.
- Practical Electronics, September 1978 — Analogue Computer Part 1: Mathematical Operations and Circuits
First installment of a multi-part constructional series on building an analogue computer, published in Practical Electronics (Vol. 14, No. 13, September 1978). Covers the fundamental theory and circuit building blocks: summing amplifiers, integrators using 741 op-amps, coefficient multipliers (potentiometers), and mode-control logic (Compute / Hold / Reset with Initial Conditions). An overload warning facility is also described. Construction details were deferred to Part 2 (October 1978 issue).
- Practical Information on the Best Method of Brewing from Sugar
- Practical Manual of the E-6B Computer (1944)
Wartime manual for the Dalton E-6B dead reckoning computer: slide-rule and wind-face problems for navigators.
- Practical Treatise on Brewing
- Practical Treatise on Brewing - 1st Ed
- Practisches Lehrbuch der Bayer schen Bierbrauerei
- Präzision mit Geschichte — Test of the Schwaben Arms SAR M41 PSG (Keck, DWJ, January 2023)
A Deutsches Waffen-Journal test (January 2023, pp. 20–25) of the Schwaben Arms SAR M41 PSG, a current German semi-automatic PSG1 pattern. The HK PSG1 dive translates it for the modern reproduction.
- Precision Microdrives 307-103 Vibration Motor — Product Data Sheet
9 mm Pico Vibe ERM, with a reliability (MTTF) analysis. Part of the Motors and Rumble comparison table.
- Precision Microdrives 310-103 Vibration Motor — Product Data Sheet
10 mm Pico Vibe ERM (sampling target spec). Part of the Motors and Rumble comparison table.
- Precision Microdrives 310-118 Vibration Motor — Product Data Sheet
10 mm Pico Vibe ERM (sampling target spec). Part of the Motors and Rumble comparison table.
- Precision Microdrives 312-004 Vibration Motor — Product Data Sheet
12 mm ERM (20 mm type). Part of the Motors and Rumble comparison table.
- Precision Microdrives 312-107 Vibration Motor — Product Data Sheet
12 mm ERM (15 mm type), the fallback; defines normalised amplitude. Part of the Motors and Rumble comparison table.
- Precision Microdrives 324-104 Vibration Motor — Product Data Sheet
24 mm Uni Vibe ERM. Part of the Motors and Rumble comparison table.
- Precision Microdrives 334-401 Vibration Motor — Product Data Sheet
34 mm Uni Vibe ERM, the design-target rumble motor. Part of the Motors and Rumble comparison table.
- Preliminary Apple BASIC Users Manual (October 1976)
Wozniak's Apple BASIC for the Apple-1: statements, functions and the cassette load procedure.
- Preliminary Historical Report on the Solution of the "B" Machine (14 October 1940)
Friedman's report on how the Signal Intelligence Service broke the Japanese PURPLE machine in 1940, written weeks after the break. NSA REF ID A58137.
- Prime Sieves Using Binary Quadratic Forms (Math. Comp. 73, 1023–1030)
The Sieve of Atkin: enumerating primes through binary quadratic forms, asymptotically faster than Eratosthenes.
- Principles of Automatic Telephony Vol II (Mechanical), Part III: Strowger Switch Construction
Construction of the AE Strowger two-motion switch, part by part.
- Principles of Automatic Telephony Vol II (Mechanical), Part IV: Self-Aligning Plunger Lineswitch
Construction of the AE plunger lineswitch.
- Principles of Automatic Telephony: Circuits and Trunking
AE book on Strowger circuits and trunking.
- Private Telephone Systems and Accessories — Automatic Electric, Catalog 4033 (1939)
Complete, 38 pp, OCR. AE P-A-X and P-A-B-X range (32A1 etc.)
- Problem-Solving on the TRS-80 Pocket Computer
A Wiley self-teaching guide to programming the TRS-80 Pocket Computer.
- Probleme der Entwicklung programmgesteuerter Rechengeräte und Integrieranlagen
A 51-page German technical report (Aachen, 1953) compiled from seminar lectures given at the Mathematisches Institut Lehrstuhl C during the 1952 summer and 1952/53 winter semesters, edited by Prof. Dr. Hubert Cremer. The three chapters cover: (1) program-controlled computing machines including stored-program concepts, construction problems, and error correction; (2) development of the Integromat analog integration device including the individual electronic integrator, the step-rate generator (Schritttaktgeber), and error analysis; (3) optimal control problems and their mathematical formulation, together with application of the Integromat to solving such problems.
- Production en série d'un nouveau matériel : Les Calculateurs C.S.F.
A French-language promotional brochure from CSF (Compagnie Générale de TSF) documenting the series production of 100 analog ballistic fire-control calculators for the French Army, delivered in approximately 24 months from 1953–1955. The brochure details the integrated manufacturing chain across CSF group subsidiaries (C.I.C.E., C.A.M.E.C.A., S.T.E.L., S.F.R.) covering special ceramic capacitors, precision servo motors, tube-free calculation blocks, stabilized power supplies, and trailer-mounted cabinet assembly. Quality-control tolerances of under 2 microns for condenser components are highlighted, along with final ballistic acceptance testing and delivery of self-contained trailer units.
- Products and Powers
A three-page calculus lecture note covering two fundamental rules of differentiation. The first section derives and applies the power rule for composite functions, showing how d/dx[(f(x))^n] = n(f(x))^(n-1) * f'(x), with worked examples including trigonometric polynomials. The second section introduces the product rule (Leibniz rule), h'(x) = f'(x)g(x) + f(x)g'(x), demonstrating its necessity and consistency with the power rule through multiple examples including verification that the derivative of a constant is zero.
- Program Manual for Hitachi Analogue Computer — Automatic Programming (Technical Information Series No. 5)
Technical Information Series No. 5 from Hitachi, Ltd. covering automatic programming techniques for the Hitachi analogue computer. Describes logic operation circuits including memory elements, mode control circuits, boundary value analysis, extreme value analysis, and time-sharing computation. Includes worked exercises for each application type, aimed at operators who wish to automate repetitive parameter sweeps and optimization runs on the Hitachi analog-hybrid system.
- Programmez! — Review of the µKENBAK-1 Kit
French magazine review of the µKENBAK-1 kit.
- Programmierung der Steuerbuchsen R, H und P bei den Tischanalogrechern RAT 700, RA 710, RAT 740 und RA 741
Six-page AEG-Telefunken application note describing the programming and use of control sockets R (compute), H (halt), and P (pause) on the RAT 700, RA 710, RAT 740, and RA 741 desktop analog computers. Explains the priority hierarchy among the three socket signals, their interaction with operating modes (single run vs. continuous compute), and illustrates five worked examples with relay-logic timing diagrams covering external halt sequencing, comparator-driven halt control, and pause command behavior.
- Programming an Analog Computer for a Large Class of Trajectories
Technical report TR-1146 from Harry Diamond Laboratories (U.S. Army Materiel Command), dated 20 June 1963. Extends the negative gradient (steepest descent / transpose matrix) method to stable analog computer programming of a broad class of time-varying trajectory problems defined by coupled position and velocity vector equations. Defines an augmented velocity function vector, partitions the problem into reset-mode initialization and compute-mode integration, derives the characteristic matrix differential equation, and establishes stability conditions involving time scaling and gain reduction.
- ProScan Computer-Aided Scanning Software — User Manual (v14.2)
- ProScan Computer-Aided Scanning Software — User Manual (v19.1)
- ProScan Computer-Aided Scanning Software — User Manual (v21.2)
- ProScan Computer-Aided Scanning Software — User Manual (v23.5)
- Proto Labs Aluminum 6061-T651/T6 — CNC Material Data Sheet (2026)
Properties of 6061-T6 for the machined MP7.
- Proto Labs Aluminum 7075-T651/T6 — CNC Material Data Sheet (2026)
Properties of 7075-T6, the stronger alternative.
- Provisional Instruction on the Automatic Rifle, Model 1915 (Chauchat) — War Department Document No. 732
The AEF's English translation of the French Instruction provisoire of February 1916 (revised to 9 June 1917), reprinted by the Army War College in January 1918 as War Department Document No. 732. The Chauchat dive quotes it for the gun's classification as a long-recoil weapon, the mechanism, stoppages and the specified 86 D cartridge.
- Prusament PETG — Technical Data Sheet (v1.1)
16 February 2022 data sheet: density, heat deflection temperature and Charpy impact by print orientation.
- Pukhov, The Real Truth: English Translation with the Lunolet-1 Listing
A seven-page English translation of Pukhov's 1985 story, with the full Lunolet-1 program listing and the game's worked setup (machine-assisted translation).
- PURPLE Revealed: Simulation and Computer-Aided Cryptanalysis of Angooki Taipu B
Reconstruction of the Japanese Type B (PURPLE) cipher machine: sixes and twenties wiring, stepping, a simulator, and the 14-part message of 6–7 December 1941 worked through. Cryptologia 27(1).
- Python Programming for the TI-84 Plus CE Python Graphing Calculator
TI's guide to the TI-Python app on the TI-84 Plus CE Python: the editor and shell, the TI modules (ti_plotlib, ti_system, ti_hub, ti_rover) and sample programs.
- Quadratic Functions
A three-page instructional text covering the definition and properties of quadratic functions of the form f(x) = ax² + bx + c, including roots via the quadratic formula, discriminant analysis, and graphical behavior of parabolas (axis of symmetry, minima, maxima). The document concludes with an introduction to tangent lines and the derivative of a quadratic function, presenting the formula df/dx(p) = 2ap + b with worked examples.
- R.H. Electronics Light Pen — User Manual (BBC Micro)
Rising-edge latch, the 7% error window and one-character resolution.
- R.I.P. 77 — Instructions for M-5 (Orange Diplomatic "B" Machine) (PURPLE), original 15 Jan 1941 with changes to 1 May 1942 (NARA RG 38, Box 40; edited scan by Frode Weierud)
The Navy's PURPLE manual: daily-sequence recovery by the "Probable Word Method" on stereotyped beginnings (FYC + serial number, pp. 2-9 to 2-11), key-sequence development sheets, frequency tally worksheet A5-1 (64-page selection, image-only, no text layer)
- RA 800 Ergänzungsblätter: Multiplizierer, Winkelfunktionen und einstellbare Funktionen
Supplementary programming notes for the Telefunken RA 800 analog computer covering the parabolic multiplier networks (servo multiplier plug-in NN 800), fixed trigonometric function modules (sin x, sin πx, cos x, cos πx), the log₁₀₀ x logarithmic function, and adjustable function modules F(±X). Each section gives step-by-step wiring and programming instructions, including amplifier feedback configuration (330 pF capacitor plug, 20 kΩ normalization) and calibration of summing-point drift.
- Radio City Products (RCP) Model 665 Vacuum-Tube Volt-Ohmmeter / Insulation Tester — Schematic (Sheet 1)
- Radio City Products (RCP) Model 665 Vacuum-Tube Volt-Ohmmeter / Insulation Tester — Schematic (Sheet 2)
- Radio Shack TRS-80 Pocket Computer Solutions to Composite Materials Formulas
A US Air Force Materials Laboratory report (AFWAL-TR-81-4074, August 1981) by Won J. Park of Universal Energy Systems: composite-materials formulas programmed on the TRS-80 Pocket Computer.
- RadioShack PRO-18 Digital Trunking Handheld Scanner — Owner's Manual
RadioShack's owner's manual for the PRO-18 (marketed as "iSCAN Digital"), a GRE-built version of the PSR-800 handheld: programming from the on-board RadioReference library into 101 playlists, P25, Motorola, EDACS and LTR trunking, searching, recording, SAME and weather-priority alerting, and specifications.
- RadioShack PRO-668 Digital Handheld Scanner — Owner's Manual
A short (9-page) owner's manual for the RadioShack PRO-668, a Whistler-built digital handheld related to the WS1080: ZIP-code programming, playlists, searching, recording and playback, SAME weather alerts, V-Scanner backup and the settings menus. Scanned copy; the text layer is OCR and carries errors.
- Raspberry Pi PCN 32 — Products Moving to RP2350 A4 Silicon Stepping
Product change notice: Pico 2 and other RP2350 products move to the A4 stepping, which fixes erratum E9.
- Raspberry Pi Pico — Datasheet
- Raspberry Pi Pico — Product Brief
Six-page brief with the 21 × 51 mm board outline used to size the carrier inside each donor.
- Raspberry Pi Pico 2 — Datasheet
- Raspberry Pi Pico 2 W — Datasheet
CYW43439 pins, VBUS sense on WL_GPIO2 and the antenna keep-out.
- Raspberry Pi Pico-series — Getting Started (C/C++ Development)
- Raspberry Pi Pico-series C/C++ SDK — Documentation
- Raspberry Pi Pico-series Python SDK — Documentation
- Raspberry Pi RP2040 — Datasheet
- Raspberry Pi RP2350 — Datasheet
- Rational Polynomial Functions
A five-page lecture note covering rational polynomial functions and their domains, the technique of polynomial long division for decomposing such functions into a polynomial part and a remainder, and the resulting analysis of horizontal, slant, and vertical asymptotes. Three worked examples illustrate how the polynomial part governs behavior as x approaches positive or negative infinity, while the remainder governs behavior near points outside the domain. The treatment is introductory calculus-course level with no connection to analog computing hardware.
- Raw Thrills Big Buck Hunter Pro — 27" Dedicated Operator's Manual (040-00001-00)
Gun calibration schedule.
- Rechenanlage "Verograph" zur genauen, laufenden Distanzbestimmung — Früher elektrischer Analog-Rechner
A 28-page technical-historical study (December 2018) by André Masson examining the Contraves AG "Verograph" system, an early electrical analog computer developed from ~1936 for continuous real-time aircraft range determination using two theodolites spaced 1–2 km apart and resistance-network computing elements operating at 75 Hz AC. The article reconstructs the sine-rule geometry, the two-stage coordinate transformation that reduces uniform precision errors across the sky, and the Wheatstone-bridge-based resistance-selector technique used in place of amplifier tubes. The companion "Stereomat" device (same technology, post-hoc 3-D shell-burst error computation) is also introduced, and Fritz Fischer's role as Contraves founder and chief inventor is documented.
- Rechenbeispiele fur den RAR Analogrechner — Rechenbuch 1
Chapter 6 of a programming guide for the RAR small analog computer (±50 V machine voltage), presenting worked computing examples covering basic summing and integration operations, diode function generator use, first- and second-order linear differential equations (including spring-mass systems), and implementation of discontinuous functions (comparator, signum, absolute value). Each section provides the circuit configuration, governing equations, and oscillogram results. The document was created in 2010 by Oliver Bach and appears to be a self-contained workbook excerpt (Rechenbuch 1).
- Rechenbeispiele: Einführung in die Analog-Rechentechnik
An 18-page German-language introductory workbook presenting annotated analog computer circuit examples covering summers, integrators, multiplier units (multiplication, division, squaring, square root), trigonometric and discontinuous function generation, and first- and second-order linear differential equations including a spring-mass system. All examples use dimensionless machine units (±1 = ±10 V) and include oscilloscope waveforms to validate the computed results.
- Rechenschieber von Faber-Castell (8th edition)
Bilingual (German/English) collector's catalogue of every known A. W. Faber / Faber-Castell slide rule, with production ranges (2/83 Novo-Duplex 1962–1972; 2/83N 1969–1975), materials (Geroplast polystyrene 1952–1977), and the key to blind date stamps (1958–1977: MYY or MMYY, usually on an end edge of the stock on duplex rules).
- Recommendations for Legion of Merit and Medal for Merit Awards (Friedman to Col. Corderman, 27 Sept 1943; NSA REF ID A41411)
Friedman's credit list for PURPLE (Rowlett, Ferner, Feinstein, Small, Snyder, Prather, Rosen, Dunning, Marston), JMA, J-18/J-19, Floradora, Japanese Army systems (11 pp)
- Reconstructing the Antikythera Mechanism's Central Front Dial Parts — Division and Placement of the Zodiac Dial Ring
Journal of Astronomical History and Heritage 28(1), 257–279.
- Red and Purple: A Story Retold (Cryptologic Quarterly)
NSA's retelling of the breaks of the Japanese RED and PURPLE diplomatic cipher machines.
- Reference Guide for the TI-84 Plus CE Graphing Calculator
Every command and function of the TI-84 Plus CE in the catalogue, with syntax, and the full list of error messages.
- Regla de cálculo de precisión Novo-Biplex No. 2/83N, 62/83N — instrucciones
Spanish-language version of the 2/83N/62/83N instructions, from the export issue sold as 'Novo-Biplex'. Same content as the English manual.
- Relay Magic
AE promotional booklet on relays (image only).
- Remarks and Experiments on the Different Parts of Brewing
- Reparaturanleitung Hamann Automat S
The factory repair manual for the Automat S, in German, 29 pages: the switching-latch drum, adjustments, a fault table and service figures. The drum is the same mechanism as the Manus's, so it is the nearest thing to a Manus repair manual.
- Replaceable Parts List: Digital Voltmeter Model 26.268 and Display Unit Model 554.048 (Appendix 1)
Appendix 1 of the EAI 580/680 TDVM documentation, providing a complete replaceable parts list for the Digital Voltmeter Model 26.268 and Display Unit Model 554.048. Fourteen sub-assemblies are itemized with EAI part numbers and availability category (A: locally available; B: order from EAI), covering the main frame, dual DC amplifier, reference amplifier, miscellaneous and conversion delay networks, summing resistor network, comparator and diode gate, BCD decimal-decoding matrix/counter, power supply regulator, programmer, and readout display module. Dated 8/26/68 and issued by EAI Instrument Division, Long Branch, New Jersey.
- Replica 1 Plus Setup and Users Manual (June 2014)
Assembly, setup and use of the Replica 1 Plus Apple-1 replica (sold today by ReActiveMicro).
- Report of Board on Tests of Revolvers and Automatic Pistols (US Army, 1907)
The US Army board's report on its 1907 trials of .45 revolvers and automatic pistols, printed as an appendix to the Annual Report of the Chief of Ordnance with nine plates. The Luger P08 dive reads the .45 Luger's velocity table from it; the Bergmann 1896/1897 dive cites its test of the .45 Bergmann.
- Report on the Automatic Telephone Situation in the City of Chicago
Engineering report on the Chicago automatic (AE) telephone system.
- Review: List of Prime Numbers from 1 to 10,006,721 (Nature 95, 254)
Contemporary Nature review of D. N. Lehmer's 1914 table of primes up to 10,006,721.
- Ricomac 1216 Calculator: Reverse-Engineered Schematic
Schematic of the Ricomac 1216 of 1974: Hitachi HD3574 and HD3256, HD3233 and TM4352 driver arrays, Futaba DG10W1 tubes with an SP10D5M sign tube.
- RL1200 12-Hour 4-Digit Relay Nixie Clock — Schematic
KiCad schematic (2021-08-10) of the 54/55-relay G2R-2 nixie clock: capacitor-sampled relay registers, XOR-coil incrementers, relay decoder trees, CD4521/CD4017 timebase and MC34063 nixie HV boost.
- RL1200 4-Digit 12-Hour Nixie Clock — Board Datasheet (BOM, Placement, Ports)
Bill of materials, parts placement drawing and port list (2021-08-09). Note: BOM omits R11, R33 and C16, and the drawing shows K46, which the later 54-relay board drops.
- Rolle's Theorem and the Mean Value Theorem (Section 3.7)
Section 3.7 of an open-source calculus text by Dan Sloughter, covering Rolle's Theorem and the Mean Value Theorem with full proofs. The section establishes that a differentiable function on an interval must attain its average rate of change as an instantaneous rate of change at some interior point, then applies this result to determine intervals of increase and decrease and to prove that two antiderivatives of the same function differ by a constant. Worked examples, geometric interpretations, and a problem set of 16 exercises are included.
- Rotary telephone dials: two families
AE vs WE rotary dial families, pulsing and sound.
- Royal Digital V Calculator: Reverse-Engineered Schematic
Schematic of the Royal Digital V pocket calculator of 1972 with an eight-digit fluorescent tube.
- Russian Nixie Tube Data Sheets (compilation)
A compilation of data sheets for Soviet IN-series Nixie tubes, from Dieter Waechter's tube archive.
- Sa vz. 61 Pistol — Návod k použití (Czech Small Arms, Czech edition)
The Czech-language edition of Czech Small Arms' manual for the semi-automatic Sa vz. 61 pistol, named in the Škorpion vz. 61 dive's intake list alongside the English edition it quotes.
- Sa vz. 61 Pistol Instructions Manual (Czech Small Arms, English, 2016)
Czech Small Arms' English manual (29 September 2016) for its semi-automatic Sa vz. 61 pistol in 7.65 mm Br., 9 mm Br., 9 mm Makarov and .22 LR. The Škorpion vz. 61 dive cites it, quoted as published, for the parts it shares with the military gun and for stripping.
- SALVO I Rifle Field Experiment — ORO-T-378 (1959)
The Operations Research Office's report on the SALVO I rifle field experiment run at Fort Benning in June and July 1956, published June 1959. The Hyper-Burst Mechanisms dive cites it for the measured hit rates of salvo and burst fire.
- SALVO II Rifle Field Experiment — ORO-T-397 (1961)
The Operations Research Office's SALVO II report (received 31 October 1960, published May 1961). The Hyper-Burst Mechanisms dive cites it for the second field experiment's results on multiple-projectile and burst weapons.
- SAMCO 1.1 Light Gun Wiring Guide
Original SAMCO carrier wiring for the ItsyBitsy 32u4. GPL-3.0 repository.
- SAMCO 2.0 Light Gun Wiring Guide — ItsyBitsy 32u4 3V, M0 and M4
SAMCO 2.0 wiring for the 3 V ItsyBitsy boards; the ancestor of OpenFIRE's ItsyBitsy layout. GPL-3.0 repository.
- SAMCO 2.0 Light Gun Wiring Guide — ItsyBitsy 32u4 5V
SAMCO 2.0 wiring for the 5 V ItsyBitsy 32u4. GPL-3.0 repository.
- SAMCO Light Gun Wiring Guide — All Boards (discontinued)
Single sheet covering every SAMCO board variant, marked discontinued. GPL-3.0 repository.
- Same Sky (CUI) PJ-002A DC Power Jack — Datasheet (rev 1.05)
Right-angle through-hole barrel jack, 2.0 mm pin, 2.5 A rating.
- Same Sky AMT10 Series Modular Incremental Encoder — Datasheet
Capacitive incremental encoder, the alternative to a magnetic angle sensor on a mounted gun.
- Same Sky PJ-005A Panel-Mount DC Power Jack — Datasheet (rev 1.09)
Panel-mount barrel jack, 2.0 mm pin, 5 A; the gun-side jack pick.
- Same Sky PJ-063AH DC Power Jack, 8 A — Datasheet
Shielded right-angle PCB barrel jack, 2.0 mm pin, 8 A; the alternative jack.
- Samopal ZB 47 — Zbrojovka Brno Manual (1947), Ofseta plus Reprint (1997)
Zbrojovka Brno's 1947 manual for the Holek brothers' ZB 47 submachine gun, in the Ofseta plus reprint of 1997 ("odborný český překlad původního návodu k obsluze včetně vyobrazení"), scanned as two-page spreads: the new gun, groups and parts, description, handling and firing, dismantling and cleaning, technical data. The ZB 47 dive's primary source, translated.
- Sanyo ICC-0081 Logic Circuit Diagram
A 26-page Sanyo service document for the ICC-0081: block diagram, register and sequence charts, key-signal schematic and gate equations for its four LSI chips.
- Schaltungen der Analogrechentechnik
A collection of 95 fully derived and practically tested analog computing circuits by Dipl.-Ing. W. Ammon, published as Band 9 of the supplement series to the journal 'Elektronische Rechenanlagen' (R. Oldenbourg, Munich/Vienna, 1966). The 146-page book covers rational transfer functions, dead-time simulation, division, square roots, trigonometric functions, coordinate transformations, sine/cosine generation, hysteresis curve simulation, pulse generation, samplers, and diode function generators, illustrated with 172 figures. Circuits are derived primarily for EAI TR-10/TR-48 and Telefunken RA 770 but are broadly applicable to any analog computer with standard components.
- Schematic: Educational Computer Model EC-1
Full circuit schematic for the Heathkit EC-1 Educational Analog Computer, labeled as page 38 of the assembly/instruction manual. The diagram covers two vacuum-tube operational amplifiers, a repetitive oscillator, coefficient potentiometers, meter junction circuitry, relay binding posts, and the complete AC power supply with transformer and rectifier stages.
- Schlagkraft — Umarex MP7 Airsoft Models (Lechner, DWJ 3/2015)
A Deutsches Waffen-Journal test (3/2015, pp. 52–55) of Umarex's licensed MP7 airsoft models. The HK MP7 dive cites it for the replicas.
- Schlüsselzusatz SZ 42 — Drawings, Heft I (TICOM T666)
Factory drawings of the SZ42, including the motor wheels (N 46153).
- Schlüsselzusatz SZ 42 — Provisional Description, Vol. 1 (TICOM T663)
German manual for the SZ42 cipher attachment: purpose, mechanical structure, wiring, drive and accessories.
- Schwingungsberechnung eines Zwei-Massen-Systems
A 10-page AEG-Telefunken application note demonstrating analog computer simulation of a coupled two-mass spring-damper system subjected to a step disturbance. The document derives the equations of motion, performs amplitude and time scaling (λ = 10 s⁻¹, 10× time expansion), and presents full circuit schematics with potentiometer settings for three cases: linear (Case a), bilinear damper (Case b), and bilinear damper with dead-band spring nonlinearity (Case c). Oscilloscope result traces for mass deflections Y₁ and Y₂ are provided for all three cases.
- Scientific American, 3 August 1895 — "Improved Repeating Pistol" (Borchardt)
Scientific American vol. 73 no. 5 (3 August 1895), including the illustrated article 'Improved Repeating Pistol' on the Borchardt pistol made by Ludwig Loewe & Co. of Berlin, with ten engravings.
- SD-31141 Step-by-Step Systems No.1/350A Test Circuit for station ringers
Bell SxS office test circuit drawing; example of Bell SD/CD format for SxS.
- SD-65741-01: 756A PBX Line, Line Link and Marker Circuit (issue 38D, 1968)
Schematic drawings of the 756A's crossbar line link frame and marker (104 pp.).
- SD-66507-01: No. 755A Station Circuit (issue 10D)
The 755A's key-station, control-key and emergency-transfer circuits.
- Sega Alien3: The Gun — Owner's Manual (UK)
B 5k linear potentiometers in the gun mount, and the vibrate motor and its brushes.
- Sega Genesis Lightguns — Menacer and Justifier notes (Eke-Eke, 2008)
Emulator author's notes on the Sega Menacer and Konami Justifier, reverse-engineered from game code (untested on hardware, as the author says). The candidate list credited it to Charles MacDonald; the document is signed Eke-Eke, 29/07/2008.
- Sega Ghost Squad — Owner's Manual
Owner's manual for the Ghost Squad cabinet: the solenoid 'gun reaction', burn warning and photos of the gun controller.
- Sega Laser Ghost — Owner's Manual
Three-player gun game: volume (potentiometer) replacement and the motor weight.
- Sega Line of Fire Upright — Temporary Manual
Variable-resistor gear adjustment for the mounted guns and the solenoid circuit protectors.
- Sega NAOMI GD-ROM System — Service Manual 420-6620-01
First printing February 2001: JVS versus 'old JAMMA', connectors CN1–CN5 and the JVS TEST screen.
- Sega Primeval Hunt DX — Service Manual
Lindbergh JVS I/O error codes.
- Sega The House of the Dead 4 — Owner's Manual
The gun sensor unit and gun motor.
- Sega The House of the Dead III, Deluxe Type — Service Manual 420-6742-01UK
The IR gun-sense system: LED boards around the screen and the frequency jumper.
- Sega Virtua Cop — Owner's Manual 4201-6149-05
Gun sensor unit COP-2020 and the I/O option board.
- Sega Virtua Cop 2 — Owner's Manual (UK)
Gun sensor board and the RGB loom it taps.
- Sénat, Rapport n° 35 (1989–1990): Transfer of the GIAT Establishments to a National Company (de Villepin)
The French Senate committee report of October 1989 on the bill that turned GIAT's state arsenals, including the Manufacture d'armes de Saint-Étienne, into a national company. The MAS FR-F2 dive uses it for the industrial history of the FR-F2's maker.
- Series 3440 DATAPLOTTER
Product brochure for the EAI Series 3440 DATAPLOTTER, a fast and accurate automatic digital plotting system capable of point, line, and symbol plotting from magnetic tape, punched tape, punched cards, manual keyboard, or analog signals. The system incorporates a built-in VARIPLOTTER (EAI Model 205) for digital-to-analog conversion and accommodates plots up to 20x20 inches. Specifications include accuracy within 0.001 inches, plotting speeds up to 500 lpm for line plots from magnetic tape and up to 300 ppm for punched cards, and a 13-command control code set for fully automatic operation.
- Servo and Handset Attenuators (EAI 580 Console Manual, Chapter 5)
Chapter 5 of the EAI 580 analog computer console manual, covering the servo and handset attenuator subsystem. A fully expanded 580 provides 70 motor-driven servo potentiometers (5K, ±1.0 mV setting error) addressed and set via a DAC keyboard, plus 10 manually set handset pots. The chapter details theory of operation, circuit descriptions for the 0.6.0677 Servo Amplifier Card and associated cards, maintenance and troubleshooting procedures, replaceable parts lists, and a complete set of schematics for all subsystem cards.
- Servo Resolver Type TJ841 — Minispace: Technical Manual
Technical manual for the Solartron TJ841 Servo Resolver, a Minispace unit combining a servo multiplier with a resolver that provides sine and cosine outputs proportional to shaft angle. Covers installation, technical summary (±1% accuracy, 10–250 Hz AC input, 110 V/240 V mains), operational procedures, servo accuracy factors, and principles of operation including electrical multiplication and sine/cosine function derivation.
- Setting-up Early Computer Programs: D. H. Lehmer's ENIAC Computation (Archive for Mathematical Logic 49, 123–146)
The complete reconstruction of D. H. Lehmer's 1946 ENIAC set-up for computing the exponent of 2 modulo primes — the longer companion to "A Week-End Off".
- Sharing the Burden: Women in Cryptology during World War II
CCH booklet opening with Grotjan's September 1940 PURPLE discovery and Rowlett's 1997 quote "a big step forward"; WAAC/WAVES recruitment, Arlington Hall (25 pp)
- Sharp CE-122 Brochure
Sharp's sales brochure for the CE-122 printer and cassette interface.
- Sharp CE-122 Printer/Cassette Interface Instruction Manual
Sharp's instruction manual for the CE-122 printer and cassette interface for the PC-1211, the original of Radio Shack's 26-3505.
- Sharp Compet 17 Calculator: Reverse-Engineered Schematic
A 17-page schematic of the Sharp Compet 17 of 1968: MSI MOS logic and multiplexed Hitachi CD-81 Nixies.
- Sharp Compet ELSI-814 Instruction Manual
The 50-page multilingual manual of the Sharp ELSI-814 desk calculator.
- Sharp EL-5001 Instruction Manual
The 28-page manual of the Sharp EL-5001 scientific desk calculator: statistics, quadratic equations, integration, complex numbers and vectors.
- Sharp EL-8131 Calculator: Reverse-Engineered Schematic
Schematic of the Sharp EL-8131 ELSI MATE of 1978 with a nine-digit Futaba fluorescent tube.
- Sharp ELSI MATE EL-8131 Instruction Manual
The 24-page manual of the Sharp EL-8131 pocket calculator with a Futaba fluorescent tube.
- Sharp ELSI-804 Calculator: Reverse-Engineered Schematic
Schematic of the Sharp ELSI-804 desk calculator of c. 1973: Hitachi HD3276 and HD3253, Toshiba TD2007 clock at 46.1 kHz, TM4356 driver arrays, nine Futaba DG10Q1 or NEC LD8051 tubes, -44 V and -49 V display rails, filaments in series.
- Sharp Micro Compet QT-8D Instruction Manual
The 20-page instruction book of the QT-8D: keys, the combined += and -= keys, worked examples of every operation, decimal point call-back, overflow, and specifications (78 kHz clock, four ELSI chips).
- Sharp PC-1210 and PC-1211 Flyer (Japanese, first version)
A Japanese Sharp flyer for the PC-1210 and PC-1211 pocket computers.
- Sharp PC-1210 and PC-1211 Flyer (Japanese, second version)
A second version of Sharp's Japanese flyer for the PC-1210 and PC-1211.
- Sharp PC-1211 and CE-121 Service Manual
Sharp's service manual for the PC-1211 pocket computer (Radio Shack's TRS-80 Pocket Computer) and the CE-121 cassette interface: specifications, block diagram, RAM maps, display and power circuits, LSI signal descriptions, disassembly, cassette format, check program, circuit diagrams and parts lists.
- Sharp PC-1211 Applications Manual
Sharp's 314-page book of application programs for the PC-1211: equations, matrices, statistics, coordinates and more.
- Sharp PC-1211 Beginner's Textbook for BASIC
Sharp's 52-page introduction to BASIC programming on the PC-1211.
- Sharp PC-1211 Brochure
Sharp's sales brochure for the PC-1211 pocket computer.
- Sharp PC-1211 Instruction Manual
Sharp's own instruction manual for the PC-1211 pocket computer, 106 pages.
- Sharp PC-1500 Instruction Manual
Sharp's instruction manual for the PC-1500 pocket computer (English).
- Sharp PC-1500 Technical Reference Manual
Sharp's technical reference for the PC-1500: the LH5801 processor, machine code and the system.
- Sharp PC-1500A Instruction Manual
Sharp's instruction manual for the PC-1500A.
- Sharp PC-E500 Service Manual
Sharp's service manual for the PC-E500 pocket computer.
- Sharp PC-G850V(S) User Manual (English translation)
An English translation of the manual for Sharp's PC-G850V and PC-G850VS, the last pocket computers.
- Sharp Pocket Computer Katalog (German)
Sharp's German catalogue of its pocket computers and accessories.
- Simmons, "Dr. Jean Alexander Francoise Le Mat and the New Orleans Affair" — ASAC Bulletin 22 (1970)
Document-based biographical paper on LeMat from New Orleans records: census, medical register, family, addresses, the 1856 patent's ceded share and the 1859 partnership with Beauregard. American Society of Arms Collectors Bulletin 22, pp. 33–41.
- Simple Analogue Computer
A 7-page construction article by H. Webster describing how to build a simple analog computer based on a Wheatstone bridge circuit using calibrated potentiometers. The computer performs multiplication, division, evaluation of powers and roots, and logarithmic scaling. Covers circuit description, printed wiring board construction, calibration procedures, and a components list.
- SIMSTAR – An Attached Multiprocessor for Dynamic System Engineering
A technical paper presented at the 1983 Summer Computer Simulation Conference describing the EAI SIMSTAR attached multiprocessor system for dynamic system simulation. SIMSTAR combines high-speed parallel digital arithmetic processors (delivering up to 200 million Normalized Operations-Per-Second), programmable logic, function generation hardware, and a FORTRAN-based simulation language (STARTRAN) to provide cost-effective large-scale continuous simulation. The system attaches to a host computer and integrates parallel math units, digital-to-analog signal conversion, and vector processing to simulate differential equations at frequencies ranging from 30 Hz (structural dynamics) to over 100 kHz (electronic circuits).
- SIMSTAR — An Attached Multiprocessor for Dynamic System Engineering
StarLight Product Information Bulletin No. 04 (July 1983) describing the EAI SIMSTAR attached multiprocessor for dynamic system engineering. SIMSTAR combines a Parallel Simulation Processor (PSP), a Parallel Math Unit (PMU), and a Digital Arithmetic Processor (DAP) to achieve up to 200 million Normalized Operations Per Second (NOPS), enabling real-time or faster-than-real-time simulation of complex continuous and discrete systems. The system attaches to a host computer and is programmable via FORTRAN or the STARTRAN simulation language, with architecture supporting mixed analog, digital, and hybrid computing methodologies.
- Simulateur de Pile Atomique "DJINN" — Product Brochure
Bilingual (French/English) product brochure from Laboratoires René Derveaux (France) for the 'DJINN' Atomic Pile Simulator, a 30-amplifier analog computer (Type 30 A.S.P.) designed for neutronics, kinetics, and nuclear reactor control studies with 0.5% dynamic accuracy. Also covers associated instruments including a digital gammascope, portable ionization chambers, D.C. electrometric amplifiers (C.E.A. patent), precision laboratory power supplies, and subminiature electronic amplifiers for radiation measurement applications.
- Simulating a Bouncing Ball in a Box
A single-page application note by Bernd Ulmann describing how to simulate a bouncing ball in a box on an analog computer, inspired by an earlier Telefunken paper. Three subcircuits are used: one for y-position with gravity and damping via Z-diodes, one for x-position using comparators for wall reflection, and one generating a high-frequency sine/cosine pair to render a circular ball on an oscilloscope screen. The implementation runs on an RA742 analog computer in repetitive mode.
- Simulation Accelerator
A one-page NASA spinoff article describing EAI Simulation Associates' Advanced Real-Time System (ARTS) simulation accelerator, developed under Goddard Space Flight Center SBIR contracts. The system employs an analog model of computation and a scheduling compiler that maps continuous-system source code directly onto data-flow hardware with fine-grain parallelism, achieving better-than-supercomputer performance. A Space Shuttle main engine benchmark — requiring 40 integrators, several hundred summers and multipliers, 38 dividers, and 32 arbitrary function generators — ran in real time with four processors, more than eight times faster than a supercomputer; five ARTS systems were sold commercially through Halifax Corporation.
- Simulation of a Turbojet Engine on a Standard Electronic Analogue Computer for the Purpose of Control Study
A 1956 thesis by U.S. Navy lieutenants Rockcastle and Yates at the Naval Postgraduate School presenting a simulation of a turbojet engine on a standard electronic analogue computer for control study purposes. Non-linear equations describing the engine's static and transient behavior are derived and linearized for analogue implementation; a typical fuel control is simulated and exercised under both transient and steady-state conditions. Results demonstrate that accurate engine simulation is achievable without special-purpose equipment and that positive fuel-flow limiting can maintain maximum allowable turbine inlet temperature during acceleration.
- Simulation of Full and Part-Load Performance of a Free-Piston Gas Generator by Electronic Analog Methods
Master of Science thesis submitted to the United States Naval Postgraduate School (1960) by Lieutenant Commander Alan F. Barnes. The work uses an electronic analog computer (Boeing Electronic Analog Computer) to simulate the full and part-load performance of a free-piston gas generator (SIGMA GS-34), modeling piston dynamics via Newton's second law with analog circuits representing combustion, compression, bounce-cylinder, and friction forces. Results demonstrate that analog simulation can reproduce free-piston gas generator behavior with reasonable accuracy, validating the method for design and performance prediction of free-piston engine systems.
- Simulation of Steam Pressurizing Tank Transients by Analog Computer
A 1956 master's thesis from the US Naval Postgraduate School presenting analog computer simulation of thermodynamic transients in a nuclear reactor steam pressurizer vessel, using a Boeing Electronic Analog Computer with a Sanborn Recorder. The authors develop theoretical equations from thermodynamic first principles and empirical steam-table relationships, then implement them on the analog computer to generate design data for pressurized water reactor pressurizer sizing at 2000 psia. Results include pressure prediction curves and design guidance for minimizing tank size while accommodating normal and accidental surges.
- Simulation von Schwingungssystemen mit Analogrechnern
A 22-page technical paper by Dr. H. Kramer (Staatliche Ingenieurschule Konstanz), contributed to a VDI-Bildungswerk course (Dusseldorf 1969) on solving control and vibration problems with industrial and self-built analog computers. Part I covers qualitative and quantitative analog simulation of linear spring-damper-mass oscillators, including time and amplitude normalization, maximum-value estimation under initial-condition, step, and periodic forcing, and generation of undamped oscillations. Part II treats nonlinear and continuous systems: the mathematical pendulum (small and large deflections), oscillators with nonlinear damping and bistable restoring forces, two-mass systems, and modal simulation of a jumping beam.
- Simulationssystem DO 910 — Bedienungshandbuch
Operator's manual for the Dornier-System GmbH DO 910 hybrid simulation system, which couples a Commodore CBM 8032 computer (32 KB BASIC) to a 25-slot analog section derived from the DO 80 analog computer, interconnected via an IEC 625 (IEEE 488) interface. The manual covers system architecture, MONITOR software operation, patch-field connections and programming examples for all module types (integrators, summers, multipliers, comparators, limiters, function generators, logic, and dead-time element), and an appendix providing complete BASIC code for IEC read/write transfers to the interface.
- Simulationssystem Dornier 960 — Do 960 Systembeschreibung
A German-language promotional brochure and system description for the Dornier 960 (Do 960) hybrid simulation system, covering its CAMAC-based bus architecture, Intel 8080 microprocessor control, and modular analog computing elements. The Do 960 accommodates up to 16 plug-in modules on the Do 960 Bus, each containing integrators, summers, multipliers, digital potentiometers, function generators, limiters, comparators, and electronic switches. Detailed patch-field diagrams and specifications are provided for each computing element type, along with a description of the MONITOR software, BASIC interpreter, and optional logic extension module.
- Sinclair Scientific Instructions
The instruction booklet for the Sinclair Scientific calculator.
- Sine and Cosine
A 3-page lecture note introducing the sine and cosine functions for a mathematics course. Covers the definition of radians, the extension of sine and cosine beyond acute angles via the unit circle, a table of values for common angles, and the Pythagorean identity sin²θ + cos²θ = 1.
- Singer Friden 1115 Electronic Calculator Service Manual (December 1969)
The service manual for the EC-1115: specifications, key functions, worked calculating methods, the Hitachi HD3100 chips, register operation, the anode charge-pump and cathode control circuits of the 12-tube Nixie display, power supply, troubleshooting and flow charts.
- Singer Friden EC-1113 Service Manual (June 1969)
The 132-page service manual for the Hitachi-built EC-1113, with 108 HD700 PMOS chips and 12 Hitachi Nixies; some pages missing.
- Sketchpad: A Man-Machine Graphical Communication System (UCAM-CL-TR-574)
Sutherland's 1963 MIT thesis, reissued by the Cambridge Computer Laboratory with a new preface. Chapter IV covers the light pen on a random-scan display.
- SkyRC B6neo+ Smart Charger — Instruction Manual (v1.20)
Charger parameter table and warnings.
- Small Arms Identification and Operation Guide: Eurasian Communist Countries — FSTC-CS-07-35-66 (1967)
The US Army Foreign Science and Technology Center's July 1967 identification and operating guide to small arms of the Eurasian communist countries. The Škorpion vz. 61 dive uses its paragraphs 25–30, figures 10–11 and Tables I–II for the US view of the gun; the Chinese Type 63 dive also cites it.
- Small Arms Training, Volume I, Pamphlet No. 21 — The Machine Carbine (1944)
The 1944 War Office training pamphlet that superseded the separate 1942 Thompson and STEN pamphlets, covering both machine carbines in one: mechanism, handling, stripping, firing and stoppages, with appendices.
- Small Arms Training, Volume I, Pamphlet No. 22 — Sten Machine Carbine (1942)
The War Office training pamphlet for the STEN, issued 1942 by command of the Army Council: lessons on the mechanism, loading and unloading, holding and firing, stripping and assembling, with figures of the Mk I and Mk II.
- SMC CJ2 Series Air Cylinder, Standard Type — Catalogue
Allowable kinetic energy, piston speed and operating pressures.
- SMC CJP Series Pin Cylinder — Catalogue
Single- and double-acting pin cylinders.
- SMC V100 Series Direct Operated 3-Port Solenoid Valve — Catalogue
Response time, power, flow (C, b, Cv), pressure range and weight for the blowback valve.
- SNK Beast Busters — Manual
Potentiometer-aimed guns with solenoid recoil, and the calibration service bulletin.
- Solartron Minispace Wiring Diagrams
A single-page hand-drawn wiring diagram for the Solartron Minispace analog computer. The sheet shows detailed interconnections between internal modules, power rails (including a -24V reference visible), patch points, and connectors, with handwritten annotations throughout. This appears to be one sheet from a larger set of wiring diagrams for the Minispace system.
- Solomon Systech SSD1306 128×64 OLED Segment/Common Driver with Controller — Datasheet (Rev 1.1)
Small OLED controller; its 400 kHz I2C limit constrains a shared sensor bus.
- Some Consequences Of Continuity
Section 2.5 of the open textbook 'Difference Equations to Differential Equations' by Dan Sloughter, covering two fundamental consequences of continuity: the Intermediate Value Theorem and the Extreme Value Theorem. The section presents the bisection algorithm as a practical method for approximating roots of continuous functions on closed intervals, with worked numerical examples including root-finding for x^5 + x = 1 and optimization of a rectangular fencing problem. Practice problems reinforce both theorems and their computational applications.
- Some New Factorizations of 2ⁿ ± 1 (Bull. AMS 39, 105–108)
Factorizations found with the photoelectric gear sieve, including the factoring of 2⁹³+1.
- Some Notes on Teletype Corporation Jim Haynes 1993
Some Notes on Teletype Corporation (Jim Haynes's greenkeys posts, compiled by Gil Smith)
- Some Results on Pseudosquares (Math. Comp. 65, 361–372)
Pseudosquare results obtained with the Manitoba electronic sieves.
- Sony MSX Technical Data Book — Hardware/Software Specifications
I/O ports B8H–BBH reserved for the Sanyo light pen. Scan by Ivan Latorre, PDF by Eduardo Robsy (2004).
- Sony SOBAX 2500 Calculator: Reverse-Engineered Schematic
A 27-page schematic of the programmable Sony SOBAX 2500 of 1969-70: the 362 cm longitudinal delay line, the phase-locked master clock, Sony 500-series logic and the multiplexed Hitachi CD-81 Nixie display.
- Sony SOBAX 2500 Calculator: Schematic Appendix
Eleven pages of supporting drawings for the Sony 2500 schematic: timing, register maps and state diagrams.
- Sony SOBAX 2500 Calculator: Theory of Operation
A 52-page theory of operation: the delay line time-multiplexed into 16 channels, the PLL clock locked to the line, the 1-2-4-2 serial arithmetic, programming, the display latch, zero blanking and thousands separators.
- Spec 5482S - Instructions
Spec 5482S — Instructions for Modifying a Model 15 Printer from 60 W.P.M. to 75 or 100 W.P.M.
- Spec S-5321 - Instructions
Spec S-5321 — Instructions for Interchanging 110 V 60 Cycle Synchronous and Governed Motors on Model 15 Printers, Model 14 Reperforators and Model 14 TDs
- Special Conference on M-209 Security — minutes, 12 October 1950
Minutes of a 1950 meeting on the M-209's security and on German cryptanalytic work against M-209 traffic in WWII.
- Special Purpose Individual Weapon, Phase I Report (Harrington & Richardson, 1963)
Harrington & Richardson's Phase I report of 17 May 1963 on its Special Purpose Individual Weapon design. The Hyper-Burst Mechanisms dive cites it for the H&R SPIW and its burst mechanism.
- Specifications for General Purpose Desk-Top Analog Computer (TR-10)
A formal procurement/design specification document (document number GPAC-TR-10 PS 6305) issued by Electronic Associates, Inc. for the TR-10 general-purpose desk-top analog computer. It defines detailed performance and construction requirements for all computing components: up to 20 uncommitted operational amplifiers (+-20 uV offset, 50 uV/s drift limit, 200 kHz bandwidth), up to 24 ten-turn potentiometers (0.025% resolution), up to 9 quarter-square multipliers (+-0.4% static error), X2 diode function generators, comparator, function switches, reference supplies, power supply, and a full patching element suite including a high-speed repetitive operation system cycling up to 33 solutions per second. The complete expanded system is constrained to no more than 100 lb and 16 in W x 23 in H x 16 in D.
- Specifications for Transistorized General-Purpose Analog Computer
This 11-page EAI bulletin (No. PS62008-1) is a formal procurement specification for a transistorized general-purpose analog computer intended for desktop use. It covers detailed technical requirements for all major subsystems including up to 48 operational amplifiers, 40 integrator channels, 60 potentiometers, quarter-square multipliers, variable diode function generators, X2 and log-X diode function generators, comparators, function switches, pre-patch panel, reference supply, repetitive operation capability, and patching kits. Key accuracy and performance requirements are specified throughout, such as 0.01% amplifier accuracy, 350 kHz bandwidth, 20 ms to 500 ms solution time range, and plus-or-minus 10 volt reference supplies at 250 milliamperes.
- SPIW Modes of Fire — BRL Memorandum Report No. 1864 (1968)
A Ballistic Research Laboratories report of February 1968 (declassified) comparing the SPIW's modes of fire. The Hyper-Burst Mechanisms dive cites it for the measured value of controlled bursts.
- Sporty's E6B Electronic Flight Computer Manual (Version 05A, 2005)
Manual for Sporty's original electronic E6B (20 aviation functions, 14 conversions, timer and three clocks): every function with worked examples, conversions, care and the FAA-test note.
- Sporty's E6B Electronic Flight Computer Manual (Version 12A, 2012)
Manual for the redesigned Sporty's E6B of 2012 (24 functions, 20 conversions, backlight).
- Sporty's E6B Electronic Flight Computer Manual (Version 13.16A, 2016)
Manual for the current Sporty's E6B, including climb, descent, cloud base and range functions.
- Sporty's Palm E6B Software Manual (Version 03A, 2003)
Instructions for Sporty's E6B software for Palm OS handhelds.
- ST LSM6DSO 6-Axis IMU — Datasheet (DS12140)
Alternative 6-axis IMU compared in the dive.
- ST LSM6DSOX 6-Axis IMU with Machine Learning Core — Datasheet (DS12814)
The bench-trial IMU (Adafruit 4438 breakout).
- ST STUSB4500 Standalone USB PD Sink Controller — Datasheet (DS12499)
The proposed 20 V sink (UP-4).
- ST VL53L1X Long-Distance Time-of-Flight Ranging Sensor — Datasheet (DS12385 Rev 8)
Time-of-flight ranging limits, considered and rejected for aiming.
- ST-6 RTTY Demodulator Instruction Manual HAL Communications Corp Urbana IL 1974
ST-6 RTTY Demodulator Instruction Manual
- Stability Research on Parachutes Using Digital and Analog Computers
NASA technical translation (TT F-10,391) of a 1963 German conference paper by R. Ludwig, presented at the International Symposium on Analog and Digital Techniques Applied to Aeronautics in Liege, Belgium. The paper investigates the dynamic stability of parachutes using nonlinear equations of motion solved on both digital computers (IBM 650, Siemens 2002, using Runge-Kutta) and an analog computer, covering approximately 80 computed cases. It demonstrates that linearization is fundamentally inadequate for describing parachute oscillation dynamics and that analog and digital computation together are essential for this class of nonlinear flight mechanics problems.
- Standard Data Processing Instruments
A product brochure from EAI (Electronic Associates, Inc., Long Branch, New Jersey) presenting the firm's family of standard data processing instruments for use with analog computers. Covered products include the 1100E VARIPLOTTER (11x17-inch X-Y analog plotter with plug-in network capability and a range of accessories including function generators, time-base generator, keyboard dataplotter, and symbol printer), the 3100 DATAPLOTTER System (11x17-inch digital plotter accepting punched cards, paper tape, or keyboard input, with transistorized conversion circuits), the Series 5000 Transistorized Digital Voltmeter (full-time 1000-megohm input impedance, 0.01% +/- 1 digit accuracy, 200 readings per second), an AC-DC converter, and a high-speed printer for digital voltmeter output.
- Starlight: The Ultimate Simulation Computer
Four-page color sales brochure for the EAI Starlight, described as a fast real-time simulation computer using a VME-bus multiprocessor architecture with Arithmetic Computing Modules (ACMs), Data Memory Modules (DMMs), and an Analog Interface Module (AIM) providing 16 ADCs and 16 DACs. The system is programmed in CSSL, FORTRAN, C, or Ada via an Integrated Sequential Processor that compiles and maps simulation models onto the parallel ACMs at run time. A benchmark chart compares Starlight favorably to Motorola, Encore, Intel, and Cray systems in frames-per-second for dynamic simulation.
- Statistical Methods in Cryptanalysis, Revised Edition (War Department, OCSigO Technical Paper; NSA REF ID A58459)
The SIS statistics textbook: defines the phi test (p. 38), cross-product sum/chi test (p. 52 ff.), kappa-r = 0.0385 and kappa-p = 0.066 (pp. 81-82); lists E(phi) for Japanese romaji 0.0819 N(N-1) (206-page scan incl. file cover; declassified 2013)
- STC Uniselectors Types 4150 and 4160 (catalogue data)
Data page for the STC 4150/4160 25-point uniselectors — one of the stepping-switch types proposed for the PURPLE replica build.
- STEN Mk II — Complete Machine Plans (community drawing set)
A widely circulated 24-page anonymous dimensioned drawing set for the Mk II: parts list, then per-part drawings of the receiver, bolt, barrel, trigger mechanism and furniture. Not an official MoS drawing set; verify any critical dimension against the official documents before cutting metal.
- STEN Mk II Compact — Receiver Template (one-sheet)
A single-sheet, print-to-scale receiver layout template for a shortened Mk II. Hobbyist drawing, not official.
- STEN Mk III — Receiver Template (one-sheet)
A two-half, print-on-legal-paper layout template for the Mk III receiver tube with hole positions and overall length (18-1/16 in), plus a note on lengthening for a bolt extension. Hobbyist drawing, not official.
- STEN Mk V — Receiver Template (one-sheet)
A single-sheet, print-to-scale layout template for the Mk V receiver. Hobbyist drawing, not official.
- Step-by-Step Dial System, Pamphlet No. 37
WE installer's introduction to the step-by-step dial system.
- Stockly Electronics KENBAK-1 Reproduction — Parts Placement Guide (2007)
Parts list and placement guide (IC1–IC132, R1–R47, C1–C22, D1–D9, Q1–Q8) for the KENBAK-1 reproduction board. Also published in Artem Kalinchuk's kenbak_1 GitHub repository.
- Stockly Electronics KENBAK-1 Reproduction Kit — Construction Manual (2007)
Construction manual for the 2007 KENBAK-1 Series 2 reproduction kit: packing lists, power supply, case and front-panel wiring, memory carriers, heat sinks. Also published in Artem Kalinchuk's kenbak_1 GitHub repository.
- Stored Program Concept for Analog Computers
This final report, prepared by EAI Applications Engineer George Hannauer for NASA's George C. Marshall Space Flight Center (EAI Project #320009, NASA Order #NAS8-21228), investigates the feasibility of implementing a stored-program concept for analog computers using electronic switching matrices. The report develops mathematical theory for multi-stage crossbar switching networks -- analyzing three-stage matrices with and without fanout, modular analog configuration design, and switch-assignment algorithms -- then demonstrates the concept against NASA simulation problems including Voyager first-stage ascent and Saturn IV stage control. Software routines for switch assignment, matrix terminal assignment, interconnection, and component assignment are also described.
- Stretches and Shifts
A three-page lecture note covering the transformation of functions by vertical and horizontal stretching (scaling) and vertical and horizontal shifting. The document defines each transformation algebraically, illustrates the effects on sine and polynomial examples, and derives the corresponding differentiation rules (constant multiple rule for vertical stretches, chain-rule precursor for horizontal stretches, sum rule for vertical shifts, and substitution rule for horizontal shifts).
- Strowger selector operation diagrams — Sam Hallas repository (GPO-style teaching diagrams)
45 pp. Step-by-step pictures of a final selector and of a uniselector with a homing arc
- Strowger switch parts catalogue
Late supplier catalogue of Strowger switch spare parts with catalogue and manufacturer numbers.
- Study of Electrical Analogue for Electrodialysis
Office of Saline Water Research and Development Progress Report No. 238 (February 1967), prepared by the Astropower Laboratory of Douglas Aircraft Company. Develops a mathematical electrical-network analogue model of the electrodialysis desalination process, decomposing each stage into resistive sub-elements (concentration polarization, ohmic polarization, membrane resistance, electrode polarization, and parasitic duct losses). Applies the model to operating plants at Webster, South Dakota and Buckeye, Arizona, achieving agreement within 94% of measured stack resistance, and projects 15-45% resistance reductions through improved hydrodynamics and advanced membranes.
- Subscribers' Uniselector Circuits (P.O. Telecommunications Educational Pamphlet, Telephones 3/2)
Post Office training pamphlet on uniselector operation and circuits — background for the PURPLE replica's stepping switches.
- Super Scope 6 — Instruction Booklet (Super NES, US)
Game booklet that documents the Super Scope: buttons, POWER/TURBO switch, ADJUST AIM.
- Supplyframe 4-Bit Processor Badge — Hardware Reference
- Supplyframe 4-Bit Processor Badge — Instruction Set
- Supplyframe 4-Bit Processor Badge — Instruction Set in Direct Mode
- Supplyframe 4-Bit Processor Badge — Special Function Registers
- Supplyframe 4-Bit Processor Badge — User Manual
- Swiss Federal Drawings: Ordonnanz zur Pistole 1900 ("Selbstlade-Pistole System Borchardt-Luger")
Seventeen hand-drawn dimensioned sheets of the Swiss Ordonnanz pistol of 1900, headed "Selbstlade-Pistole System Borchardt-Luger", from the Swiss Federal Archives. The Luger P08 dive uses them with the 1900/06 set for the original pattern's dimensions.
- Swiss Federal Drawings: Pistole 1900/1906 ("Selbstlade-Pistole Mod. 1904"), Bundesarchiv Bern Archiv-Nr. 18176
Nineteen hand-drawn dimensioned sheets of the Swiss service Parabellum, headed "Selbstlade-Pistole Mod. 1904" and stamped by the Swiss Federal Archives (Bestand 27, Archiv-Nr. 18176): barrel, frame, magazine and the 7.65 mm cartridge. The Luger P08 dive reads the barrel's 20 tpi Whitworth-form thread, the 250 mm twist and the frame-hardening note from them, and treats the set as the starting point for a from-scratch build.
- SXS Parts Identification Master Drawings (MD)
Exploded master drawings with part numbers for Strowger switch and relay components; essential for repair and ordering parts.
- Synertek SY1402A/1403A/1404A 1024-Bit Dynamic Shift Registers
Second-source datasheet for the 1404A-type MOS shift registers used as the KENBAK-1's memory.
- System Response Analysis with the Analog Memory and Logic System
This EAI application note (Bulletin No. ALHC 64024) describes techniques for analyzing system response characteristics using a general-purpose analog computer equipped with EAI's Analog Memory and Logic System. The document covers three operating modes—real-time simulation, compressed time-scale, and high-speed operation—along with a stroboscopic plotting technique using analog memory units for recording high-speed repetitive solutions and a probability distribution analysis technique using Gaussian noise input.
- Systemanalyse und Reglerentwurf am Beispiel einer elektromagnetischen Aufhängung
A 74-page German Studienarbeit (student research thesis) from the Institut für Mess- und Regelungstechnik, Universität Karlsruhe, submitted in 1980 under Prof. Dr.-Ing. F. Mesch. The work performs a system analysis and PID controller design for an electromagnetic (magnetic) suspension — an inherently unstable, nonlinear plant — and demonstrates how the linearized closed-loop system is simulated on an analog computer. Topics include derivation and linearization of the equations of motion, measurement of the force-distance characteristic and optical sensor curve, root-locus controller synthesis, cascade current-loop design, normalization for the analog computer, and a revised laboratory experiment guide ('Analogrechner II').
- Taito Gunbuster — Manual (partial)
Partial manual: the motor and solenoid outputs.
- Taito Operation Thunderbolt — Operating Manual
Gun sight adjustment procedure and the solenoid assembly part numbers.
- Taito Operation Wolf — Cabinet Service Instructions
Cabinet service sheet: RF filter capacitors on the gun lines, and the interlock.
- Taito Operation Wolf — Operating Manual
Gun wiring that shows the gun is optical, the recoil crank, and gun replacement.
- Taito Space Gun — Service Manual (Electrocoin, Part No. 64082)
UK distributor's manual: the potentiometer-and-gear gun mount and the slide solenoid with its diode.
- Tandy Model PC-4 Pocket Computer Programming Guide
The programming guide for the Tandy PC-4, Radio Shack's version of the Casio PB-100.
- Tangent, Cotangent, Secant, and Cosecant
A four-page calculus lecture note deriving the quotient rule and applying it to define and differentiate the four remaining trigonometric functions: tangent, cotangent, secant, and cosecant. Each function's domain, range, period, symmetry, and vertical asymptotes are detailed, and worked examples demonstrate use of the quotient rule and chain rule to differentiate composite trigonometric expressions.
- TDK InvenSense ICM-42688-P High Precision 6-Axis MEMS MotionTracking Device — Datasheet (DS-000347 rev 1.6)
The proposed carrier IMU for inertial aiming assist.
- TEAL IME 41 Calculator: Reverse-Engineered Schematic
Nineteen-page schematic of the IME 41 desk calculator of 1970, built on MSI MOS logic with individual fluorescent tubes.
- TEAL Royal Digital I Calculator: Reverse-Engineered Schematic
Eighteen-page schematic of the Royal Digital I desk calculator of 1971: 29 NEC and Mitsubishi MOS chips on -24 V, ten Ise DG-12C tubes with filaments in series, grid blanking transistor.
- Technical Bulletin 322: P-A-X/PABX Switchboard Type 50
Type 50 PAX/PABX attendant switchboard.
- Technical Bulletin 405: Test Turret Type 21
AE Type 21 test turret: description and circuits of the exchange test desk used to test lines and switches.
- Technical Bulletin 500-407: Leich Type 40 and Type 80 PABX
Small Leich/AE PABX systems.
- Technical Bulletin 565: General Maintenance of P-A-X's
Routine maintenance of small AE private exchanges.
- Technical Bulletin 961-473: Rotary Stepping Switches
Rotary stepping switch types, adjustment and application.
- Technical Bulletin 961-537: Relays Class B and Class C (Type 57-A and 58-A)
AE Class B relay description and adjustment.
- Technical Description of the Automatic Rifle HK G3, Cal. 7.62 mm NATO (English reprint)
An English-language technical description, operating and maintenance text for the G3, printed by a US publisher with H&K's permission (it states it is not an official manual). The HK PSG1 dive uses it for the G3 receiver, barrel and technical data the PSG1 shares.
- Technical Information Series No. 3: Double Integral (Calculation of Volume of Cone)
This application note demonstrates the use of a Hitachi analog-hybrid computer to evaluate a double integral for calculating the volume of a cone using multiple time axes. The computation slices the cone into N thin cylindrical sections (N=250 for the calculation, N=25 for reference), summing the cross-sectional areas iteratively; results are displayed via pen recorder and pattern display on oscilloscope showing the three-dimensional cone surface. Computing elements required include dual DC amplifiers (DA-151/DA-151A), dual integrators (IN-151/IN-153), potentiometer panels (PT-251/PT-151), voltage comparators (CP-151/CP-152/CP-153), and a square function generator (FG-154A).
- Technical Manual 28 ASR Teletypewriter Sets Vol 1 NAVSHIPS 0967-173-6010 1967
ASR description (573-101-100TC: punches, four TD designs, K/K-T/T modes), installation (573-101-200TC), operating instructions, cross-reference, wiring
- Technical Manual 28 ASR Teletypewriter Sets Vol 2 NAVSHIPS 0967-173-6020 1967
Adjustments, lubrication and disassembly of every ASR unit (573-115/-117/-118/-121/-127/-133/-134/-139, 570-220)
- Technical Manual 28 KSR and RO Teletypewriter Sets Vol 1 NAVSHIPS 0967-173-7010 1967
BSPs 573-100-000/-100/-200/-500/-702, 573-115-100/-700 (Iss 7)/-701 (Iss 3)/-702, 573-116-100/-700/-701/-702, 573-133-xxx, 573-134-xxx, 570-220-100/-700/-701, 570-301-705 (paper winder). Description, installation (gear sets), adjustments, lubrication, wiring. 597 pp
- Technical Manual 28 Transmitter Distributors Teletype Bulletin 252B
LAXD/LCXD TDs. (Hertzmail index titles 252B "Adjustments and Lubrication, Model 28 Transmitter-Distributor LAXD"; the cover reads as given here.) 89 pp
- Technical Manual Motor Units Teletype Bulletin 295B 1970
28 motor units incl. starting capacitor part numbers
- Technical Manual Operation and Maintenance Instructions with Parts List Transmitter Distributor NAVELEX 0967-LP-615-3010 1978
Navy TD sets (TT-187 family). 410 pp
- Technische Information Nr. 2209: Transistor-Rechenverstärker TRV-1
GTE Technische Elektronik technical information bulletin (Nr. 2209) covering the TRV-1 transistor computing amplifier, a chopper-stabilized DC operational amplifier designed for precision analog computing and measurement. The TRV-1 achieves 115 dB DC gain in the main amplifier, long-term drift ≤20 μV and temperature drift ≤1 μV/°C, implemented on a 155×105 mm printed circuit card for rack (magazine) mounting. Note: pages 1–18 of this 20-page scan are rendered unreadable by severe horizontal scan artifacts; content is derived from the two legible pages (cover and data sheet).
- Tekhnika — Molodezhi, 1985 No. 6, with M. Pukhov's 'The Real Truth' and Lunolet-1 (in Russian)
The full 68-page issue of Tekhnika — Molodezhi that printed Mikhail Pukhov's story Istinnaya pravda with the Lunolet-1 lunar-landing program for the B3-34, and launched the Electronic Games Club (in Russian).
- Telecommunications Switching Principles
Modern switching theory text covering step-by-step, crossbar and stored program control.
- Telefunken Analog and Hybrid Computers
A 57-page illustrated presentation by Bernd Ulmann (April 2006) tracing the complete history of Telefunken analog and hybrid computers from the 1955 tube-based prototype through the late-1970s RA770. Covers computing elements, circuit design choices (drift compensation, parabola multipliers), and successive production machines including the RA463, RAT700, RA770, RA775, RA800H, and the HKW900 hybrid coupler unit. Intended as a historical survey and preservation appeal, with photographs of surviving hardware and references to primary Telefunken documentation.
- Telefunken ERV 801 — Elektronik, Rechenkomponenten: Schaltungszeichnungen (Prinzip und Belegungsübersicht)
Two-sheet engineering drawing set for the Telefunken ERV 801 analog computer. Sheet 1 (drawing SS-2005-650) is a principle-level schematic of the electronic computing components, showing operational amplifier stages, integrators, summers, and multiplier blocks with their interconnections. Sheet 2 is a Belegungsübersicht (patch/assignment overview table) mapping computing amplifiers, coefficient potentiometers, and PM3-type multipliers to their physical panel positions and signal routing designations.
- Telefunken RA 463/462 – Mechanik Zeichnungen (Mechanical Drawings)
A set of 13 mechanical front-panel layout drawings (scale 1:1 and 1:25) for the Telefunken RA 463/462 analog computer system, bearing Telefunken drawing numbers AH/MS 0.361 through AH/MS 0.373. Modules depicted include two computing amplifier variants (Rechenverstärker I and II), a multiplier, two function generator types, two potentiometer arrays, a timer, an oscilloscope display panel, two power supplies (±100V and +200V), a patch/switching panel, and a mains voltage regulator. The drawings show connector positions, meter placements, potentiometer arrangements, and control knob layouts at precise scale.
- Telefunken RA770 Operator's Manual — Chapter 2: Operation and Control (Section 3)
Section 3 of the Telefunken RA770 analog computer operator's manual, covering operation and control. Topics include decade selection, operating elements, timer configuration, digital control elements (push-buttons, analog patch panel, digital adapter unit, electronic resolvers, non-linear networks), and balancing and testing procedures. The section covers master and slave control panel configurations, the Digital Adapter Unit (DOU), and supply voltage testing.
- Telefunken Zeitung — Jahrgang 39, Heft 1 (1966)
The Telefunken Zeitung, Year 39, Issue 1 (February 1966), is Telefunken AG's in-house technical journal containing multiple articles on analog and hybrid computing technology. The issue covers the state and development of analog and hybrid computers (by Meyer-Brötz, Klug, Grau, and Haußmann), applications of hybrid computing techniques to analog computing elements, and detailed descriptions of the Telefunken RA 770 and RA1 770 analog computers, along with articles on computing amplifiers, multiplexed operation with semiconductor elements, and error analysis in computation.
- Telephone Apparatus and Supplies for Small and Rural Companies — Automatic Electric, Catalog 4075 (May 38) (1938)
Complete, 85 pp. Title candidate for the photo, but it is **not** the photographed book (no Strowger switch section and no p. 162)
- Telephone Communication Systems (1970), Vol 1 Ch. 4: Step-by-Step
Textbook chapter explaining step-by-step systems.
- Telephone Communications Systems, Vol. 2 (Western Electric training text)
Western Electric training text on central-office switching, with crossbar select and hold magnet operation.
- Telephone Reading Course on Step-by-Step Dial System, Section 1
General description of the SxS dial system for craftsmen.
- Telephone Reading Course on Step-by-Step Dial System, Section 2 (mechanical adjustments)
Mechanical adjustments of SxS central office equipment.
- Telephone Switching Equipment Repairman (Electromechanical), CDC 36251, Vols. 1–5
USAF correspondence course on Strowger step-by-step equipment: relays and the two-motion switch, AE-style line finders and distributors, selectors and connectors relay by relay, power, ringing, maintenance, and the Type 26A switch tester (Vol. 3, ch. 6).
- Telephony, Including Automatic Switching
Textbook covering manual and automatic switching.
- Telephony: A Comprehensive and Detailed Exposition
Large reference including automatic systems.
- Teletype 574-100-201TC 32 and 33 Teletypewriter Sets - Installation Issue 3 Jul 1964
Teletype 574-100-201TC, *32 and 33 Teletypewriter Sets — Installation*, Issue 3, Jul 1964
- Teletype 574-123-101TC 32 and 33 Call Control Unit - Principles of Operation
Teletype 574-123-101TC, *32 & 33 Call Control Unit — Principles of Operation* (selector magnet driver: 0.500 A from a 20 mA or 60 mA line)
- Teletype 574-125-100TC 32 and 33 Tape Punch - Principles of Operation
Teletype 574-125-100TC, *32 and 33 Tape Punch — Principles of Operation*
- Teletype BSP 570-224-100 TP177010 Selector Magnet Driver - Description and Principles of Operat 1965
Teletype / BSP 570-224-100, *TP177010 Selector Magnet Driver — Description and Principles of Operation*, Issue 1, Feb 1965
- Teletype Bulletin 273B Vol 1 Technical Manual 32 and 33 Teleprinter Sets Nov 1964
Teletype Bulletin 273B Vol 1, *Technical Manual, 32 and 33 Teleprinter Sets*, Nov 1964 (182 pp; includes 574-100-102 technical data: 0.020/0.060 A line current, 8-level 11-unit code, tape 11/16 in and 1 in, 10 rows/in, feed hole 0.0465 in)
- TELETYPE equipment
Model 28 family sales catalogue
- Teletype Equipment List - General Description Sheets sales description binder 1948
Teletype Equipment List — General Description Sheets (binder; individual sheets 1946–1954)
- Teletype Instruction Manual No 5 - Teletype Model 19 Manual 5MA 1942
Teletype Instruction Manual No. 5 — Teletype Model 19 (contents, set photos, Spec S-5288 Lubrication Supplies)
- Teletype Model 28 Prototype Info — 1953
Early/prototype 28 apparatus. 71 pp. Not read in detail for this dive
- Teletypewriter Apparatus - General Requirements - Lubrication Section 570-004-701TC 1976
Teletypewriter Apparatus — General Requirements — Lubrication
- Teletypewriter Maintenance Tools Teletype Section 570-005-800TC Iss 6 1977
Spring scales, gauges, wrenches, handwheel degree disc, M28/M35 typing-unit service rest kit. 23 pp. **Second tag:** Restoring-a-Teletype
- Teletypewriter Service Manual Models 14 15 19 28 35 33 BSP 570-001-901MS Iss C 1967
Critical adjustment charts and check lists; receiving orientation tests (80-point check test). 102 pp. **Second tag:** Teletype-Model-15, Restoring-a-Teletype
- Terasic DE10-Nano User Manual (rev. E hardware, v2.6)
The MiSTer base board: HPS/ARM and the GPIO used by the I/O board's user port.
- Terminator Salvation 42" Deluxe — Setup and Operations Manual (rev. 7.30.12)
Gun camera and IR sensor tests.
- Texas Instruments BA II PLUS Guidebook
TI's guidebook for the BA II Plus financial calculator, the 12C's rival in the CFA exams.
- Texas Instruments SN74HC165 parallel-load shift register
- Texas Instruments SN74HC595 shift register with output latches
- Texas Instruments TI-1025 Calculator: Reverse-Engineered Schematic
Schematic of the TI-1025 of 1979: TMC0923 chip, Itron FG85C1 tube, a 61.4 kHz charge pump to -22 V from a 9 V battery, and a 7 V 1.5 kHz square-wave filament supply.
- That New Idea from EAI
A four-page EAI promotional brochure advertising new analog computer developments, digital data reduction equipment, and analog plotters and recorders. Featured products include the new 221A Analog Computer, Model 2301 Electronic Digital Voltmeter, Automatic Digital Input-Output System (ADIOS), Quad Amplifier Package, Magnetic Tape Dataplotter, Transistorized Variplotter, and Portable DVM. The back page highlights EAI Computation Centers in Princeton, Los Angeles, and Europe, and describes custom engineering services in control instrumentation, system analysis, and development engineering.
- The "Tunny" Machine and Its Solution
Tiltman's account of the 30 August 1941 depth and the reconstruction of the Lorenz SZ40/42, with a worked example on real April 1944 wheel patterns. NSA DOCID 3838610.
- The Advanced User Guide for the BBC Micro
§18.9 light pens: 6845 registers R16/R17 and the per-mode correction factors.
- The American Vine-Dresser s Guide Being a Treatise on the Cultivation of the Vine and the Process of Wine Making
- The Analog Computer
A five-page magazine article from Electronics and Technology Today (August 1988) that introduces analog computing to a general technical audience, covering the history from mechanical to electronic machines and a comparison of analog versus digital computing. The article details the three core computing elements (coefficient multiplier, summer, integrator) and demonstrates problem setup and patching using the classic mass-spring-damper car suspension model. The author also describes a custom analog computer designed and built at Aberdeen University, including its modular panel architecture, color-coded patch sockets, BBC Micro interface for hybrid operation, and precision power supply design.
- The Antikythera Mechanism, Rhodes, and Epeiros
Festschrift chapter summarising Iversen's case for a Rhodian maker, an Epirote calendar and the 205 BC epoch.
- The Antikythera Mechanism: Evidence of a Lunar Calendar
Horological Journal, December 2020. Hole positions under the calendar ring, pointing to ~354 days rather than 365.
- The Armourer's Handbook, Part II — Machine Carbines and Pistols (Labore, Gale & Polden)
A wartime Gale & Polden (Aldershot) handbook for unit armourers and inspecting officers. Opens with the STEN Mk II (and an illustration of the Mk III): detailed stripping, examination and what-to-look-for notes, followed by the Thompson, the Lanchester and the No. 1 and No. 2 pistols.
- The Armoury of His Grace the Duke of Buccleuch and Queensberry (Wilcock, Arms & Armour, 2012)
A survey of the Buccleuch family's historic armoury published in the Royal Armouries journal Arms & Armour 9(2), pp. 181–205 (author's version). The Puckle Gun dive cites it for the two Puckle guns in the collection, the drum magazine at Boughton and the third example in Copenhagen.
- The ARRL Antenna Book (24th Edition)
- The Art and Mystery of Making British Wines, Cider, Perry Cordials and Liquors--Also, the Whole Art of Brewing
- The Art of Brewing - 2nd ed
- The Art of Brewing and Fermenting in the Summer -- and the Making of Malt
- The Automatic Telephone
Museum booklet explaining automatic telephony and its history.
- The Brewer A Familiar Treatise on the Art of Brewing with Directions for the Selection of Malt and Hops--and the Making of Cider and Wine
- The Cause and Prevention of Acidity in Malt Liquors
- The Chain Rule
A two-page lecture note presenting the Chain Rule for differentiating composite functions. It states the rule formally, works through multiple examples including polynomial, trigonometric, and nested compositions, and demonstrates a step-by-step decomposition method. The document also illustrates applying the Chain Rule using tabular function values rather than closed-form expressions.
- The Closet of Sir Kenelm Digby Openend Several Ways of Making Metheglin, Cider, Cherry-Wine, etc
- The Colmar Incident: A Cryptographic Device Lost in World War II Operations
Loss of a 28th Infantry Division SIGABA at Colmar, Feb–Mar 1945; search, recovery from the Giessen, photos of the recovered machine (4 pp.) [writer A]
- The Compleat Brewer or, the Art and Mystery of Brewing Explained
- The Complete Distiller
- The Complete English Brewer or, the Art and Mystery of Brewing in All its Various Branches
- The Complete Practical Brewer or, Plain Accurate , and Thorough Instructions in the Brewing of Ale, Beer, and Porter
- The Complete Practical Brewer or, Plain Accurate , and Thorough Instructions in the Brewing of Ale, Beer, and Porter
- The Computer Museum Report vol. 4, Spring 1983 — incl. “D. H. Lehmer's Number Sieves”
Includes R. Rubinstein's article on D. H. Lehmer's number sieves and their reproduction for The Computer Museum.
- The Cultivation of the Native Grape and Manufacture of American WInes
- The Culture of the Grape and Wine Making - 7th ed
- The Curta, a Technical Marvel
Herbert Bruderer's 2022 article on Curt Herzstark and the Curta, its manufacture in Liechtenstein, and what newly found patent documents and design drawings show about the Multiple Curta, a parallel calculator.
- The Distiller
- The Distiller s Guide Comprehending the Art of Distillation and Rectification
- The DIY STEN Gun (Practical Scrap Metal Small Arms Vol. 3)
Sheet-metal construction guide for a STEN-pattern submachine gun.
- The Early Model Personal Computer Contest (The Computer Museum Report, 1986)
The Computer Museum's report on its 1986 contest, which judged the KENBAK-1 the first personal computer.
- The Early Years of the Strowger System
History of the first Strowger exchanges 1891-1900s.
- The Enfield Weapon System — Royal Ordnance Sales Brochure (c. 1985)
Royal Ordnance's sales brochure for the Enfield Weapon System: construction, ammunition, sights, bayonet, scabbard and accessories. Cited by the SA80 dive.
- The Experienced Beekeeper
- The Factorization of the Ninth Fermat Number (Math. Comp. 61, 319–349)
The first factorisation by the number field sieve.
- The Fascinating Tale of the Fowler Magnum Pocket Slide Rule
Short history of Fowler and a scale-by-scale description of the 4⅝-in Magnum Long Scale: ring-by-ring radius and circumference table (six-ring long C totalling 49.5 in; outer short scale 13.4 in), the two Magnum layouts (L scale outside or inside the long scale), gauge marks, and the two-knob operation (top crown over the red datum line turns the dial; the 2 o'clock knob turns the black cursor).
- The First Americans: The 1941 US Codebreaking Mission to Bletchley Park (Special Series vol. 12)
The Sinkov–Rosen–Weeks–Currier mission with the PURPLE analog, Friedman's illness, crates memo (64 pp); cited throughout the PURPLE unit but not yet in the Library
- The First and Second Derivatives
A three-page calculus lecture note explaining the geometric and analytical meaning of the first and second derivatives of a function. Topics covered include increasing/decreasing behavior, concavity, the second derivative test for classifying critical points as local maxima or minima, and inflection points. The exposition uses polynomial examples to illustrate each concept.
- The First Book of KIM (1977)
Programs, games and tutorials for the KIM-1, from Hayden's 1977 collection.
- The First Patent Machine Gun – The Puckle Gun (McClain, ASAC Bulletin 126)
A collector's article in the American Society of Arms Collectors Bulletin 126 (pp. 64–67) on James Puckle's 1718 patent gun and the surviving examples. Used in the Puckle Gun dive as an attributed collector's secondary.
- The Fowler Calculators — a Catalogue Raisonné
The first systematic catalogue of 50 Fowler models and scale varieties, with the C-R numbering collectors still quote (2A…2F early 2½-in groups, 2M/3M/4M modern groups by diameter, G general / T textile / A artillery / N nautical / MT machine time / MP Mackay suffixes). Lists every model's circles front and back, the case construction by group, and the page count of each model's instruction booklet.
- The Friedman Legacy: A Tribute to William and Elizebeth Friedman (Sources in Cryptologic History No. 3; 3rd printing 2006)
Friedman's six 1963 lectures on cryptologic history, biographical sketch and bibliography, Callimahos's 'The Legendary William F. Friedman', Chiles's essay and the 1980 tribute to Elizebeth (226 pp, 33 MB, text layer)
- The Fundamental Theorem of Calculus
Section 4.3 from Dan Sloughter's open textbook 'Difference Equations to Differential Equations,' presenting both the Fundamental Theorem of Integral Calculus and the Fundamental Theorem of Differential Calculus with full proofs. The section demonstrates that integration and differentiation are inverse operations, shows how definite integrals may be evaluated using antiderivatives, and proves that every continuous function has an antiderivative constructible via a definite integral with variable upper limit. Worked examples and problem sets covering evaluation of definite integrals, derivatives of integral functions, and area computations are included.
- The Genuine Sieve of Eratosthenes (J. Functional Programming 19(1), preprint)
Shows that the well-known two-line functional "sieve" is really trial division, and gives a true Eratosthenes sieve using a priority queue.
- The Geometry of Graphs
Section 3.9 from Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations', covering the geometry of function graphs using first and second derivatives. The section explains concavity (concave up/down), inflection points, and a systematic method for sketching graphs by combining information from f, f', and f'' along with asymptote analysis. Worked examples include polynomial, rational, and transcendental functions with detailed sign analysis.
- The Hagelin Cryptographers — a review (1961, transcription)
Hagelin's 1961 review of his firm's machines, from Damm's A-21 to the C-series, transcribed at cryptocellar.org.
- The Heath Electronic Analog Computer: Its Usage for the Solution of Engineering Problems
A 1962 Master of Science thesis from Villanova University presenting a tutorial on electronic analog computation using the Heath Electronic Analog Computer, which features fifteen operational amplifiers, potentiometers, initial-condition power supplies, four relays with four transfer contacts each, and eight vacuum diodes operating in repetitive (0.6–6 cps) or non-repetitive modes. The thesis develops a systematic amplitude and time scaling methodology and demonstrates it through worked examples including second-order linear differential equations, simultaneous first-order systems, a servomechanism simulation, and a proposed frequency analyzer. Special circuits for multiplication, dead time, dead space, and hysteresis are also surveyed, and the Heath machine is assessed as an excellent educational introduction to analog methods.
- The House of the Dead 2 — Instruction Manual (Dreamcast, US)
Context for the North American Dreamcast gun situation.
- The HYCOMP Hybrid Analog/Digital Computing System
Sales and technical brochure for the HYCOMP Hybrid Analog/Digital Computing System, a joint offering from Packard Bell Computer and Computer Products, Inc. The system combines the CPI Mark III analog computer with the Packard Bell PB440 stored-logic digital computer, linked via a high-speed analog-digital conversion subsystem (up to 128 A/D channels at 25 Kcps, 128 D/A channels at 100 Kcps, 14/15-bit resolution, better than 0.05% accuracy), binary signal control/sense lines, and the DIDAC automatic remote I/O controller. The brochure covers system architecture, the HYCOMP I/O controller, conversion link specifications, software macro commands for hybrid operation, and application areas including aerospace simulation, sampled-data systems, and optimization.
- The Impact of Triangular-Toothed Gears on the Functionality of the Antikythera Mechanism
arXiv:2504.00327. Simulation arguing that manufacturing errors at estimated levels would jam the mechanism.
- The Independent Liquorist or, the Art and Manufacturing and Preparing
- The Index of Coincidence and Its Applications in Cryptanalysis (War Department, Office of the Chief Signal Officer, Technical Paper; NSA REF ID A64722)
Friedman's coincidence paper as reissued by the Signal Corps: Vogel quintuple-disk and Schneider ciphers solved by coincidence counts; footnote 1 says it revises the 1922 Riverbank paper (87 pp scan, declassified 2014)
- The Initial Calibration Date of the Antikythera Mechanism after the Saros Spiral Mechanical Apokatastasis
Almagest 14(1), 4–39 (arXiv:2203.15045). Proposes 22/23 December 178 BC as the starting date.
- The Inkeeper s and Butler s Guide , or, a Directory for Making and Managing British Wines - 13th ed
- The Inscriptions of the Antikythera Mechanism, 1: General Preface
Almagest 7(1). Introduction to the editio princeps of the inscriptions: the fragments, imaging and research history.
- The Inscriptions of the Antikythera Mechanism, 2: Historical Background and General Observations
Almagest 7(1). Letterforms, dating and the general character of the texts.
- The Inscriptions of the Antikythera Mechanism, 3: The Front Dial and Parapegma Inscriptions
Almagest 7(1). Zodiac and calendar dial labels and the parapegma star-calendar.
- The Inscriptions of the Antikythera Mechanism, 4: The Back Dial and Back Plate Inscriptions
Almagest 7(1). Metonic months, games dial and Saros eclipse glyphs.
- The Inscriptions of the Antikythera Mechanism, 5: The Back Cover Inscription
Almagest 7(1). The descriptive 'user's manual' text of the back cover.
- The Inscriptions of the Antikythera Mechanism, 6: The Front Cover Inscription
Almagest 7(1). The planetary text, including the 462 (Venus) and 442 (Saturn) year periods.
- The Lightning Calculator: Bonham, Hook and Pangborn
Otnes's history of the Lightning and its makers, from Grand Rapids and Los Angeles city directories, with photographs and X-rays of the machines. Journal of the Oughtred Society 11:1 (Spring 2002), pp. 53–58.
- The Mannheim Slide Rule (N4041): A Self-Teaching Manual with Tables of Settings, Equivalents and Gauge Points
K&E's full manual for its Mannheim rules with the 4041 scale set (A, B, C, D; S, L, T on the back of the slide) — the same scale set as the 4058C Beginner's rule. Covers reading, multiplication, division, proportion, squares and roots, the trig and log scales, and tables of settings and equivalents. 78 pp.
- The Manufacture of Cider and Perry
- The Manufacture of Cider and Perry - 2nd ed
- The Manufacture of Liquors, Wines, and Cordials without the Aid of Distillation
- The Manufacture, Imitation, Adulteration, and Reduction of Foreign Wines, Brandies, Gins, Rums, Etc
- The Many Lives of Herbert O. Yardley (Cryptologic Spectrum)
Profile of Herbert O. Yardley, the American Black Chamber and its reading of Japanese codes at the 1921–22 Washington Naval Conference.
- The Mauser C96 Explained
Illustrated reference on the Mauser C96 — field-stripping, takedown, and mechanism.
- The Mauser Self-Loading Military Pistol (Dunlap, ASAC 1969)
Arms & Armour Society journal article on the Mauser self-loading military pistol.
- The Mechanical Combination of Linear Forms (Amer. Math. Monthly 35, 114–121)
D. H. Lehmer's own description of the 1926–28 bicycle-chain sieve, including its parallel spring-contact stopping circuit.
- The Natural Logarithm Function (Section 6.2)
Section 6.2 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations,' covering the natural logarithm function as the inverse of the exponential function. The section derives properties of log(x) including algebraic identities, the derivative (d/dx log(x) = 1/x), integral formulas, the Taylor series expansion about x=1, and the power rule extended to irrational exponents. Worked examples include differentiation via the chain rule, integration by substitution (tan(x), sec(x)), integration by parts for log(x)dx, and graphical analysis of y = log(x).
- The Neglected Giant: Agnes Meyer Driscoll (Special Series vol. 10)
Full NSA biography of Driscoll: Riverbank 1920, CM device, Red/Blue Book, M-1, JN-25, Enigma, trainer of Navy officers
- The Nixie Tube: Design and Control — Reference Article
- The Notion of a Derivative and Cubic Functions
A two-page lecture handout covering the general definition of the derivative as the limit of a difference quotient, with graphical illustration of secant-line approximations to the tangent. It then introduces cubic functions f(x) = ax³ + bx² + cx + d, describes the three basic graph forms, and derives the formula df/dx(p) = 3ap² + 2bp + c, working through examples with g(x) = x³ + 3x and h(x) = x³ − 3x.
- The Picayune's Creole Cook Book (Fifth Edition)
The fifth edition (1916) of the New Orleans newspaper's landmark Creole cookbook, first published in 1901 and copyrighted 1901, 1906, 1910 and 1916. Forty-nine chapters run from Creole coffee and the gumbos through fish and shellfish, the meats, poultry and game, Louisiana rice, vegetables, the sweet courses, domestic wines and cordials, canning and pickling, Creole bread, and closing chapters of household suggestions and a month-by-month table of seasonable foods. Recipes are titled in English and French and set out with an ingredient list above the method. Its stated purpose was to write down the New Orleans kitchen before it was lost. It is the source of the oldest printed Creole recipe for pickled pork — given on page 70 as "Pickled Pork. — Petit Salé" and containing no vinegar at all, a dry salt-and-saltpetre barrel cure.
- The Pistol and Revolver (Himmelwright, 1908)
A period American handbook on pistol and revolver shooting by the president of the United States Revolver Association (1908 edition). The Borchardt C-93 research checked it as a period source; it only lists Borchardt among the makes of automatic pistol.
- The Pistols of Germany and Its Allies in Two World Wars, Vol. I
Reference volume covering German and allied service pistols, including the C96.
- The Polar Planimeter and Its Use in Engineering Calculations (Wheatley, 1903)
K&E's book on the polar planimeter: its theory, the zero circle, and its use for indicator diagrams, earthwork, reservoirs and other engineering calculations.
- The Polar Planimeter of Jakob Amsler (van der Salm)
A history and vector-analytic treatment of Amsler's polar planimeter and its precursors.
- The Polyphase Duplex Decitrig Slide Rule No. 4071: A Manual (1939 edition, with the later Manual No. 68 2055 edition covers)
The owner's manual for the K&E 4071-3 Polyphase Duplex Decitrig (sold 1939-1967), the model of Jeff's 4071-3 (s/n appears to be 640890, c. 1952). Includes the orange 1939 paper cover and the later green 'Slide Rule Manual' cover (No. 68 2055). Five chapters: multiplication and division (DF/CF folded scales); proportion and combined operations (CI, CIF); squares, cubes, roots and the L scale; plane trigonometry with the S, ST (Sine Tangent) and T scales, red numbers, law of sines and cosines, radians and vectors; logarithms and the slide rule, with a historical note and answers. 104 pp., image scan without text layer.
- The Power of Analogs
A 37-slide presentation by Bernd Ulmann (December 2010) tracing the history of analog computing from the Antikythera mechanism (~150 BC) through Lord Kelvin, Philbrick's Polyphemus, Hoelzer's Mischgeraet, and the NASA zenith era of the 1960s–70s, then examining the technology's decline and potential future revival. Covers the fundamental approach of indirect analogies — translating differential equations into electronic circuits — and argues that FPGA- or massively-parallel-chip-based digital implementations of analog computing elements could offer superior performance for dynamic-systems simulation. Illustrated with the Lorenz attractor as a worked example.
- The Practical Apiarian
- The Practical Bee-Master
- The Private Brewers Guide to the Art of Brewing Ale and Porter
- The Quick and Easy "Lawrence" Slide Rule Instruction Book (Simple Rules for Using the Slide Rule)
Lawrence's own instruction book for its A B CI C D K rules: the 'mental survey' and 'digit and integral digit' methods of placing the decimal point, multiplication, division, squares, cubes and their roots. 16 pp.
- The Scottish Ale-Brewer and Practical Maltster -- Including India Pale Ale
- The Secrets of the Mash Tun or, Causes of Failure in Producing Good Ale or Beer
- The Sega Light Phaser — Instructions
Light Phaser leaflet: Control 1 port, 4–6 ft range, lens care, serial-number warranty clause.
- The Selfloading Rifle HK91, Cal. .308 (Heckler & Koch leaflet)
H&K Oberndorf's six-page operator's leaflet for the HK91, the civilian semi-automatic G3 (pre-1990 address). The HK PSG1 dive cites it for the HK91 the US clone builds start from.
- The SIGABA / ECM II Cipher Machine: "A Beautiful Idea" (Timothy J. Mucklow)
Full history: Hebern, Friedman's M-134, Rowlett's stepping maze, the Navy, production, wartime security, key-space and mechanics appendices (52 pp.) [writer A]
- The Simulation of Transport Delay with the HYDAC Computing System
This two-page EAI bulletin (No. ALHC 64019, 1964) describes a hybrid computing technique for simulating transport delay on the HYDAC Computing System using analog-to-digital conversion, digital function storage, and logic components. The program supports up to ten independent delay channels with storage capacities of 16, 64, or 256 words per channel and variable delay times, overcoming the phase-error and multiplier-count limitations of classical Pade-polynomial analog approaches. Sample results for two-channel transport delay with a velocity step change are presented.
- The Sine and Cosine Functions
A calculus lecture note covering the graphs, properties, and derivatives of the sine and cosine functions, including periodicity, boundedness, amplitude, phase shifts, and evenness/oddness. The document derives that d/dx(sin x) = cos x and d/dx(cos x) = -sin x through graphical analysis of slopes and inflection points. Generalized forms A sin(kx) and A cos(kx) are examined, with formulas for amplitude |A| and period 2π/k, along with their derivatives.
- The Spirit, Wine Dealer, and Publicans Director
- The SRT Scale: Supplement to the Manuals on the 4081 Log Log Duplex Decitrig, 4083 Log Log Duplex Vector and 4071 Polyphase Duplex Decitrig Slide Rules
Six-page K&E supplement issued when the SRT scale replaced the ST scale (catalogue 1955b; on the rules c. 1956). Tells owners to read SRT wherever their manual says ST; revised Section 38 'Radians. Small Angles' (replaces 4081 manual sections 37-38 and 4071 manual sections 39-40): SRT is a C scale graduated 0.573-5.73 degrees so that an angle in degrees on SRT reads in radians on C; worked examples (3.56 deg = 0.0621 rad), exercises and answers.
- The step-by-step telephone switching system: Digit absorbing selectors
Digit absorbing selectors.
- The step-by-step telephone switching system: Handling of toll calls
Toll calls in SxS offices.
- The step-by-step telephone switching system: Overview
Clear modern explanation of SxS for novices and practitioners.
- The step-by-step telephone switching system: Reverting calls
Reverting calls on party lines.
- The step-by-step telephone switching system: The connector switch
Connector operation in detail, with test-stand photo.
- The step-by-step telephone switching system: The line finder switch
Line finder operation in detail.
- The step-by-step telephone switching system: The selector switch
Selector operation in detail.
- The Sterling Submachine Gun — Dillon Blue Press, August 2011
An unsigned one-page article in Dillon Precision's Blue Press catalogue-magazine (August 2011, p. 41) on the Sterling submachine gun. Used by the Sterling Mk 7 dive as an attributed secondary.
- The Story of the Hagelin Cryptos
Hagelin's own memoir of AB Cryptograph, Damm, the B-21, C-35/C-38, the M-209 and Crypto AG.
- The Strowger System (chapter, Beginnings of Automatic Telephony)
Scholarly history of the Strowger system's invention and development.
- The Stunt Box Teletype Corporation 1959
42 code slots, function bars and tines, selective calling, applications. 20 pp
- The Sum of a Sequence
Section 1.3 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations' introduces the concept of infinite series as limits of partial sums. The section develops the theory of geometric series, derives the closed-form sum formula for |r| < 1, and demonstrates applications including probability problems (coin tossing, animal reproduction), the economic multiplier effect, and the divergence of the harmonic series.
- The Switching Place (Telecom Information Kit No. 3)
Illustrated introduction to exchange history from manual to Strowger to crossbar.
- The TELEFUNKEN RA 741 Analog Computer
A first-person restoration account of a TELEFUNKEN RA 741 analog computer, originally rescued from the University of Aachen. The article details repair of the power supply (including the ±10 V precision reference regulators and the 400 Hz chopper/synchronous-rectifier system), the 15 Germanium auto-zero operational amplifiers (including substitution of OPA27 ICs for failed Germanium circuits), the timing/control relay section, and the removable patch panel. Dated February 2006 / January 2008 and attributed via contact email to [email protected].
- The TELEFUNKEN RA 742 Analog Computer
A single-page illustrated article from the Analog Museum describing the TELEFUNKEN RA 742 transistorized tabletop analog computer, covering its three-drawer architecture (power supply, function generators, and patch/control panel), and key specifications: 25 chopper-stabilized op-amps with 10^8 open-loop gain, four parabola multipliers, two diode function generators, 20 coefficient potentiometers, removable patch panel, and a total weight of 105 kg. The author also documents the experience of diagnosing and repairing the precision dual-rail +/-10 V power supply, and two sample calculations performed after restoration.
- The Telefunken RA 770 Analog Computer
A first-person account (dated December 2007) of acquiring, restoring, and documenting a Telefunken RA 770 high-precision analog computer (accuracy 10^-4, weight ~550 kg). The article describes mechanical and electrical restoration after rodent damage, and covers major subassemblies including dual power supplies, the DBG 771 digital control drawer with oven-stabilized quartz oscillator, chopper-stabilized OP14 operational amplifiers, servo potentiometers for coefficient setting, non-linear network drawers (NNT 771), variable function generators (VFG 801), and the coaxial analog patch field.
- The TELEFUNKEN RAT 700 Analog Computer
A descriptive overview article about the TELEFUNKEN RAT 700 desktop analog computer, introduced in 1961, featuring 19 operational amplifiers (15 chopper-stabilized), two variable diode function generators with 21-segment piecewise-linear approximation, four multipliers, and twenty 10-turn coefficient potentiometers. The article details the machine's four-drawer construction, patch panel wiring scheme, control panel functions (continuous, repetitive, and single-run modes), and internal circuit card design. Written by an analog computer enthusiast and collector at analogmuseum.org, with photographs and a historical reference to a 1965 magazine feature on a car suspension simulation using the RAT 700.
- The Teletype Model 28 RT Set Teletype sales brochure 1950
Reperforator-transmitter set for message relaying. 6 pp
- The Teletype Story Teletype Corporation 1957
Company history to 1957; Model 28 design brief, dates, stunt box. **Second tag:** Teletype-Machines, Teletype-Model-15
- The Theory and Practice of Brewing (3rd ed)
- The Theory and Practice of Brewing (4th ed)
- The True Amazons or, the Monarchy of Bees -- Also, how to make the English Wine or Mead
- The Unbelievable Zombie Comeback of Analog Computing
A long-form WIRED feature article (May 2023) by Charles Platt examining whether analog computing is experiencing a genuine renaissance. The article surveys historic analog devices, interviews researchers at Mythic, IBM, Columbia University (Yannis Tsividis, Glenn Cowan, Ning Guo), and MIT (Sara Achour), and traces the development of chip-scale hybrid analog-digital computers such as the HCDC. It concludes that energy efficiency demands from AI workloads—where the human brain operates on approximately 20 W versus megawatts for digital equivalents—are the primary driver for renewed interest, and that differential-equation fluency will be a key skill for any analog computing revival.
- The Unique Lawrence (version 9)
History and model catalogue of Lawrence Engineering Service (Wabash 1935–38, Peru from 1938) and Engineering Instruments Inc.: the family history, the standard 12-inch blanks and fixed stock dimensions, the decoding of model numbers (8-B = 8-inch stock, type B Enhanced Mannheim A/B, CI, C/D, K), PAT. PEND. markings, OEM and themed rules, with picture galleries. Originally in the Proceedings of IM2011 (Oughtred Society); updated 2017.
- The Very First TELEFUNKEN Analog Computer
A photo-essay and technical description of the RA 1, the first analog computer built by TELEFUNKEN, developed around 1955-1956 by Dr. Kettel, Dr. Schmidt, Dr. Kley and others. The machine is a three-rack, electron-tube system with a +/-100 V machine unit, featuring diode function generators, parabola multipliers (using EAA91 tubes), coefficient potentiometers, summers/integrators, dual oscilloscopes, and a precision system timer. The article details the operating principles of the parabola multiplier (exploiting the identity xy = ((x+y)^2 - (x-y)^2)/4) and the integrator state machine, and notes the absence of a central patch panel in favor of per-drawer front-panel interconnects.
- The Vine and its Fruit
- The Vine-Dresser s Manual an Illustrated Treatise on Vinyards and Wine-Making
- The Vintner s and Brewer s Guide--Manufacturing Wines, Malted Liquors, Cider, Perry, Vinegar, Spirits, etc
- The Vintner s Guide
- The Violent Crime Reduction Act 2006 (Realistic Imitation Firearms) Regulations 2007 (SI 2007/2606)
The UK colour and size rules for imitation firearms. Original print PDF.
- The Wine Drinkers Manual
- The Wine Merchant s Manual A Treatise on the Fining, Preparation of Finings, and General Management of Wines
- Theoretisch-Praktische Bierbrauerei Nach Ihrer Ersten Entwicklung Bis Zum Jetzigen Standpunkte
- Theory and Practice of Brewing With Malted and Unmalted Corn
- Think Analog
A 65-page slide presentation delivered by Bernd Ulmann at the Humboldt University Berlin Medientheorien colloquium on 27 May 2009. The talk introduces analog computation through direct and indirect analogies, walks through worked examples (bouncing ball, Joukowski wing simulation), contrasts the structural programming model of analog computers with stored-program digital machines, and concludes with a forward-looking discussion of digital-analog hybrid architectures using FPGAs and GPUs as high-speed analog processors.
- Think-a-Dot Instructions
Instruction booklet for E.S.R.'s Think-a-Dot logic puzzle.
- TI ADC0808-N/ADC0809-N 8-Bit µP-Compatible A/D Converters with 8-Channel Multiplexer — Datasheet (SNAS535H)
The ratiometric potentiometer input on Operation Thunderbolt's board.
- TI BQ25756 1–14-Cell Bidirectional Buck-Boost Battery Charge Controller — Datasheet (SLUSEN5A)
The on-board PD-input charger option.
- TI BQ76952 3S–16S High Accuracy Battery Monitor and Protector — Datasheet (SLUSE13B)
The high-side protector step-up option.
- TI BQ769x0 (BQ76920/30/40) 3S–15S Battery Monitor Family — Datasheet (SLUSBK2I)
Monitor alternative considered.
- TI BQ77904/BQ77905 3S–20S Ultra Low-Power Stackable Li-Ion Battery Protector — Datasheet (SLUSCM3K)
The picked pack protector.
- TI DRV110 Current Controller for Solenoids, Relays and Valves — Datasheet (SLVSBA8G)
PWM peak-and-hold current controller: fast ramp to a peak current, then a lower hold current to cut dissipation.
- TI DRV120 Relay, Solenoid and Valve Low-Side Driver with Current Regulation — Datasheet (SLVSBG3C)
Integrated low-side peak-and-hold solenoid driver with its own switch and recirculation path.
- TI DRV2605L 2- to 5.2-V Haptic Driver for LRA and ERM with Effect Library — Datasheet (SLOS854D)
Overdrive and braking, the ERM effect library, LRA auto-resonance 125–300 Hz.
- TI DRV5023 Digital-Switch Hall-Effect Sensor — Datasheet (SLIS151G)
Unipolar digital Hall switch, 2.5–38 V; the stock-firmware trigger sensor and pin-compatible with the DRV5056.
- TI DRV5055 Ratiometric Linear Hall-Effect Sensor — Datasheet (SBAS640C)
Bipolar ratiometric linear Hall sensor with a VCC/2 offset; the rejected alternative to the DRV5056 for the analogue trigger.
- TI DRV5056 Unipolar Ratiometric Linear Hall-Effect Sensor — Datasheet (SBAS644C)
Unipolar linear Hall sensor with a 0.6 V offset, running from 3.3 V or 5 V; the sensor chosen for the analogue Hall trigger.
- TI DRV8251A 4.1-A Brushed DC Motor Driver with Integrated Current Sense and Regulation — Datasheet (SLVSFU6)
H-bridge driver with an IPROPI current mirror and internal current regulation, 50 V absolute maximum; the regulated solenoid stage of the reference board.
- TI DRV8874 H-Bridge Motor Driver With Integrated Current Sense and Regulation — Datasheet (SLVSF66A)
H-bridge driver with current sense and regulation; the rejected alternative to the DRV8251A for the solenoid stage (40 V absolute maximum).
- TI ISO1540/ISO1541 Low-Power Bidirectional I2C Isolators — Datasheet (SLLSEB6F)
The isolator in proposal AH-5.
- TI LM1881 Video Sync Separator — Datasheet (SNLS384G)
The classic composite sync separator (Last Time Buy status noted in the dive).
- TI LM393 Dual Differential Comparator
General-purpose comparator option for the sieve builds' sensor circuits.
- TI LM5060 High-Side Protection Controller — Datasheet (SNVS628H)
Rail switch: enable behaviour and quiescent current.
- TI LM66100 5.5-V 1.5-A Ideal Diode with Input Polarity Protection — Datasheet (SLVSEZ8A)
Ideal-diode ORing (WP-8).
- TI LM74700-Q1 Low-IQ Reverse Battery Protection Ideal Diode Controller — Datasheet (SNOSD17G)
Ideal-diode pair for a two-source supply (WP-3 alternative).
- TI LMH1981 Multi-Format Video Sync Separator — Datasheet (SNLS214H)
The proposed sync separator for an RP2040 console box (OC-2).
- TI OPA380 / OPA2380 Precision High-Speed Transimpedance Amplifier — Datasheet (SBOS291G)
The reference transimpedance amplifier for a CRT-timing photodiode front end.
- TI OPT101 Monolithic Photodiode and Single-Supply Transimpedance Amplifier — Datasheet (SBBS002B)
Integrated photodiode plus TIA, used as the counter-example (too slow for raster timing).
- TI SR-10 Owner's Manual
Texas Instruments' owner's manual for the SR-10, its first slide-rule calculator.
- TI SR-50 Owner's Manual
Texas Instruments' owner's manual for the SR-50 scientific calculator.
- TI SR-51 Owner's Manual
Texas Instruments' owner's manual for the SR-51 and SR-51A.
- TI TLV3501 4.5 ns Rail-to-Rail High-Speed Comparator
Fast comparator for the gear sieve's photodiode detector.
- TI TMS 1000 Series Data Manual (December 1976)
TI's data manual for the TMS1000 microcomputer family, including the high-voltage TMS1070 and TMS1270 that drive fluorescent displays directly, with a strobed VFD interconnect diagram.
- TI TMS0117 Arithmetic Processor Datasheet
Datasheet of the TMS0117, a member of TI's TMS0100 single-chip calculator family: pinout, timing and functions.
- TI TPS2116 1.6–5.5 V 2.5-A Low-IQ Power Mux — Datasheet (SLVSFG1A)
Power mux for the Stage 2 board (WP-8).
- TI TPS2550 / TPS2551 Adjustable Current-Limited Power-Distribution Switches — Datasheet (SLVS736C)
Adjustable current-limited switch; also the source of the USB 2.0 power rules quoted (100 mA, 44 Ω ‖ 10 µF).
- TI TPS2552 / TPS2553 Precision Adjustable Current-Limited Power-Distribution Switches — Datasheet (SLVS841F)
Precision current-limited USB power switch, up to 1.5 A.
- TI TPS25750 USB Type-C and USB PD Controller — Datasheet (SLVSFR7A)
The NRND predecessor; EEPROM configuration facts.
- TI TPS25751 USB Type-C and USB PD Controller with Integrated Power Switches — Datasheet (SLVSH93A)
The proposed in-gun sink (UP-6).
- TI TPS26750 USB Type-C and USB PD (EPR) Controller — Datasheet (SLVSH67)
EPR controller; the on-board charger reference.
- TI TPS55340 Integrated 5 A Wide-Input Boost/SEPIC/Flyback Regulator — Datasheet (SLVSBD4E)
40 V / 5 A integrated-switch boost regulator; the candidate for raising USB power to a solenoid voltage.
- TI TUSB321 USB Type-C Configuration Channel Logic and Port Control — Datasheet (SLLSEO6C)
Type-C CC logic; source for the Type-C current-advertisement levels.
- TI UCC27517A Single-Channel High-Speed Low-Side Gate Driver — Datasheet (SLUSBQ0C)
4 A peak low-side gate driver; the gate driver of the reference solenoid stage.
- TI-30 Owner's Manual (1976)
Texas Instruments' owner's manual for the original LED TI-30 of 1976.
- TI-30 SLR Owner's Manual
Texas Instruments' owner's manual for the TI-30 SLR.
- TI-30-II Owner's Manual
Texas Instruments' owner's manual for the TI-30-II.
- TI-30X IIS Reference Guidebook
Texas Instruments' reference guide for the TI-30X IIS two-line scientific calculator.
- TI-30X IIS Teacher Guide
Texas Instruments' teacher guide and activities for the TI-30X IIS.
- TI-30X MultiView Reference Card
Texas Instruments' quick-reference card for the TI-30X MultiView calculators.
- TI-30X Pro MultiView Guidebook
Texas Instruments' guidebook for the TI-30X Pro MultiView, the European twin of the TI-36X Pro.
- TI-30XS MultiView / TI-30XB MultiView Guidebook
Texas Instruments' guidebook for the TI-30XS MultiView, its first non-graphing calculator with a dot-matrix display.
- TI-30XS MultiView Teacher Guide
Texas Instruments' teacher guide for the TI-30XS MultiView, with classroom activities.
- TI-36X Pro Calculator Guidebook
Texas Instruments' guidebook for the TI-36X Pro: modes, MathPrint, memories, calculus, statistics and distributions, tables, matrices, vectors, solvers, number bases, constants, conversions, complex numbers and battery replacement, with worked examples.
- TI-36X Solar Guidebook
Texas Instruments' guidebook for the TI-36X Solar engineering calculator, the TI-36X Pro's predecessor.
- TI-55 Owner's Manual
Texas Instruments' owner's manual for the TI-55 programmable scientific.
- TI-81 Guidebook
The guidebook for the TI-81 of 1990, Texas Instruments' first graphing calculator (scanned).
- TI-82 Graphing Calculator Guidebook
The guidebook for the TI-82 of 1993, TI's second graphing calculator and the first with a link port.
- TI-83 Graphing Calculator Guidebook
The guidebook for the TI-83 of 1996, ancestor of the TI-83 Plus and TI-84 Plus.
- TI-83 Plus / TI-83 Plus Silver Edition Guidebook
The guidebook for the TI-83 Plus of 1999, TI's first graphing calculator with flash memory, and its Silver Edition.
- TI-83 Plus Developer Guide
TI's software development kit guide for writing assembly-language programs and flash applications for the TI-83 Plus.
- TI-83 Plus System Routines (Third Release)
TI's reference to the operating-system routines available to TI-83 Plus assembly programs, third release of 25 January 2002.
- TI-84 Plus and TI-84 Plus Silver Edition Guidebook
The complete guidebook for the monochrome TI-84 Plus and Silver Edition (OS 2.55MP), including batteries and the backup cell.
- TI-84 Plus C Silver Edition Guidebook
The complete 414-page guidebook for TI's first colour TI-84, with the same screen, keys and menus as the TI-84 Plus CE: graphing, tables, statistics, finance, matrices, programming, memory and accuracy.
- TI-84 Plus Family: Test Preparation, Press-to-Test
TI's one-page instructions for putting a TI-84 Plus family calculator into Press-to-Test exam mode and taking it out again.
- TI-85 Guidebook
The guidebook for the TI-85 of 1992, TI's graphing calculator for calculus and engineering (scanned).
- TI-86 Graphing Calculator Guidebook
The guidebook for the TI-86 of 1996, successor to the TI-85.
- TI-89 / TI-92 Plus Guidebook
The guidebook for TI's symbolic-algebra calculators, the TI-89 and TI-92 Plus.
- TI-89 Titanium Graphing Calculator Guidebook
The guidebook for the TI-89 Titanium of 2004, with its computer algebra system.
- TI-Basic Programming Guide for the TI-84 Plus CE Graphing Calculator
TI's TI-BASIC programming guide for the TI-84 Plus CE, with the CYLINDER getting-started program, every program command and the instructions for running assembly-language programs.
- TICOM DF-120: Report on the M-209 (German cryptanalysis)
German wartime technical report on the M-209 and its solution, translated for TICOM.
- TICOM I-175: Report by Alfred Pokorn of OKH/Chi on the M.209 (1945)
A German Army cryptanalyst's own account, written for TICOM, of how the M-209 was solved from depths and cribs.
- TICOM I-6: Interrogation of Lt. Muentz, OKM, on the M-209 (6 June 1945)
Interrogation of a German naval cryptanalyst on reading M-209 traffic.
- Time Crisis — Instruction Manual (PlayStation, PAL)
G-CON45 controls, calibration and the list of incompatible televisions.
- Time Crisis 3 — Instruction Manual (PlayStation 2, US)
GunCon 2 controls; a cross-check on the Time Crisis II booklet.
- Time Crisis II — Instruction Manual (PlayStation 2, US)
GunCon and GunCon 2 connection diagrams, the External Cable and USB port assignment.
- Tisch-Analogrechner: Beschreibung und Bedienungsanleitung (Desktop Analog Computer: Description and Operating Manual)
Description and operating manual (MV 2 460568, dated 1 March 1961) for the BBC desktop analog computer manufactured by Brown, Boveri & Cie in Mannheim. Covers fundamental principles of electronic analog computing including operational amplifiers, summation, integration, and coefficient potentiometers, followed by operating instructions for the specific machine.
- Tischanalogrechner und Zusatzgeräte — Kurzbeschreibung
A German-language brief description (Kurzbeschreibung) from AEG-TELEFUNKEN Datenverarbeitung covering two desktop analog computers — the RA 710 and RA 742 — along with four accessories: the DEX 109 digital voltmeter, MAT 740 patch-field networks, EVS 801 electronic resolver, and LZS 100 electronic audio output. Each section describes intended applications, special features, operating modes, computing elements, and a summary of functional counts (integrators, summers, multipliers, function generators). The document is a product overview rather than a detailed operator manual.
- TM 10-412 — Army Recipes
The U.S. War Department's official WWII cookbook, issued 15 August 1944 and superseding Chapter 2 of TM 10-405. Roughly 570 numbered recipes — beverages, breads, cakes and cookies, cereals, desserts, eggs, fish, fritters and croquettes, fruits, macaroni and rice, meat, pies, salads, sandwiches, sauces, soups and vegetables — each scaled to 100 servings and measured in Army kitchen units (No. 56 dippers, mess kit spoons, No. 10 cans). The source of the Army's canonical versions of dishes like creamed chipped beef on toast and Boston baked beans.
- TM 11-2111 Tools, Testing Equipment and Common Supplies, Step-by-Step Dial Central Office Equipment
Describes AE-supplied SxS test equipment: current-flow test set, stepping-switch test set (varying machine), test handset with switch test plug, test stand with 24-terminal jack, and the routine test procedures.
- TM 11-2222 Receiving Transmitter Distributors TT-12 FGQ-1 TT-13 FGC-1 and Transmitter Distribut Department of the Army TM 11-2222 1951
TM 11-2222, Receiving Transmitter Distributors TT-12/FGQ-1, TT-13/FGC-1 and Transmitter Distributors TT-21/FG, TT-25/FG, TT-26/FG, TT-52/FG (incl. other Model 14 TDs)
- TM 11-352 Technical Manual
TM 11-352, Technical Manual for Printers TG-7-A, TG-7-B & TG-37-B; Chests CH-50-A/B & CH-62-A/B
- TM 11-380: Converter M-209, M-209-A, M-209-B (Cipher), 17 March 1944
The US Army technical manual for the M-209: operation, key setting, the training key list and its check, key-list preparation, maintenance and destruction. NSA REF ID A67854.
- Tom Osborne's Story: the Green Machine and the HP 9100
Osborne's own account, written to Barney Oliver, of designing the Green Machine prototype and the HP 9100A.
- Toshiba BC-0801B Instruction Manual
The 10-page manual of the Toshiba BC-0801B desk calculator.
- Toshiba BC-0802 Calculator: Reverse-Engineered Schematic
Schematic of the Toshiba BC-0802 desk calculator of 1972 with NEC LD8035 or Toshiba fluorescent tubes.
- Toshiba BC-1212 Calculator: Reverse-Engineered Schematic
A 17-page schematic with state diagram of the Toshiba BC-1212 of 1970: MSI MOS logic and multiplexed NEC LD-955A Nixies, including the under-rated 0.022 uF digit-driver capacitors.
- Totzeitglied
Engineering report produced after a ten-week internship at Dornier Friedrichshafen (October 1971), describing a dead-time element add-on unit for the DO 80 analog computer. The unit implements variable delay (1 ms to 10 s) via an analog-to-digital conversion chain: input op-amp (AD 503) compresses ±10 V to 0–10 V, an ADC 540-8 digitises to 8-bit words, a 100-position Signetics 2510k shift register provides the programmable delay, and a DAC 371-8 with output op-amp reconstructs the ±10 V analog signal. A VCO (8038) clocks the chain at a rate controlled by a panel voltage, and control logic interfaces the unit to the DO 80 bus (Compute/Halt/Initial Condition modes). Detailed circuit analysis, component selection, calibration procedures, oscillograms, and a full schematic are included.
- Totzeitglieder für den DO 80 Analogrechner — Beschaffungs- und Entwicklungsunterlagen
A compilation of internal correspondence, technical descriptions, circuit diagrams, and supplementary material relating to the development and procurement of dead-time (Totzeitglied) plug-in modules for the Dornier DO 80 analog computer, dated 1973–1975. The core preliminary description documents an 8-bit A/D and D/A converter architecture with a 100-word shift register, providing adjustable dead-time delays from 1 ms to 10 s in three ranges, selectable via a continuously variable input; the module occupies one single-width DO 80 slot. Supporting material includes Siemens and Dornier procurement letters, internal distribution memos, Helipot resistor-network and AEG-Telefunken LZG 100 delay-unit data sheets, and an English-language Monte Carlo simulation article from Electronic Design (February 1973).
- TR-20 Computer Maintenance Series
Comprehensive maintenance manual for the EAI TR-20 analog computer, published August 1967 (Publ. No. 00 800.2006-0). The manual provides chapter-by-chapter circuit descriptions, technical data, patching procedures, test procedures, and troubleshooting guidance for every major TR-20 computing element including the dual DC amplifier (Model 6.712), dual integrator network (Model 12.1116), quarter-square multiplier (Model 7.045), diode function generators (X², log X, variable), coefficient attenuator groups, signal comparators, repetitive-operation and manual-mode control circuits, and regulated power and reference voltage supplies. Four appendices cover elementary analog-device principles, transistor and etched-board servicing techniques, replaceable parts lists, and engineering drawings.
- TR-20 Computer Operator's Reference Handbook
This handbook serves as an operator reference guide for the EAI TR-20 desktop analog computer, covering operating considerations, computing components, and patching procedures. It describes the operational amplifier, attenuators, quarter-square multiplier, diode function generators, variable diode function generators, signal comparators, function switches, and repetitive operation mode. Appendices provide computer symbols, circuits using computational components, amplifier circuits for simulating transfer functions, and a bibliography.
- Tractrices, Bicycle Tire Tracks, Hatchet Planimeters, and a 100-year-old Conjecture (2013)
American Mathematical Monthly 120 (2013): the hatchet planimeter and its connection with bicycle tracks.
- Transistorisierter Differentialanalysator MEDA 42 TA — Technische Beschreibung und Bedienungsanleitung
Technical description and operating instructions for the MEDA 42 TA transistorized differential analyzer, a laboratory-grade analog computer for solving systems of ordinary differential equations. Covers machine structure, power supply modules (±14 V, ±6 V, ±24 V, ±290 V rails), computing elements (10 integrators, 8 summers, 30 coefficient potentiometers, 1 quadratic function generator, 1 nonlinear function generator with 30 breakpoints, comparator), control panel operation, and operating modes (Prepare, Compute, Step, Read, Continuous). Includes schematics of power supply distribution and control plate circuitry.
- Transistorisierter Tisch-Analogrechner RAT 700 — Beschreibung und Bedienungsanleitung
Operator manual for the Telefunken RAT 700 transistorized desktop analog computer (Tisch-Analogrechner), covering mechanical construction, modes of operation, technical specifications, and operating procedures. The RAT 700 is a fully transistorized (solid-state) desktop analog computer configurable from a basic setup (10 amplifiers, 20 potentiometers) to a full configuration (19 amplifiers plus multipliers and comparators), featuring chopper-stabilized computing amplifiers with drift below 20 µV at 40°C and less than 0.1% error up to 100 Hz. The manual also addresses coefficient potentiometers, parabola multipliers, free diodes, function generators, Schmitt triggers, repetitive computation, maintenance procedures, and fault finding.
- Transistorisierter Tischanalogrechner RA 741 — Beschreibung
Operator description (Beschreibung) for the Telefunken RA 741 transistorized desktop analog computer. Covers technical overview, construction, component specifications (computing amplifiers, integrators, potentiometers, function generators, comparators), peripheral options, and a full table of base and optional configurations with prices in DM. Intended to inform users on operation, maintenance, and commissioning of the RA 741 analog computing system.
- Transistorisierter Tischanalogrechner RA 742 — Beschreibung
Comprehensive description and operating manual for the Telefunken RA 742 transistorized desk analog computer, covering technical overview, component complement (23 computing amplifiers in standard configuration, 19 coefficient potentiometers, multipliers, comparators, function generators), detailed technical specifications, and operating procedures. The document covers operation, maintenance, commissioning, and circuit descriptions, and notes that a separate computing guide is available for problem-solving methodology. Key specifications include ±10 V operating range, integrator drift below 50 µV/sec, and electronic integrator switching at 1 µs.
- Transistorisierter Tischanalogrechner RA 742 — Informationsblatt
AEG-Telefunken product information sheet for the RA 742 transistorized desktop analog computer, targeting university and industrial research computing centers. Covers key features, technical specifications (integrators, summers, function generators, parabolic multiplier, comparators, memory network), physical dimensions (670×550×500 mm, 105 kg), and a list of compatible add-on accessories including the DEX 102 digital add-on for hybrid computation.
- Trokhimenko and Lyubich, Microcalculator, Your Move! (1985, in Russian)
Mikrokalkulyator, vash khod! (Radio i svyaz', 1985, 224 pp, 100,000 copies): programming methods, games and models of moving vehicles for programmable calculators (in Russian).
- Trokhimenko et al., Programmable Microcalculators: Design and Use (1990, in Russian)
Programmiruemye mikrokalkulyatory: ustroistvo i pol'zovanie (Radio i svyaz', 1990, 272 pp): the main published account of the hardware and software of the B3-34 and MK-61 family (in Russian).
- TRS-80 PC-1 Pocket Computer and Cassette Interface Service Manual
Radio Shack's service manual for the TRS-80 Pocket Computer (26-3501) and Cassette Interface (26-3503), with Radio Shack part numbers: specifications, block diagram, signals, disassembly, cassette tests, check program, schematics and parts lists.
- TRS-80 PC-2 Operations Manual
The operations manual for the TRS-80 PC-2, Radio Shack's version of the Sharp PC-1500.
- TRS-80 PC-2 Printer/Cassette Interface Manual
The manual for the PC-2's printer, plotter and cassette interface (26-3605), the Sharp CE-150.
- TRS-80 Pocket Computer Engineering Math II
The manual for Radio Shack's Engineering Math II software for the Pocket Computer.
- TRS-80 Pocket Computer Games II Instruction Manual (26-3523)
The instructions for Radio Shack's Games II cassette for the Pocket Computer.
- TRS-80 Pocket Computer Games Instruction Manual (26-3515)
The instructions for Radio Shack's Games cassette for the Pocket Computer.
- TRS-80 Pocket Computer Owner's Manual
The 126-page owner's manual for the TRS-80 Pocket Computer (26-3501): manual calculation, programming in BASIC, the reservable keys, cassette commands, error codes, specifications and battery replacement.
- TRS-80 Pocket Computer Printer/Cassette Interface Manual (26-3505)
The manual for the 26-3505 Printer/Cassette Interface: docking, paper and ribbon, the Ni-Cd battery, the POWER, PRINT and REMOTE switches, printing with LIST and PRINT, and specifications.
- TRS-80 Pocket Computer Programs
Jim Cole's book of fifty ready-to-run programs in Pocket BASIC for business, education and fun, sold by Radio Shack (cat. no. 62-2066); also published by Artsoft.
- TRS-80 Pocket Computer Reference Card
The quick-reference card for the TRS-80 Pocket Computer: commands, statements, functions and error codes.
- TRS-80 Pocket Computer Statistical Analysis (26-3522)
The manual for Radio Shack's Statistical Analysis software for the Pocket Computer.
- Two Reasons Why a Controls Laboratory Needs an Analog Computer
A two-page trade article by R.H. Spiess of Comdyna, Inc. (Barrington, IL) arguing for the use of analog computers in controls laboratories. Covers two roles: the operational amplifier as a functional circuit element for teaching transfer functions, frequency response, and compensation design; and simulation of complete control systems using the Comdyna Analog Controls Simulation Manifold for dynamic testing and digital computer interfacing.
- Two Variable Function Generator Program for HYDAC
This two-page EAI bulletin (No. ALHC 64020) describes the F(x,y) HYDAC program, a hybrid-computer software routine that generates arbitrary functions of one or two variables using components of the EAI Digital Operations Systems (DOS). The program represents a function of one variable as 15 straight-line segments connecting 16 evenly spaced breakpoints, and extends this to two variables by defining multiple such curves at breakpoints in the second variable, with linear interpolation applied in both dimensions. Input is loaded from punched paper tape, enabling rapid setup; unused DOS components remain available for additional logic and computing tasks.
- Type 32A P-A-B-X modified for selective signaling — Automatic Electric (1939)
8 pp scan. Companion to Operating Bulletin 32A1 (already in Library)
- Type 37 Cordless PBX (brochure) — Automatic Electric (1954)
5 pp
- Type 616 Nixie Tube — Reference Document
- U.S. Army Air Corps Aerial Dead Reckoning Computer Type E-6B
Journal of the Oughtred Society 6:2 (1997), p. 32: the Army E-6B's scales, wind face and makers.
- Über die Nachbildung und Untersuchung von Abtastsystemen auf einem elektrischen Analogrechner
A 1960 journal article (reprint AH 507) by G. Schneider of the AEG Institute for Automation, Frankfurt, published in Elektronische Rechenanlagen Vol. 2, pp. 31–37. The paper presents a new method for simulating sampled-data (pulsed-data) systems on an electric analog computer, covering the construction of both sampling elements (using relays and RC circuits) and difference-equation elements (via cascaded sampling units acting as delay-line synthesizers). A detailed worked example demonstrates synthesis of optimal difference-equation compensators for finite-time settling of both reference and disturbance step responses, along with a general approach for solving arbitrary difference equations on the analog computer.
- Übersicht über die Technik der elektronischen Analogrechner
Introductory technical article by E. Kettel published in Telefunken-Zeitung (Vol. 30, June 1957, Issue 116, pp. 129–145) presenting a comprehensive overview of electronic analog computer technology. Covers computing elements (summation, integration, sign inversion, multiplication, function generation), the theory and implementation of drift-free DC operational amplifiers, and a detailed treatment of the diode-network parabolic multiplier used in Telefunken's own repetitive analog computer (with 22 sum/integrate units, 8 multipliers, ±100 V machine unit). Includes measured error data showing multiplier accuracy better than 0.2% with the described correction techniques.
- Ubhandlung uber die Kunft zu Brauen
- Ultimarc AimTrak Setup Guide
Setup manual for the AimTrak, a closed commercial light gun; the comparison point for the open firmwares.
- Ultimarc Bluetooth Light Gun (AimTrak Bluetooth) — Guide
Tested hosts (iOS, Android), HID-over-GATT, and no recoil on the Bluetooth kit.
- Umarex H&K MP7A1 (spring airsoft) — Operating Instructions 2.6486
Multilingual maker manual for the spring MP7A1: parts callout, cocking handle, loading, H&K licence statement. The only maker manual found for any airsoft MP7.
- UN Security Council S/2002/1115 — Report of the Panel of Experts on Liberia (2002)
The UN Panel of Experts' report on Liberia, transmitted to the Security Council on 25 October 2002. The Škorpion vz. 61 dive cites paragraphs 64–65 and Table 1, a consignment flown from Belgrade to Liberia that included 60 Yugoslav M84 machine pistols in 7.65 mm (the licensed Škorpion).
- Understanding Operational Amplifier Specifications
A Texas Instruments application report (SLOA011B, revised July 2021) by Jim Karki that explains how to interpret operational amplifier data sheet specifications. The document covers the ideal op amp model, non-inverting and inverting amplifier topologies, a simplified internal circuit diagram, and a detailed treatment of seventeen key parameters including input offset voltage, bias current, common-mode rejection ratio, slew rate, gain-bandwidth product, noise, THD+N, and settling time. It is intended to help engineers select op amps by understanding what published specifications mean and how TI defines and tests each parameter.
- Une nouvelle technique de calcul analogique — Le calculateur électronique
A French-language article by CSF describing their AC-based analog computation technique, in which voltages represent variables and cylindrical variable capacitors with servo motors replace conventional DC potentiometers. The article explains the three fundamental algebraic operations (multiplication by a constant, addition, and function evaluation), illustrates example calculator setups for coordinate transformation, differentiation, and integration, and concludes with an extended application to anti-aircraft (DCA) fire-control, showing how CSF analog computers track aircraft, compute firing solutions, and drive gun-laying systems.
- Uniden BCD396XT Digital Scanner — Complete Reference
Uniden's complete operating reference for the BCD396XT handheld DynamicDMA scanner: supported trunking systems (Motorola, EDACS, LTR, APCO P25 Phase I and one-frequency trunking), programming systems, sites, groups and channels, Close Call, band scope, tone-out, GPS features, wired cloning, battery charging, and specifications. Uniden's download page serves this reference in place of a printed owner's manual.
- Uniden BCD436HP / BCD536HP Digital Scanner — Owner's Manual
- Uniden BCD436HP / BCD536HP Digital Scanner — Owner's Manual (2024 edition)
Uniden's 2024 edition of the combined BCD436HP/BCD536HP owner's manual, as currently published on Uniden's download page: setup, controls, Wi-Fi dongle setup (BCD536HP), Sentinel, firmware and database updates, GPS, microSD card, and operation. Supersedes the 2013 edition also in this library.
- Uniden BCD536HP Wi-Fi Streaming & Remote Access via ProScan Web Server — Setup Guide
- Uniden Bearcat BC246T Scanner — Owner's Manual
- Uniden Bearcat BC350A Scanner — Owner's Manual
- Uniden Bearcat BC355N Scanner — Owner's Manual
- Uniden HomePatrol Extreme Edition (v2.02) — Owner's Manual
Guide to the paid HomePatrol Extreme upgrade: activating the registration key, Mass Storage vs Serial USB modes and serial drivers, front-panel programming of conventional and trunked systems, trunked system analyzers, EDACS/LTR LCN finder, band scope, RF power plot, trunking and conventional discovery, limit search, and raw data output. Written for the HomePatrol-1; the HomePatrol-2 Extreme feature set is the same.
- Uniden HomePatrol Scanner — Quick Reference Guide
Two-page quick reference for the HomePatrol main screen, status icons, setting location by ZIP code, selecting services, and common actions. Uniden serves this same guide for both the HomePatrol-1 and HomePatrol-2.
- Uniden HomePatrol-1 Scanner — Owner's Manual
- Uniden HomePatrol-2 (HomePatrol-II) Scanner — Owner's Manual
Owner's manual for the Uniden HomePatrol-II touchscreen digital scanner with built-in APCO P25 Phase I and Phase II decoding: setup, ZIP-code and GPS location, Favorites Lists, recording and replay, battery and USB power, and updating firmware and the weekly database with HomePatrol Sentinel.
- Uniden SDS100 / SDS200 Digital Scanner — Easier-to-Read Manual
- Uniden SDS100 / SDS200 Waterfall Feature — Operation Manual
- Uniden SDS100 Digital Scanner — Owner's Manual
- Uniden SDS200 Digital Scanner — Owner's Manual
- Unisonic 790R Instruction Manual
The 16-page manual of the Unisonic 790R pocket calculator, with NiCd, dry-cell and adapter operation.
- Universal Serial Bus Specification, Revision 2.0
The core USB 2.0 specification (usb_20.pdf from the USB-IF's 2025-06-03 package): cable impedance and delay, conductor resistance, VBUS and back-drive rules, suspend, bInterval.
- Untersuchungen über den Einfluß der Tanklage und nichtlinearer Dämpfungseffekte auf die Wirkung eines Schlingertanks
Technical report (Bericht Nr. 155) from the Institut für Schiffbau der Universität Hamburg investigating the influence of tank vertical position and nonlinear damping effects on the effectiveness of a Frahm-type passive anti-rolling tank aboard ships. The study develops dimensionless equations of motion coupling ship roll, tank water motion, and lateral (sway) motion, then uses an analog computer to simulate the nonlinear system and study parametric variations affecting roll amplitude reduction. Results show that positioning the tank above the ship's center of gravity improves anti-rolling effectiveness, and that optimal tank parameters depend substantially on ship form and heading angle.
- US 1,151,541 Calling Device for Automatic Telephone Exchanges
Later dial (calling device) patent, filed 1903.
- US 1,237,208 Automatic Telephone System
Keith system patent (filed 1908) on selector trunking.
- US 2,562,362 Testing System Employing Test Distributor and Test Connector Switches
AE test distributor/connector system.
- US 2,632,817 Testing Apparatus for Telephone Systems
Telephone test apparatus patent.
- US 3,600,525 Test Set for Strowger Switches
Portable Strowger switch test set design; comparison for the 26A.
- US 447,918 Automatic Telephone-Exchange
Strowger's founding patent.
- US 486,909 Automatic Telephone or Other Electrical Exchange
Strowger's improved exchange patent (vertical-and-rotary switch).
- US 597,062 Calling Device for Telephone Exchanges
The first rotary dial patent.
- US 638,249 Electrical Exchange
Keith/Erickson switch close to the modern step-by-step switch.
- US 815,321 Automatic Telephone Selector Switch
The two-motion selector switch patent.
- US Army Special Forces Foreign Weapons Handbook (1967)
The 385-page handbook compiled at Fort Bragg to teach Special Forces soldiers foreign small arms. It includes an entry on the 9 mm Mark V STEN (with notes on the Mk II and the mixing of parts between Marks) among the world's submachine guns. DTIC AD0867982, Distribution Statement A.
- US Design Patent D163,135: Pocket Adding Apparatus (K. R. Pangburn)
Design patent of 1 May 1951 for Pangburn's pocket adder, whose mechanism is virtually identical to the Lightning's.
- US Design Patent D163,136: Pocket Adding Apparatus Unit (K. R. Pangburn)
The companion design patent of 1 May 1951 for Pangburn's pocket adder.
- US Design Patent D251,979 — Hance, Automatic Firearm (1979)
Sydney R. Hance's US design patent for an automatic firearm, filed 6 June 1977 and published 29 May 1979; its six views show the outward form of the Enfield bullpup (identified by Ferguson as the finalised XL64E5), not its mechanism. Cited by the SA80 dive.
- US Patent 1,011,617: Calculating-Machine (C. Hamann, the proportional lever)
Hamann's proportional lever for the Mercedes-Euklid, filed 28 June 1910 and granted 12 December 1911 (DE 209,817).
- US Patent 1,142,896 — Lewis, Automatic Firearm (1915)
Isaac N. Lewis's automatic firearm patent, filed 16 April 1912 and granted 15 June 1915, assigned to the Automatic Arms Company of Buffalo. The Lewis Gun dive cites it for the gun's mechanism as patented.
- US Patent 1,355,417 — Pedersen, Firearm (1920)
John D. Pedersen's firearm patent, filed 28 April 1917 and issued 12 October 1920, one of the four patents behind the Pedersen Device. Cited by the Pedersen Device dive.
- US Patent 1,355,418 — Pedersen, Mechanical Movement (1920)
John D. Pedersen's "mechanical movement" patent, filed 29 May 1917 and issued 12 October 1920, one of the four patents behind the Pedersen Device. Cited by the Pedersen Device dive.
- US Patent 1,355,419 — Pedersen, Firearm (1920)
John D. Pedersen's firearm patent, filed 7 June 1917 and issued 12 October 1920, one of the four patents behind the Pedersen Device. Cited by the Pedersen Device dive.
- US Patent 1,355,420 — Pedersen, Firearm (1920)
John D. Pedersen's firearm patent, filed 12 July 1917 and issued 12 October 1920, one of the four patents behind the Pedersen Device. Cited by the Pedersen Device dive.
- US Patent 1,410,507: Calculating Machine (W. T. Ray)
Ray's stylus calculating machine, granted 21 March 1922, one of the dial adders related to the Lightning.
- US Patent 1,574,249: Adding Machine (R. W. Hook, the Lightning)
Hook's patent for the Lightning Adding Machine, filed 17 February 1921 and granted 23 February 1926: the actuators, numeral wheels, long carry tooth and weighted pawls of the stylus dial adder. The Dial-Adders theory volume uses its part numbers.
- US Patent 1,764,915: Calculating Apparatus (A. E. Vethe, the Addometer)
Vethe's Addometer patent, filed 10 September 1928 and granted 17 June 1930.
- US Patent 1,788,192: Computing Machine (C. Hamann, the Manus switching latch)
Hamann's switching-latch calculator with automatic division, filed 17 December 1925 and granted 6 January 1931; the US twin of DE 432,435. The Manus theory volume uses its part numbers.
- US Patent 1,829,379: Computing Machine (A. E. Vethe, the Addometer)
Vethe's computing-machine patent, filed in Oslo on 20 October 1926 and granted 27 October 1931.
- US Patent 1,940,069: Calculating Machine (J. H. Bair)
The Bair / Bair-Fulton adder, granted 19 December 1933: "essentially a Kummer" with an assisted manual carry, a borderline member of the stylus dial-adder type.
- US Patent 1,968,201: Calculating Machine (C. Hamann, the Automat)
Hamann's electric switching-latch machine with automatic multiplication, granted 31 July 1934.
- US Patent 10,535 — Smith & Wesson, Improvement in Magazine Fire-Arms (1854)
The 14 February 1854 patent stamped on every Volcanic barrel: the toggle-link lever action and carrier, drawn for a copper-cased Flobert-type cartridge with a case extractor rather than the Volcanic ball the guns actually fired.
- US Patent 11,314,339 B2 — Sinden, Control Device for Detection (2022)
Sinden's border-tracking patent.
- US Patent 12,005,347 B2 — Brown et al., In or Relating to Gaming Controllers (2024)
Sinden's solenoid-recoil patent, read against the D13 regulated recoil stage.
- US Patent 15,925 — LeMat, Revolver (1856)
LeMat's first US patent, 21 October 1856: the shot barrel serving as the cylinder arbor and a two-hammer cock. Witnessed by C. Girard, M.D.
- US Patent 2,007,082 — Griffith, Marksmanship Practicing Means (1935)
Filed 1934-04-12. The light-projecting practice rifle: a gun that fires a beam at photocell targets, the first light gun.
- US Patent 2,007,083 — Griffith, Shooting Gallery (1935)
Filed 1934-08-06. The coin-operated light-ray shooting gallery; four of its claims were pressed in Phoebus v. Ford Amusement Devices (1936).
- US Patent 2,013,603: Plotting and Computing Device (Philip Dalton)
Dalton's 1933 plotting and computing device: a compass plate over a rotating grid, for one-handed drift problems; granted 3 September 1935.
- US Patent 2,089,671 — Stecke, Automatic Firearm (1937)
Edward Stecke's automatic-firearm patent, filed 30 June 1934 and issued 10 August 1937. The HK PSG1 dive cites it in the prehistory of the roller-delayed action.
- US Patent 2,097,116: Plotting and Computing Device (Philip Dalton, E-6B)
The patent marked on wartime E-6Bs: a rotating plotting disc over a chart strip on rollers; filed 30 June 1936, granted 26 October 1937.
- US Patent 2,159,141 — Falkenberg, Electric Rifle Range (1939)
Filed 1937-01-11. The Rayolite range's drop-target mechanism.
- US Patent 2,181,948 — McClellan, Target Practicing Apparatus (1939)
Filed 1936-10-14. Multi-target photocell panel for a light-ray range.
- US Patent 2,450,668: Calculator (E. G. Kesling, the Kes-Add)
Kesling's pocket dial adder, filed 22 May 1944 and granted 5 October 1948.
- US Patent 2,510,831 — Patchett, Cartridge Magazine for Automatic Firearms (1950)
George Patchett's cartridge-magazine patent (British priority 18 April 1946; filed 16 April 1947; granted 6 June 1950), the Sterling's curved box magazine. Cited by the Sterling Mk 7 dive.
- US Patent 2,775,404: Navigational Computers (United Air Lines)
A circular navigational computer resolving airspeed into components; marked on Jeppesen's CR-2.
- US Patent 2,797,047: Calculator (O. Lehre, the Dial-A-Matic)
Lehre's Dial-A-Matic, granted 25 June 1957.
- US Patent 2,874,320: Indicating Device (H. J. Hampel, Burroughs Nixie)
The Burroughs stacked-cathode indicator tube, filed 13 December 1955 and granted 17 February 1959: photo-etched character cathodes, offset stacking for wide viewing, insulating light-absorbing rear coatings.
- US Patent 2,935,257: Releasable Restraining Device for Rotatable Parts of Calculators (E. G. Kesling)
Kesling's later patent for his pocket dial adder, filed 26 January 1955 and granted 3 May 1960.
- US Patent 24,312 — LeMat, Revolver (1859): the movable hammer head
LeMat's 1859 US patent for the movable hammer head that selects between the cylinder and the shot barrel, with wings that lock the cylinder — the selector on every surviving LeMat, which is not in the 1856 patent.
- US Patent 3,120,342 — Slide Rule (reactance and resonance decimal point locator)
Filed 16 Oct 1958 (Ser. No. 767,699), granted 4 Feb 1964, 16 claims. Covers the coarse decade-stepped scales with unit-labelled number rows and indicator arrows used on the back of the CIE/Pickett N-515-T to locate the decimal point in reactance and resonance problems. Two drawing sheets with worked settings (Figs. 3-5).
- US Patent 3,236,154 — Iwashita (Howa), Mechanism for Reducing the Rate of Fire in Automatic Firing Arms (1966)
Kenzo Iwashita's Howa patent (Japanese priority 28 June 1963; filed 16 April 1964; patented 22 February 1966) for the straight-line hammer rate reducer that slows the Type 64 rifle's cyclic rate. The Type 64 dive's source for the mechanism.
- US Patent 3,273,794: Mechanical Binary Digital Computer
The Digi-Comp I patent: filed 21 October 1963, granted 20 September 1966.
- US Patent 3,280,315: Key Controlled Decimal Electronic Calculating Machine (N. Kitz, Bell Punch, ANITA)
Kitz's ANITA patent, filed 29 December 1961 (priority 1957) and granted 18 October 1966: decade counting devices, nines-complement subtraction, multiplication by repeated addition and shifting, division by repeated subtraction, and an early brush-scanned version with numeral wheels.
- US Patent 3,283,435 — Koch (Heckler & Koch), Breech Closure (1966)
Theodor Koch's H&K breech-closure patent (German priority 30 October 1963; issued 8 November 1966) for the roller-delayed bolt. The HK PSG1 dive cites it for the G3-family bolt the PSG1 uses.
- US Patent 3,305,843: Display Apparatus (T. J. Scuitto, Wyle Laboratories)
The Wyle Scientific display, filed 16 December 1963 and granted 21 February 1967: digits drawn from gated sine and cosine arcs, timed from a cyclic memory.
- US Patent 3,388,384: Zero Suppression Circuit (General Micro-electronics, Victor 3900)
The Victor 3900's leading-zero suppression for its CRT display.
- US Patent 3,402,285: Calculating Apparatus (An Wang, logarithms)
Wang's logarithm method, filed 22 September 1964 and granted 17 September 1968: stored logs of 10, 2, 0.9, 1.01, 0.999 and 1.0001, factors of the form 1 +/- 10^-n applied by shift and add, with worked tables for ln 2.10 and the antilog of 4.23845.
- US Patent 3,430,095: Cathode Ray Tube Beam Positioning System Employing Composite Signals (Friden)
The SRI-developed Friden display, filed 8 July 1965 and granted 25 February 1969: staircase generators for position, a segment counter, weighted stroke origins and an oscillator sweep for the strokes.
- US Patent 3,446,114 — Ketterer (Heckler & Koch), Trigger Mechanism for Automatic Firearms (1969)
Wilhelm Ketterer's H&K trigger-mechanism patent, filed 18 December 1967 and issued 27 May 1969. The HK PSG1 dive cites it for the G3-family fire-control group.
- US Patent 3,453,601: Two Speed Arithmetic Calculator (Bogert and Miner, Victor 3900)
The Victor 3900's MOS calculator, running at 330 kHz to compute and 60 kHz to display, with stroke-drawn figure-8 digits.
- US Patent 3,454,785: Shift Register Employing Insulated Gate Field Effect Transistors (Norman, GME)
General Micro-electronics' dynamic MOS shift register, the memory of the Victor 3900.
- US Patent 3,508,101: Character Indicating Electron Tube (M. Tanji, Ise Electronics)
The basic vacuum-fluorescent display patent, filed 19 October 1967 (Japanese priority 27 March 1967) and granted 21 April 1970: fine oxide cathode, mesh grid, phosphor-coated segment anodes viewed through the cathode, about 0.8 V on the filament and +25 V on grid and anodes.
- US Patent 3,518,629: Recirculating Memory Timing (S. P. Frankel, Computron / SCM Cogito)
Frankel's recirculating-memory timing, from the design line that became the SCM Cogito 240.
- US Patent 3,523,282: Calculator (R. A. Ragen, Friden)
A second Ragen calculator patent, filed 24 September 1964 and granted 4 August 1970.
- US Patent 3,526,760: Square Root (R. A. Ragen, Friden EC-132)
The EC-132's square-root method by subtraction of successive odd numbers, filed 1 April 1966 and granted 1 September 1970.
- US Patent 3,546,676: Calculator (R. A. Ragen, Friden)
Ragen's master patent for the Friden electronic calculator, filed 29 October 1963 and granted 8 December 1970: recirculating memory, single-digit counters, the CRT display. Hundreds of drawing sheets.
- US Patent 3,566,160: Simplified Race-Preventing Flip-Flop (T. E. Osborne, HP)
The J-K flip-flop with selectable noise immunity used throughout the HP 9100.
- US Patent 3,566,745 — Jauch and Meidel (Heckler & Koch), Automatic Firearm Bipartite Semirigid Bolt (1971)
The H&K two-part bolt patent of Jauch and Meidel (priority 28 October 1967; issued 2 March 1971). The HK PSG1 dive cites it for the bolt head and carrier relationship.
- US Patent 3,588,873: Information Display Apparatus (Osborne, Magleby, Lukes, HP)
The HP 9100 display, filed 12 November 1968 and granted 28 June 1971: figure-8 characters from E- and I-shaped sweeps, narrow-character centring, grouping in threes, mains-locked refresh.
- US Patent 3,599,221 — Baer, Recording CRT Light Gun and Method (1971)
Filed 1968-03-18. The first television light-gun patent: a photocell gun that detects a spot on a CRT.
- US Patent 3,623,156: Calculator Employing Multiple Registers and Feedback Paths (T. E. Osborne, HP)
Osborne's calculator architecture patent behind the 9100: power gating, subroutine control and the integrated CRT pattern.
- US Patent 3,634,666: Electronic Desk Top Calculator Having a Delay Line and Automatic Decimal Alignment (Friden)
A division of Ragen's master patent: the delay-line organisation, register roles and automatic decimal alignment.
- US Patent 3,643,364 — Koch, Rifled Gun Barrel with a Curvilinear Polygon Cross-Section (1972)
Theodor Koch's polygonal-rifling patent (continuation of 26 September 1967; issued 22 February 1972). The HK PSG1 dive cites it for the H&K polygonal barrel.
- US Patent 3,654,612: Display System Using a Cathode-Ray Tube (Takachiho Koheki, Descal)
The Descal ASI-500 display: slope and step sweeps with a ROM blanking the unused parts of each digit.
- US Patent 3,723,789: Flat Composite Fluorescent Display Tube (M. Tanji, Ise Electronics)
Ise's multi-digit fluorescent tube patent, filed 8 December 1970 (Japanese priority 13 December 1969) and granted 27 March 1973: several digits in one envelope with common segment wiring and a grid per digit.
- US Patent 3,728,480 — Baer, Television Gaming and Training Apparatus (1973)
Filed 1971-03-22, a continuation of a 1968-01-15 application. The Odyssey-era television game patent; Fig. 4 is the light-gun circuit.
- US Patent 3,736,693 — Koch (Heckler & Koch), Firearm Barrel (1973)
Theodor Koch's H&K patent on the fluted chamber (chamber relief grooves) of the roller-delayed guns (German priority 8 March 1967; issued 5 June 1973). The HK PSG1 dive cites it for why the chamber is fluted.
- US Patent 3,778,778: Calculator with Self-Synchronous Recirculating Memory (Friden)
The delay-line timing of the Friden calculators: a gated clock resynchronised by a sync pulse on every pass, the 16-column, 6-register, 16-bit data train, and pulse-count digits.
- US Patent 3,786,295: Anode Substrates for Multi-Digit Fluorescent Display Tubes (Ise Electronics)
Ise's patent on the thick-film printed anode plate of the flat multi-digit tube, filed 20 October 1972 and granted 15 January 1974.
- US Patent 3,803,834: Wristwatch Calculator (Time Computer, Pulsar)
Time Computer's wristwatch calculator: filed 6 February 1973, granted 16 April 1974; shared display, conductive-plastic or stylus keys.
- US Patent 3,819,921: Miniature Electronic Calculator (Kilby, Merryman and Van Tassel)
Texas Instruments' patent on the hand-held electronic calculator, the Cal-Tech: priority 13 May 1971, granted 25 June 1974.
- US Patent 3,863,060: General Purpose Calculator with Capability for Performing Interdisciplinary Business Calculations (Hewlett-Packard, HP-80)
The HP-80 patent: filed 30 October 1972, granted 28 January 1975; TVM keys, bonds, depreciation, dates, statistics.
- US Patent 3,924,111: Electronic Calculators for Navigational Purposes
An early hand-held electronic calculator for navigation; filed 25 September 1974.
- US Patent 3,928,960: Combination Wristwatch and Calculator (Time Computer, Pulsar)
Filed 28 March 1974, granted 30 December 1975: 20-key conductive-plastic keypad, CMOS clock chip with 32,768 Hz crystal and P-MOS Cal-Tex CT-5007 calculator chip, solar recharging.
- US Patent 3,946,218: Calculator ... for Performing Yield-to-Maturity of a Bond Calculation (Hewlett-Packard, HP-80)
HP-80 divisional on bond yield-to-maturity: filed 10 October 1974 (priority 1972), granted 23 March 1976.
- US Patent 3,955,074: Calculator with Keys Having More Than One Function Assigned (Hewlett-Packard, HP-80)
HP-80 divisional on the shift key; granted 4 May 1976.
- US Patent 3,979,057: Electronic Navigational Computer (Specialized Electronics Corp.)
The Navtronic patent licensed on Sporty's E6B: a calculator chip driven by a program ROM, with prompt lamps; filed 29 October 1974, granted 7 September 1976.
- US Patent 3,979,058: Operator Prompting System for Stored Program Calculator (Specialized Electronics Corp.)
Prompting the operator for each input in words or lit legends; filed 17 March 1975, granted 7 September 1976.
- US Patent 3,997,994 — Kästner et al. (Heckler & Koch), Shoulder Arm with Swivel Breech Member (1976)
H&K's G11 rotating-breech patent, issued 21 December 1976. The Hyper-Burst Mechanisms dive cites it for the G11's swivelling chamber.
- US Patent 4,019,037: Electronic Wristwatch Incorporating Calculator (Suwa Seikosha)
Japanese priority 27 December 1971, granted 19 April 1977: a calculator watch with numbers entered by a rotating ring; the earliest calculator-watch priority found.
- US Patent 4,041,295: Electronic Timepiece Calculator (Suwa Seikosha)
Priority 7 November 1973, granted 9 August 1977: a calculator watch with a reduced keyboard, the time-setting keys doubling as calculator keys.
- US Patent 4,055,757: Calculator Apparatus with Annuity Switch for Performing Begin- and End-Period Annuity Calculations (Hewlett-Packard, HP-22)
The BEGIN/END switch: filed 27 August 1976, granted 25 October 1977.
- US Patent 4,062,181: Combination Watch-Calculator Construction (Hughes Aircraft)
Hughes Aircraft's calculator-watch construction with push-button contact springs: filed 16 January 1976, granted 13 December 1977.
- US Patent 4,074,351: Variable Function Programmed Calculator (Boone and Cochran)
Texas Instruments' patent on a single-chip programmed calculator: filed 24 February 1977, granted 14 February 1978.
- US Patent 4,078,327 — Möller and Ketterer (Heckler & Koch), Automatic or Semi-Automatic Small Arm (1978)
H&K's patent on the G11's recoiling-assembly small arm (German priority 8 October 1975, P 25 44 995; issued 14 March 1978). The Hyper-Burst Mechanisms dive cites it for how the G11 fires a three-round burst before the recoil reaches the shooter.
- US Patent 4,081,716: Fluorescent Display Elements (S. Uemura, Ise Electronics)
Ise's patent on fluorescent display elements, granted 28 March 1978, cited by the IEEE Milestone proposal as the basis of the active VFD.
- US Patent 4,106,677: Wrist Wearable Electronic Device with an Engagedly Stored Selected Tool (Hewlett-Packard)
The HP-01's stylus stored in the band clasp: filed 19 August 1976, granted 15 August 1978.
- US Patent 4,109,315: Wristwatch Calculator with Selectively Scanned Keyboard (Hewlett-Packard)
HP-01 keyboard scanning patent: filed 30 August 1976, granted 22 August 1978.
- US Patent 4,110,967: Method and System for Driving a Liquid Crystal Display Device
Static and matrix (multiplexed) drive on one LCD for a watch, with 128 Hz and 32 Hz drive derived from 32,768 Hz (priority 2 September 1975).
- US Patent 4,129,983: Liquid Crystal Digital Display Electronic Wristwatch (Suwa Seikosha)
Watch liquid-crystal mixtures, thresholds and drive (priority 21 November 1974).
- US Patent 4,158,285: Interactive Wristwatch Calculator (Hewlett-Packard)
The HP-01 patent: filed 9 February 1976, granted 19 June 1979; 38.4 kHz crystal divided to 800 Hz, keyboard matrix, sleep mode and interactive functions.
- US Patent 4,282,595: Digital Frequency Trimming of an Oscillator in an Electronic Timepiece (Timex)
Timex's pulse-deletion trimming: the crystal runs fast and a stored correction deletes pulses every 32 seconds; filed 21 December 1979, granted 4 August 1981.
- US Patent 4,395,045 — Baer, Television Precision Target Shooting Apparatus and Method (1983)
Filed 1980-06-16. A raster-timing light gun that reports the hit position, with an infrared link back to the console.
- US Patent 4,430,531: Snap Disc Keyboard (Hewlett-Packard, Voyager)
The Voyager series' snap-disc keyboard: filed 15 March 1982, granted 7 February 1984.
- US Patent 4,435,728 — Raven and Annegarn, Field Frequency-Doubling Circuit for a Television Signal (1984)
The 100 Hz field-memory television that breaks raster-timed light guns.
- US Patent 4,443,775 — Fujitani et al., Solenoid Actuator (1984)
Slits in the solenoid frame against eddy-current loss.
- US Patent 4,516,862: Electronic Timepiece Having Address Designation Circuits of ROM and RAM (Daini Seikosha)
A watch microprocessor: 32 kHz crystal, clocks to 4 kHz, about 240 µs machine cycle, 128 × 4-bit RAM; priority 4 June 1982.
- US Patent 4,526,477: Piezoelectric Buzzer for Wrist Watches (Daini Seikosha)
Piezo buzzer mounting and two-tone drive divided from 32,768 Hz; case-back resonance 4–10 kHz; granted 2 July 1985.
- US Patent 4,527,096: Drive Circuit for Capacitive Electroluminescent Panels (Timex)
Timex's EL backlight driver: 1.5 V boosted and reversed to 60–100 V peak to peak across a 2 cm² lamp; filed 8 February 1984, granted 2 July 1985.
- US Patent 4,529,322: Booster Circuit for Electronic Watch Elements (Seiko Instruments)
One boosting coil for both an EL lamp (about 100 V at 1,024 Hz) and a piezo buzzer, from a 1.57 V cell; granted 16 July 1985.
- US Patent 4,794,553: Compact Electronic Calculator Having Graph Display Function (Casio)
Casio's patent on the graphing calculator, the fx-7000G's method: priority 24 May 1985, granted 27 December 1988.
- US Patent 4,821,228: Method and Apparatus for Computation Stack Recovery in a Calculator (Hewlett-Packard)
Hewlett-Packard's patent on saving the stack so that an UNDO key can restore it: priority 24 December 1986, granted 11 April 1989.
- US Patent 4,831,538: Hand-held Navigation and Flight Performance Computer (ASA)
ASA's menu-driven flight computer with cursor selection and prompted inputs; filed 8 December 1986.
- US Patent 4,845,652: Generic Equation Solver Interface for Solving Mathematical Equations (Hewlett-Packard)
Hewlett-Packard's patent on the menu-key equation solver: priority 29 May 1986, granted 4 July 1989.
- US Patent 414,959: Adding Machine (C. H. Webb, improved)
Webb's improved adder, filed 28 April 1888 and granted 12 November 1889.
- US Patent 5,210,708: Compact Electronic Calculator Equipped with Graphic Display Function (Casio)
Casio's patent on shading the area of a definite integral on a calculator graph: priority 28 November 1990, granted 11 May 1993.
- US Patent 5,309,815 — Möller et al. (Heckler & Koch), Firearm, Particularly Handgun (1994)
H&K's handgun patent, German priority 25 March 1991 and issued 10 May 1994, covering the USP-family design that the Mark 23 grew from, including the recoil-reduction system. The HK Mk23 dive cites it for the mechanism.
- US Patent 5,377,130: Method and Apparatus for Solving Terms of a Numerical Sequence (Texas Instruments)
TI's patent on calculating and graphing sequences: priority 26 January 1993, granted 27 December 1994.
- US Patent 5,532,946: Calculator with Table Generation Capability (Texas Instruments)
TI's patent on the TABLE feature of its graphing calculators: priority 29 September 1993, granted 2 July 1996.
- US Patent 5,701 — Hunt, Loaded Ball (1848): the Rocket Ball
Walter Hunt's 1848 patent for the 'loaded ball' — the hollow-based Rocket Ball with its powder charge sealed by a perforated cap, ignited by the gun's own primer. The ancestor of the Volcanic ball.
- US Patent 5,739,823: Graph Display Devices (Casio)
Casio's patent on plotting each function in a user-chosen colour: priority 12 August 1994, granted 14 April 1998.
- US Patent 5,825,124 — Ohno et al., Cathode-Ray Tube Having Activated Green and Blue Phosphors (1998)
Includes a table of P22-type phosphor afterglow, used for decay times in CRT Timing Vol 2.
- US Patent 547,454 — Schmeisser, Recoil-Operated Firearm (1895)
Louis Schmeisser's recoil-operated firearm patent, granted 8 October 1895 and assigned to Theodor Bergmann: the design behind the Bergmann 1894–1896 pistols. The Bergmann 1896/1897 dive cites it for the mechanism's origin and the Schmeisser–Bergmann relationship.
- US Patent 571,260 — Borchardt, Recoil Magazine-Pistol (1896)
Borchardt's US patent for the C-93, issued 10 November 1896: the moving-barrel toggle-locked action, the closing spring, magazine and lock, with three drawing sheets (closed and open sections).
- US Patent 6,175,625, "Control Circuits for Electric Coding Machines" (L. F. Safford, D. W. Seiler)
The ECM Mark II's control circuits: controller, zeroizer, index maze, printer (14 pp., 5 drawing sheets) [writer A]
- US Patent 6,603,445 B1 — Factoring Large Numbers with Optoelectronic Devices (TWINKLE)
Patent for TWINKLE, the optoelectronic factoring sieve; the source of its figures.
- US Patent 6,771,252: Shading of Inequalities on a Graphing Calculator (Texas Instruments)
TI's patent on showing inequalities as shaded regions on a small screen: priority 20 December 2000, granted 3 August 2004.
- US Patent 6,867,777: Tracing and Storing Points of Interest on a Graphing Calculator (Texas Instruments)
TI's patent on moving the trace cursor between points of interest such as intersections and storing them: filed 20 December 2000, granted 15 March 2005.
- US Patent 6,869,285 B1 — Jones, Training Firearm (2005)
Filed 2003-06-11. A training pistol with CO2 gas recoil and a mechanically switched laser.
- US Patent 689,255: Adding-Machine (J. J. Walsh, the Calcumeter)
Walsh's Calcumeter, filed 16 January 1901 and granted 17 December 1901: a straight row of identical stylus dials with a latch carry, the first commercial success of the type.
- US Patent 7,210,411 — Booth, Smith and Ashley (BAE Systems), 4.6 mm Small Arms Ammunition (2007)
BAE Systems' patent (GB priority 27 March 2003; granted 1 May 2007) for a hard steel 4.6 mm projectile with a copper coating thick enough that the rifling engraves only the coating. The HK MP7 dive's source for the armour-piercing 4.6 × 30 bullet's construction.
- US Patent 7,927,216 B2 — Ikeda et al., Video Game System with Wireless Modular Handheld Controller (2011)
The last live member of the Wii Remote patent family (to 2027-10-25).
- US Patent 710,411 — Bergmann, Firearm (1902)
Theodor Bergmann's firearm patent, filed 15 October 1901 and issued 7 October 1902, covering his locked-breech pistol design. The Bergmann 1896/1897 dive cites it for the No. 5 / 1897 locking system.
- US Patent 747,585 — Browning, Automatic Firearm (1903)
John M. Browning's automatic-firearm patent, filed 3 April 1902 and granted 22 December 1903: the blowback pocket-pistol layout of the FN 1903 and Colt 1903, from which the Eibar Ruby derives. The Ruby Pistol dive compares the Ruby with it, including the grip safety and safety lever the Ruby drops or moves.
- US Patent 75,322: Improvement in Adding-Machines (C. H. Webb)
Webb's adder of 10 March 1868: two concentric stylus wheels, 00 to 99 and hundreds. The first dial adder to sell in quantity in America.
- US Patent 753,414 — Luger, Recoil-Loading Small-Arms (1904)
Georg Luger's US patent for the redesigned toggle-locked pistol that grew out of the Borchardt C-93, issued 1 March 1904; describes the 'knee-press' toggle resting slightly below centre.
- US Patent 8,499,014: Functionality Disable and Re-enable for Programmable Calculators (Texas Instruments)
TI's patent on Press-to-Test, disabling a calculator's programs and applications for an exam: filed 1 June 2005, granted 30 July 2013.
- US Patent 8,982,050 B2 — Solomon and Kisacanin, Motion Compensation in an Interactive Display System (2015)
Imperceptible complementary positioning targets flashed in the displayed image for a camera pointer.
- US Patent 816,591 — McClean, Automatic Gas-Operated Firearm (1906)
Samuel McClean's gas-operated firearm patent, filed 5 April 1898 and granted 3 April 1906, assigned to the McClean Arms and Ordnance Company of Cleveland. The Lewis Gun dive uses it for the McClean design the Lewis grew out of.
- US Patent 832,666: Calculating-Machine (C. Hamann, the Gauss)
Hamann's round calculating machine, the Gauss, filed 28 March 1905 and granted 9 October 1906 (DE 194,527).
- US Patent 845,747: Calculating-Machine (W. R. Bonham)
Bonham's stylus dial adder, filed 20 November 1905 and granted 5 March 1907: a row of dials with two reversed rings of numerals for adding and subtracting. The Lightning's direct ancestor.
- US Patent 897,688: Resetting Device for Adding-Machines (J. J. Walsh)
The Calcumeter's reset wheel, filed 29 November 1907 and granted 1 September 1908.
- US Patent 908,731: Calculating-Machine (W. R. Bonham, carrier-disk carry)
Bonham's second patent, filed 6 April 1905 and granted 5 January 1909: the carrier-disk tens carry between the stylus dials.
- US Patent 97,780 — LeMat, Revolver (1869)
LeMat's 1869 US patent, from the cartridge era of the design.
- US Reissued Patent RE45,905 E — Ikeda et al., Video Game System with Wireless Modular Handheld Controller (2016)
Reissued 2016-03-01 with a broad claim 1; expired 2026-09-15.
- USB Type-C and USB Power Delivery: Designing for both Extended Power Range and Battery-Powered Systems (SSZTD49A)
TI technical article on SPR/EPR fixed voltages and EPR cable and mode requirements.
- User Handbook, Sterling Sub-Machine Gun 9 mm Mk 4 (L2A3) — Sterling Armament Co.
Sterling Armament's user handbook for the Mk 4 (L2A3) sub-machine gun, in the edition whose "Brief history" (signed DTEH 1984) lists the Mark 6, Mark 7 and Mark 8. The Sterling Mk 7 dive takes its definition of the Mark 7 Para Pistol from it; the E-11 dive cites it for the donor Sterling.
- Using and Programming the Psion Organiser II
A book on using and programming the Psion Organiser II in OPL.
- v. Mannlichers Selbstlade-Karabiner und Karabiner-Pistole m/1901 (Wille, 1902)
Wille's 1902 German description of Ferdinand von Mannlicher's self-loading carbine and carbine-pistol m/1901: mechanism, hammer lock, hold-open, the Mannlicher-Pieper charger and the parts. The Mannlicher 1901/1903 dive's primary source; it shows that the pistol collectors call the M1903 is Wille's Karabiner-Pistole m/1901.
- Vacuum Fluorescent Displays: From Single Digits to Colour TV (Displays, 1983)
Ise's own account of the VFD: construction of filament, grid, phosphor and envelope, the oxide cathode at 650 C, ZnO:Zn response times, and the brightness curves against filament voltage, anode and grid voltage and duty, from single digits to colour panels.
- VERO Analog-Computer AC 46093 — Application Electronics
German-language operator manual and application guide for the VERO AC 46093 analog computer, a compact briefcase-form educational machine developed by BICC-VERO in collaboration with Hochschule Bremen. Covers operating modes (IC/OP/POT), computing elements (6 integrators, 3 summers, 3 difference amplifiers, 2 multipliers, 12 coefficient potentiometers, 4 diodes), technical specifications, master-slave linking of multiple units, and an applied example of DC motor speed-control simulation.
- Versuchsbeschreibung: Anwendung des Servo-Multiplizierers / Aufbau und Wirkungsweise eines PID-Reglers
A two-part German-language application note (January 1972, document numbers A 1357 and A 1360) from PEK Electronic describing laboratory experiments for the PEK Analogrechner Typ 38500 series. Part 1 covers the theory and hands-on exercises for the servo-multiplier (Type 38507), including multiplication, squaring, and division circuits with step-by-step measurement tables. Part 2 addresses the construction and operation of a PID controller implemented on the analog computer, including damped and growing oscillation experiments recorded via X-Y plotter.
- Versuchsbeschreibungen: Summierung und Integration mit dem Analogrechner (Versuche 2)
A January 1972 set of structured laboratory exercise guides (Versuchsbeschreibungen) for the PEK analog computer system, covering three experiments: summation with the analog computer (Experiment II), integration (Experiments II/III), and solving an integral equation. Each exercise provides a circuit description, required modules list (types 38013, 38501–38509), step-by-step measurement procedure, and data tables for recording results. Intended for students learning to configure the PEK modular analog computer's program panel for basic mathematical operations.
- VF Display Fundamentals (Allegro MicroSystems application note)
How a vacuum-fluorescent display is driven: static and multiplexed drive, filament supply and bias, blanking and capacitive loads, and VF driver ICs.
- Victor Medalist 204 Calculator: Reverse-Engineered Schematic
Schematic of the Victor Medalist 204 of 1976: Rockwell A4540CB single chip, discrete PNP drivers to -55 V, Futaba 13-MT-26 tube with 4.6 V DC filament, 136 Hz scan.
- Virtua Cop — Instruction Manual (Sega Saturn, US)
Stunner controls, GUN ADJUST and accuracy advice.
- Vishay BPV10NF Silicon PIN Photodiode — Datasheet (Rev 2.3)
Fast PIN photodiode with a daylight-blocking filter; the IR Point Tracking bench photodiode.
- Vishay BPW34 / BPW34S Silicon PIN Photodiode — Datasheet (Rev 2.1)
7.5 mm² PIN photodiode: the CRT Timing reference sensor, and a rejected alternative in IR Point Tracking.
- Vishay BPW41N Silicon PIN Photodiode — Datasheet (Rev 1.6)
Side-view PIN photodiode with daylight filter; a rejected alternative.
- Vishay Data Formats for IR Remote Control (doc 80071, Rev 2.3)
Remote-control carrier frequencies and burst timing: what an IR light-gun sensor must coexist with.
- Vishay TEPT4400 Ambient Light Sensor — Datasheet (Rev 1.8)
Phototransistor comparison part: slower than a PIN photodiode.
- Vishay TSAL6200 940 nm Infrared Emitting Diode
The 940 nm IR LED light source chosen for the gear sieve build.
- Vishay TSHG6400 High-Speed 850 nm Infrared Emitting Diode — Datasheet (Rev 1.5)
5 mm 850 nm IR emitter, ±27°; the emitter for the PixArt path.
- Vishay TSOP382.. / TSOP384.. IR Receiver Modules for Remote Control Systems — Datasheet
Demodulating IR receiver; test wavelength 950 nm.
- Vogel Analog Computer Schaltplan (Circuit Diagrams)
Two-page German-language schematic document for a Vogel analog computer, containing circuit diagrams for core computing elements (summers, integrators, inverters, multiplexer, diode function generator for sine approximation) and support circuits (DC/DC power converter, triangle wave generator, reference voltage supply, coefficient potentiometers, overload and polarity indicators, precision rectifier for meter display, and address selector switch). Primary op-amp used is the LF353 dual JFET-input device; precision reference is the REF01.
- Voyage 200 Graphing Calculator Guidebook
The guidebook for the Voyage 200, TI's QWERTY-keyboard symbolic-algebra calculator descended from the TI-92.
- W. F. Friedman, "Contributions in the Fields of Communications Security and Communications Intelligence" (REF ID A60528)
Summary version of the above; patent applications 682,096 and 70,412; SIGABA at Hyde Park and Yalta (6 pp.) [writer A]
- W. F. Friedman, "Important Contributions to Communications Security, 1939–1945" (REF ID A60534)
Friedman's own account of M-134/M-134-A, the Rowlett idea (15 Jun 1935), the Navy's Teletype contract (Jan 1938), the 3 Feb 1940 demonstration, Army procurement figures, M-228, M-138 (13 pp.) [writer A]
- Wang 300 Series Electronic Calculator Instruction Manual, Volume 1 (1968)
The 84-page operator's manual for the Wang 300, 310, 320, 360 and 362: installation, the work register, two adders and log register, every key with worked examples, accumulator switches, storage registers, trigonometric keyboards, card programming and the item counter.
- Wang 320K Keyboard/Display Unit: Reverse-Engineered Schematic
A 3-page schematic of the Wang 320K keyboard and display unit of the Wang 300 series: the key encoder, the diode-matrix Nixie decoder, cathode and anode drivers on +250 V, and the connector pinouts to the electronic package.
- Wang 500 Schematic
Factory schematics of the Wang 500 programmable calculator.
- Wang 700 A/B Manual
The 96-page manual for the programmable Wang 700A and 700B calculators.
- Wang 720A/B Reference Manual (1970)
The reference manual for the programmable Wang 720A and 720B, with Nixie display.
- Wang Laboratories Catalog and Price List (November 1968)
Wang's product catalogue and price list of November 1968: the 300 series packages and keyboards, programmers, the 700-series precursors, peripherals and prices.
- Wang LOCI Service Manual
The factory service manual for the Wang LOCI logarithmic calculators: logic, timing, the core store, power supply and maintenance.
- Wang LOCI-2 Reference Manual (December 1966)
The 108-page LOCI-2 reference manual: the W, A and L registers, logarithmic multiplication and division, storage registers, the program counter and card programs, decisions, loops, subroutines, Newton's method, and diagnostics.
- WCH CH224 USB PD Sink Controller — Manual 1, v2.1 (Chinese)
CH224K/D/Q/A and CH221K configuration tables and ratings (in Chinese).
- Weapon-Ammunition-System G 11 — English Brochure (Heckler & Koch / Dynamit Nobel)
H&K's English sales brochure for the G11 caseless weapon-ammunition system, with the Sterling, Virginia address (print code read as 10.88). Cited by the Hyper-Burst Mechanisms dive for the G11's specifications and by the Daisy dive for its 450 rpm figure.
- What Is a Hybrid Computer and Why
A short introductory article explaining the rationale for hybrid computing, contrasting analog and digital techniques, and describing a specific hybrid installation comprising EAI PACE 231R and 221R analog computers interfaced to a 4130 digital computer. The document lists the component inventory of the hybrid system (integrators, multipliers, potentiometers, function generators, A/D and D/A converters, logic trunks) and illustrates a practical application: using the hybrid system to model and optimise an industrial chemical process without interrupting production.
- Whistler Remote Control Protocol, CC Dump Protocol & Audio File Header Format v1.7 (WS1080/WS1088, WS1095/WS1098, TRX-1, TRX-2)
Whistler's serial command reference, version 1.7 (1 August 2017), for the WS1080/WS1088, WS1095/WS1098, TRX-1 and TRX-2 over USB: remote-control commands (key presses, status, LCD and active-channel readout), the control-channel (CC) dump format for trunked and conventional data, and the header format of the scanner's audio recordings.
- Whistler TRX-1 — Quick Start Guide
The single-sheet quick start guide packed with the TRX-1 handheld: batteries and the battery-type switch, antenna, and step-by-step programming of a county's services from the built-in EZ Scan library.
- Whistler TRX-1 Digital Handheld Scanner — User Guide
Whistler's full user guide for the TRX-1 digital handheld: object-oriented scanning, setup, programming from the EZ Scan library or by hand, conventional and trunked-system objects, DMR/MotoTRBO and NXDN, scanlists and priority, Spectrum Sweeper and searching, recording, IF output and settings.
- Whistler TRX-1E & TRX-2E — International Band Plans Addendum (CPU 7.4)
Addendum for the international TRX-1E and TRX-2E (CPU version 7.4): the frequency coverage, step sizes and service-search bands of each country bandplan, including the UK, Ireland, Australia, New Zealand, South Africa, India, Israel, Turkey and twelve European countries.
- Whistler TRX-2 — Quick Start Guide
The single-sheet quick start guide packed with the TRX-2 base/mobile scanner: package contents, mounting bracket, antenna and AC power, and step-by-step programming from the built-in EZ Scan library.
- Whistler TRX-2 Digital Base/Mobile Scanner — User Guide
Whistler's full user guide for the TRX-2 digital base/mobile scanner: desktop and vehicle installation with the remote head, programming from the EZ Scan library or by hand, conventional and trunked objects, DMR/MotoTRBO and NXDN, scanlists, Spectrum Sweeper and searching, recording, IF output and settings.
- Whistler WS1080/WS1088 EZ Scan Digital Handheld Scanner — Owner's Manual (Part 1)
First half (pp. 1–35) of the owner's manual for the WS1080/WS1088 digital handhelds: package contents, scanning legally, setup and controls, the EZ Scan library and PC software, and creating conventional and trunked-talkgroup objects. Continued in Part 2.
- Whistler WS1080/WS1088 EZ Scan Digital Handheld Scanner — Owner's Manual (Part 2)
Second half of the owner's manual for the WS1080/WS1088 digital handhelds, from editing objects onward: scanlists, searching, recording and playback, weather monitoring and SAME alerts, settings, troubleshooting and frequency coverage. Begins where Part 1 ends.
- Whistler WS1095/WS1098 EZ Scan Digital Base/Mobile Scanner — User Guide
Whistler's user guide for the WS1095/WS1098 digital base/mobile scanners: desktop and vehicle installation with the remote head, programming from the EZ Scan library or by hand, conventional and trunked objects with P25 Phase II, scanlists, Spectrum Sweeper and searching, recording, IF output and settings.
- Wire Communication Pamphlets 2, 7 and 11 (incl. No. 11 Elements of the Automatic Telephone System)
Bound set; Pamphlet 11 explains the AE private automatic exchange connector circuit step by step.
- Wirkungsweise des ungarischen Kommandogerätes GAMMA-JUHÁSZ
A detailed 28-page technical study (Winter 2014/15) by André Masson describing the design and operation of the Hungarian GAMMA-JUHÁSZ mechanical analog fire-control computer, which was adopted by Switzerland from 1937 and built under license by HASLER. The document covers the machine's geometric (non-Cartesian) computation principle, its ~400 kg gear-train architecture, form-body nonlinear function generators, electrical servo-tracking (micrometer) circuits, speed measurement subsystems, and successive model variants (Kgt. 38, 40, 43, 50), comparing the GAMMA-JUHÁSZ approach with the competing SPERRY system.
- Wolf River Coils Silver Bullet 1000 TIA — Portable Antenna Guide
- Workshop – Analog Computing
Slide deck from the 'Analog Computing' workshop held at VCFE-2006 in Munich, presented by Bernd Ulmann. Covers hands-on analog computer programming through three worked examples of increasing complexity: a mass-spring-damper system, Volterra predator-prey (rabbit-lynx) coupled differential equations, and a bouncing ball in a box with elastic reflections, friction, and gravity. All examples were patched and run on real Telefunken RA741/RA742 hardware; circuit diagrams, scaling considerations, and oscilloscope output photos are included throughout.
- Worldsemi WS2812B-V5 Intelligent Control LED — Datasheet
Addressable RGB LED; source for the 2.7 V minimum VIH that decides whether a 3.3 V MCU can drive it directly.
- Writing CSUBs for MMBasic on the PicoMite — Guide
- Writing Games in PicoMite MMBasic — Developer Guide
- Wyle Scientific Instruction Manual (1964)
The 20-page operating manual for the Wyle WS-01/WS-02 Scientific: registers, functions, and the optional PC-01 punched-card reader.
- Xometry's Firearm Policy (last updated 9 June 2022)
Xometry refuses look-alike weapons that are 'fully solid or cannot function by design'; bears on outsourcing any part of the build.
- Xtrusion Designs XTR3 BedRack Assembly Instructions (end-joint version, Ver. 1.1)
The maker's 19-page assembly sequence for the XTR3 bed rack: end joints, corner brackets, side braces and bed-rail brackets, with fastener torques. Generic across truck models. Cited by Bed Rack and Awning vol 3.
- Yamaha CP-80 Electric Grand Piano — Block Diagram
- Yamaha CP-80 Electric Grand Piano — Overall Schematics
- Yamaha CP-80 Electric Grand Piano — Schematics
- Yamaha V9938 MSX-Video — Technical Data Book (August 1985)
Light-pen mode: status S#1 FL/LPS and coordinates in S#3–S#6.
- YEW Series 3300 Analog Computer
Product brochure for the Yokogawa Electric Works (YEW) Series 3300 family of all-solid-state analog computers, covering models 3301 through 3306 with 10 to 72 operational amplifiers in a modular building-block architecture. Describes the 'High Speed Repetitive Computation / Low Speed Conversion' approach unique to YEW, computing-element accuracy of 0.1%, and a full range of linear and non-linear computing elements including multipliers, diode function generators, and comparators. Auxiliary devices such as the waveform translator for X-Y recorder, cathode-ray oscilloscope, digital voltmeter, delay device, and logic assembly units are also described.
- Your CURTA Calculator
The Curta operating instructions for Models I and II: handling, the four operations, and care. This is a retyped edition of Contina's printed manual, transcribed by Rick Furr in 1997 and reformatted as a PDF by Daniel Ford in 2005, so its page layout is not the original's.
- Your Strowger Automatic Equipment is tested (advertisement)
One-page AE advertisement on factory testing of Strowger equipment.
- ZDv 3/13 Das Gewehr G3 (Bundeswehr, 1978; amended 1999)
The Bundeswehr's central service regulation for the G3 rifle, issued in Bonn on 13 December 1978 and current to amendment 38 of 8 January 1999: description, handling, stripping, care and the illustrations. The HK PSG1 dive translates its mechanism, stripping and maintenance passages for the G3 family.
- Zeichnungssatz DO80 Analogrechner
A nine-page drawing set (Zeichnungssatz) for the Dornier DO80 Analogrechner, published by Dornier-System GmbH and Dornier AG, Friedrichshafen. The set comprises a master drawing index, sub-assembly parts lists, a photographic assembly overview, two-page assembly hierarchy block diagrams (covering housing, power supplies, control unit, computing elements, logic elements, and peripherals), three overview schematics (external connection leads, manual switches with relays, and the T/10 timer divider circuit), and a special manufacturing tools list. Documents are dated May 1973 through July 1975.
- Zilog eZ80 CPU User Manual (UM0077)
Zilog's manual for the eZ80 processor core used in the TI-84 Plus CE: architecture, Z80 and ADL memory modes, registers and instruction set.
- Zonhen ZHO-0420S-05A4.5 DC Solenoid — Specification (rev B)
A real Chinese hobby-solenoid specification (bilingual): ±5 % resistance, duty cycle, temperature rise, life.
- Zur numerischen Lösung von Dreikörnerproblemen des eingeschränkten Dreikörnerproblem
A German-language Telefunken application note presenting the analog computer solution of the restricted three-body problem (Earth–Moon system). The authors derive scaled machine equations from the equations of motion, select machine coefficients and time-scale factors, and provide a complete potentiometer list, variable (integrator) initial-condition list, and function-generator setting table for implementing the simulation on a Telefunken analog computer.
- Zur numerischen Lösung von Randwertaufgaben des eingeschränkten Dreikörperproblems
A two-page offprint (Sonderdruck) from Luftfahrttechnik Raumfahrttechnik (Vol. 14, 1968, pp. 220–221) presenting a numerical method for solving boundary value problems in the restricted three-body problem (Earth–Moon–spacecraft). The authors use the AEG-Telefunken Rechenanlage BA 741 analog computer to compute minimum-flight-time trajectories for an infinitesimal body (spacecraft) between two circular orbits in the rotating coordinate frame. Two distinct trajectory solutions are found and illustrated graphically.
- Zur Steuerung von Analogrechenschaltungen
A 1966 German academic article from the Institut für Angewandte Mathematik at Technische Hochschule München, presenting switching-control methods for sequencing analog computer programs. The authors (Heinhold and Kulisch) describe how a matrix-based digital control unit can manage the compute/halt/initial-condition phase sequence of analog integrators, including branching on comparator outputs for iterative convergence and multi-segment computations. Published in Elektronische Rechenanlagen, Vol. 8, No. 5, pp. 231–235, it anticipates the digital-control architectures of hybrid computers.
- Zweistrahloszillograph OMS 811 (Abschnitt 10)
Section 10 of a larger Telefunken analog computer system manual covering the OMS 811 dual-beam oscilloscope (Zweistrahloszillograph). Describes the instrument's purpose (display of analog computer output voltages up to 100 V), mechanical construction as a 19-inch rack slide-in unit, plug-in component population (amplifier units A-SV1A, switch units SP2A, sawtooth unit A-KM1, DN13-14 dual-beam CRT), electrical circuit design including power supply, high-voltage generation, input amplifiers, electronic channel switch, and maintenance/repair guidance.
- µKENBAK-1 v2.5 Assembly Booklet
Parts list and step-by-step assembly of the µKENBAK-1 v2.5 replica kit.
- µKENBAK-1 v2.5 Operation Instructions
Operating the µKENBAK-1 replica: front panel, programs and extra features.
- 小銃取扱 — JMSDF Sasebo Training Unit Diary Sheet, 4 December 2023
A JMSDF Sasebo Training Unit diary sheet on recruits' rifle-handling training with the Type 64. The Type 64 dive quotes it on how the rifles are guarded even during breaks.
- 小銃取扱 — JMSDF Sasebo Training Unit Diary Sheet, 5 July 2024
A JMSDF Sasebo Training Unit diary sheet on rifle-handling training. The Type 64 dive translates its statement that the Type 64 is the first rifle a member of the Maritime Self-Defense Force handles, used at ceremonies and in regular live-fire training.
- 装甲車両・火器及び弾薬の開発・調達について — MOD Briefing on Armoured Vehicle, Weapon and Ammunition Development and Procurement (2011)
A Ministry of Defense briefing of February 2011 on developing and buying armoured vehicles, weapons and ammunition; slide 4-5 tabulates the production and development history of self-propelled guns and small arms, with contract quantities to FY2009. The Type 64 dive cites it for the rifle's production.
- 試作品の概要 新小銃てき弾 — MOD Policy-Evaluation Sheet on the New Rifle Grenade Prototype (FY2005)
An annex to the Ministry of Defense's fiscal-2005 policy evaluation summarising the prototype new rifle grenade (the later Type 06) fired from service rifles. Cited by the Type 64 dive. Image-only; no text layer.
- 防衛大学校達第19号 — National Defense Academy Directive No. 19 on the Storage and Handling of Weapons (1992, as amended to 2020)
The National Defense Academy's directive of 31 August 1992 (as amended to 21 October 2020) on keeping and handling weapons, with the maintenance-echelon table (別表第1). The Type 64 dive translates it for what is public about the rifle's upkeep.
- 防衛装備移転三原則 — Three Principles on Transfer of Defense Equipment and Technology (2014)
The National Security Council and Cabinet decision of 1 April 2014 setting Japan's rules for exporting defence equipment. The Type 64 dive translates it to explain why no Type 64 has reached a private owner abroad.
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