Cardboard Engineering & Science Slide Rule Calculators
The Original Mobile Apps™

ARRL Lightning Calculator- Type B Modified

The American Radio Relay League (ARRL) sold a variety of these "Lightning Calculator" slide rules in the days before electronic calculators. This "Type B" version (copyright 1932, W.P. Koechel) calculates Ohm's Laws values for resistance, voltage, current, and power. As shown here, it indicates an alignment of 1 V, 1 A, and 1 Ω. The Lightning Calculators" were rather large at 8½" wide by 11" high. Being the size of a sheet of paper, it is surprising they did not come with holes for a 3-ring binder. There were six varieties of "Lightning Calculators," as shown in the 1939 QST magazine advertisement.
Thanks to Joe Birsa (N3TTE) for the donation - Added October 19, 2020

Shure Brothers Reactance Slide Rule

Thanks to Neil Blaho for the donation
(copyright 1957)  Added July 6, 2017

JFD Mfg. Co. Stroboscopic Disc

Thanks to Neil Blaho for the donation
(circa 1950s)  Added July 6, 2017

itron Reciprocal Calculator

Thanks to Neil Blaho for the donation
(copyright 1968)  Added July 6, 2017

Naval Surface Warfare Center: Electric Field Slide Rule

Thanks to Neil Blaho for the donation
(copyright 1991)

Honeywell: Signal Level Conversion Slide Rule Wheel

Thanks to Neil Blaho for the donation
(Annapolis, MD, was my childhood home town)

Flam & Russell: Radar Cross-Section Cardboard Slide Rule

Thanks to Neil Blaho for the donation
(copyright 1968)

muRata: Dial-a-Bead Selector Wheel

Thanks to Neil Blaho for the donation

HP: HP 9000 Series 200 Memory Configuration Wheel

Thanks to Joe Cahak for the donation

HP: HP 9000 Series 300 Memory Configuration Wheel

Thanks to Joe Cahak for the donation

AILTECH: Noise Slide Rule

Thanks to Joe Cahak for the donation
(copyright 1973)

Andrew: Heliax Slide Rule

Thanks to Joe Cahak for the donation

inmet: Gain Equalizer & Conversion Calculator

Thanks to Joe Cahak for the donation
(copyright 1999)

Miteq: Mixer Spur Analyzer Calculator

Thanks to Joe Cahak for the donation

Tektronix: Time Domain Reflectometer Slide Rule

Thanks to Joe Cahak for the donation
(copyright 1972)

Ohmart Corporation: Radiation Measurement Calculator 

Thanks to Joe Birsa (N3TTE) for the donation
(copyright 1991)

Daniel Industries, Inc.: Air-Gas Orifice Flow Calculator

Thanks to Joe Birsa (N3TTE) for the donation
(copyright 1977)

EM Laboratories: U.S. ↔ Metric Conversions

Thanks to Gary Steinhour for the donation
(copyright 1975)

FXR (now Microlab/FXR): Smith Chart Slide Rule

Smith Chart Side

Slide Rule Side
Thanks to Gary Steinhour for the donation)

Sage Wireline/Wirepac Calculator

Sage Wireline/Wirepac Calculator
(copyright 1992)
I have a spreadsheet available for the Wireline Calculator.

Andrew Microwave Antenna System Computer

Andrew Microwave Antenna System Computer
(copyright 1994)

Nuclear Bomb Effects Computer

Thanks to Ken H. for the photos of his Nuclear Bomb Effects Computer (likely the original 1957 version), produced by The Lovelace Foundation and EG&G. "This Nuclear Bomb Effects Computer has been compiled in cooperation with the Atomic Energy Commission, Division of Biology and Medicine, and Lovelace Foundation for Civil Effects Test Operations AEC-Biology And Medicine Contract AT(29-1)1242." Quickly and handily calculates Max. Fireball Radius, Height for Minimal Fallout, Apparent Crater Radius and Depth, and even Radiation Levels with 1st, 2nd, and 3rd degree burns! Who wouldn't have wanted one of these back in the 1960s while hunkering down in an underground bunker or beneath your school desk while thermonuclear ordinance was exploding overhead? Added April 11, 2022

Varian Power Amplifier Calculator

Thanks to Neil Blaho for the donation
(copyright 1991)  Added July 6, 2017

Tecom Industries Antenna Calculations Slide Rule

Thanks to Neil Blaho for the donation
(copyright 1976)  Added July 6, 2017

Scientific Atlanta Antenna Communications Systems Calculator

Thanks to Neil Blaho for the donation
(copyright 1977)  Added July 6, 2017

REA Magnet Wire Co. Heavy Formvar Magnet Wire Slide Chart

Thanks to Neil Blaho for the donation
(circa 1950s)  Added July 6, 2017

The Helipot Corporation Electrical Slide Rule

Thanks to Neil Blaho for the donation
(copyright 1951)  Added July 6, 2017

Scientific Atlanta: Antenna Calculator Slide Rule

Thanks to Neil Blaho for the donation
(copyright 1968)

Pacific Automation Products: Copper Wire Slide Rule

Thanks to Neil Blaho for the donation
(looks a little like the Starfleet Command logo)

Hughes Electron Dynamics Division: Millimeter Wave System Calculator

Thanks to Neil Blaho for the donation
(copyright 1975)

Instrument Specialties Company: Shielding Design Guide "sticky fingers" Slide Rule

Thanks to Neil Blaho for the donation
(copyright 1982)

MegaPhase: Watts & Voltage Conversion Slide Rule

Thanks to Joe Cahak for the donation
(copyright 2009)

HP: Reflectometer & Mismatch Error Limits Calculator

Thanks to Joe Cahak for the donation
(copyright 1976)

Amphenol RF Division: Smith Chart Slide Rule

Thanks to Joe Cahak for the donation

Concise: Chemical Element Slide Rule

Thanks to Joe Cahak for the donation
(copyright 1968)

Microwave Development Labs (MDL): Rigid Waveguide Data Calculator

Thanks to Joe Cahak for the donation
(copyright 1995)

Rogers Corporation: High Frequency Substrate Selector

Thanks to Joe Cahak for the donation
(copyright 2010)

Roos instruments: RF & Reactance Calculator

Thanks to Joe Cahak for the donation
(copyright 1995)

Control Components: Valve Sizing Calculator

Thanks to Joe Birsa (N3TTE) for the donation
(copyright 1986)

The Ballentine Rule: dB <--> Ratio Conversion | Volts <--> dB Power Level

Thanks to Gary Steinhour for the donation
(copyright 1953)

Tel-Instrument Electronics Corp.: AC Power Slide Rule

Thanks to Gary Steinhour for the donation
(copyright 1964)

M/A-COM: VSWR Calculator

(copyright 1983)

APN-85 Pressure Reduction Computer

I. Sea-Level Reduction (left), II. Altimeter Setting (right)
These were used by air traffic controllers back in the Stone Age This particular model was auctioned off when the Bedrock Airport closed.
Thanks to Don Hicks for the donation

GE Mobile Radio Range and Transmitter Power Calculator

GE Mobile Radio, Range and Transmitter Power Calculator
(copyright 1977)
Thanks to Alan Kealey for the donation!

Pickett N600 ES Log-Log Slide Rule

Pickett N600 ES Log-Log Slide Rule
(this is the same model that went to  the moon w/the Apollo astronauts)

Skala Wilcza 32 Wooden Slide Rule

Skala Wilcza 32 Wooden Slide Rule (Poland)
Thanks to Alan Kealey for the donation!

Cleveland Institute 515-T Slide Rule

Cleveland Institute 515-T Slide Rule (made by Pickett)
Send me an e-mail if you want a PDF file of a partial (10 pages) copy of the instruction manual.
[Buy the complete manual set here]

This advertisement appeared in the August 1967 edition of Electronics World magazine. The unique slide rule, leather case, and 4-course instruction booklet was "...deliberately underpriced at less than $25."

Cleveland Institute of Electronics

Cleveland Institute of Electronics Slide Rule Product Feature
January 1965 Popular Science

Texas Magnum Slide Rule

Texas Magnum, World's Longest Slide Rule
(352 feet long, 300 pounds)

Projection Slide Rule

Projection Slide Rule

K&E Model N4080-3 Log Log Duplex Trig

K&E Model N4080-3 Log Log Duplex Trig, S/N 467192, Copyright 1947 Slide Rule
(wooden frame & bar w/metal ends)

K&E Model 4081-3 Slide Rule

K&E Model 4081-3 Slide Rule, S/N 087105
(wooden frame & bar w/metal ends)

Sterling 684 White Plastic Slide Rule

Sterling 684 White Plastic Slide Rule
(I bought this for my first algebra class in 1976)

Pickett N1010-T Slide Rule

Pickett N1010-T Slide Rule
(found in my father-in-law's basement)

K&E Beginner's Slide Rule

K&E Beginner's Slide Rule, Model 4058C
(all-wood frame & bar)

Lawrence Slide Rule Instruction Book

Lawrence Slide Rule Instruction Book
(copyright 1952)

Other Interesting Slide Rule Configurations

Gong Se He Ying
Metalworking calculator for Iron materials

Slide Rule Wallpaper

Slide Rule Wallpaper
Click on the image to open it in a new window, then right-click on it and choose Set as Background

Soviet Slide Rule Watch

Soviet Slide Rule Watch