Slide Charts:

RCA Pindex - 1936 Double sided. Gives pin-outs and tube data for RCA Radiotron vacuum tubes on both sides with instructions on the back. Printed by Whitehead Hoag. Size: 6½" X 3" Larger Photo

Ohmite Ohms Law Calculator 1941, Double sided. On one side it has scales to compute ohms law along with volts and wattage required up to 1000 ohms. The second side covers the 1000 ohm to 10 megohm ranges. Instructions are printed on each side. Size: 9¼" X 4+" Larger Photo

Ohmite Parallel Resistance Calculator 1949, Double sided. On one side it has several scales to compute Parallel Resistance. It also has a standard slide rule. The other side is an Ohms Law Calculator. Instructions are on slide. I have two versions of this © 1949 slide card. A cardboard version which has a price of 25 cents and a plastic covered version with a printed price of $2.50. Cardboard version once owned by Elmer Taylor (he printed his name on the slide). Size: 8¾" X 3" Larger Photo (cardboard version)

Ohmite Parallel Resistance Calculator 1970, Double sided. On one side it has several scales to compute Parallel Resistance. It also has a standard slide rule. The other side is an Ohms Law Calculator. Both faces have a clear vinyl cover. Instructions are on slide. Size: 9" X 3" Larger Photo

Ohmite Capacitor Calculator 1960, Double sided. On one side it has scales to compute frequency with effictive series capacitance, reactance and more. The second side has a range chart with formulas and a standard slide rule. Instructions are printed on the face. Size: 7¼" X 2¾" Larger Photo

Allied Radio Resistance Capacitance Caculator Double sided and has different ranges on each side. Size: 12½" X 3½" Larger Photo Paper Cover Instructions (Adobe PDF File)

Allied Radio Coil Winding Caculator Double sided. On one side it has several scales to compute coil Inductance and uses coil length, diameter, wire size, turns per inch, etc. The other side calculates R-F Resonance and Ciol Winding. It has scales for frequency/wavelength and Inductance/Capacitance. Size: 10" X 5" Larger Photo Paper Cover Instructions (Adobe PDF File)

"The Ballantine Rule" 1953 This slide chart by Ballantine Laboratories has a DB - Ratio conversion scale on one side and a Volts - DB power level converter on the other. The Ballantine Voltmeter Scale Reference card with it has a scale to compare voltage ratio and decibels. Cards produced by the Perry Graph Corp. Slide Size: 8½" X 3" Card Size: 3¾" X 2¼" Larger Photo Instructions (Adobe PDF File)

Amphenol RF Connector and Cable Selector - 1954 This is a spiral bound, double slide card. There are two cards that are attached like a spiral notebook. One card is a slide chart for selecting the proper Amphenol RF connector and cable, the second card provides a cross reference to RF cable, and cable assemblies. Card produced by the Perry Graph Corp. Size: 9½" X 4¼" (closed) Larger Photo Photo of second side

GE Range and Signal Strength Calculator - 1952 This General Electric slide chart is double sided with a plastic cover over a cardboard slide card. Front has slide chart for antenna height to key number and reverse has slide chart for megacycles and signal in microvolts along with key number calculated on front. Card produced by the Perry Graph Corp. Size: 6½" X 2" Larger Photo Photo of storage sleeve

Motorola Zener Diode Calculator 1959 This Motorola slide chart calculates volts, amperes, and wattage of Zener Diodes. Back has a chart for selecting the proper Motorola Zener Diode by nominal/tolerance voltages. Instructions are on paper sleeve. Card was produced by the Perry Graph Corp. Size: 12" X 4¾" Larger Photo Instructions (Adobe PDF File)

Shure Reactance Slide Rules 1942 Here are two slide cards from Sure Brothers Inc. These double sided slide cards were used to calculate the resonant frequency equation for microphones. On one side they have scales to calculate capacity, inductance, and frequency. The other side has scales for capacitive reactance and inductive reactance. These cards were produced for Shure by the Perry Graph Corp. Approx. Size: 8½" X 3½" Front Reverse Instructions (Adobe PDF File)

Fenwal Thermistor Computer 1966 Front slide chart calculates resistance at various tempaturer points. Has scales for current, voltage, and resistance ranges. Reverse side has seven scales bases on resistance teperature curve. Produced by the Perry Graph Corp. Approx. Size: 6½" X 9" Front Reverse

Wheel Charts:

Free Reference Point System Disk During the 1930's, Supreme Instruments supplied a Free Reference Point System Disk with many of their vacuum tube testers and radio analyzers. This two sided disk allowed easy identification of which tube pin jacks on the tester to use by rotating the inner wheel to the tube number under test Size: 5" Larger Photo Side A Larger Photo Side B

De Forest OHM's Law Wheel Chart - 1926 Single sided. More like heavy paper than cardboard. This is the oldest wheel chart in my collection so far. It was given out by De Forest's Training Schools . The wheel shows the OHMs Law formula by setting the circle over the value you are trying to calculate. I'm not sure of its purpose since the three formulas are printed next to the wheel. Size: 6" X 2¾" Larger Photo

IRC "Resist-O-Guide" This 1946 card from International Resistance Company (better known as IRC) shows the resistance color markings for standard carbon resisters. It is rectangular and has three wheels to spin for finding color and resistance value. The back shows a chart and has a diagram comparing the "New" standard color code to the old color code used on older "Dog Bone" resistors (see the older IRC chart below). Size: 4.5" X 2.125" Larger Photo

Ohmite "Little Devil" This small coder from Ohmite shows the resistance color markings for standard carbon resisters. It is rectangular and has three wheels to spin for finding color and resistance value. The back shows a chart with a diagram showing the meaning of the four standard color bands. Size: 4¾" X 2" Larger Photo

National OHM's Law and Battery Life Calculator - 1959 This wheel calculator has a dial on one side to compute OHM'S Law (resistance, voltage, and amps) and a battery life calculator on the other. This chart was produced by the Perrygraf Slide Chart Corp. Size: 5" across X 6" high. Larger Photo

Sprague Capacitor Indicator - 1949 This small plastic 6 wheel cap indicator from Sprague shows the capacitance color markings for tubular capacitors. It is rectangular and has six wheels to spin for finding capacitance value. The back has a chart for converting MFD to MMFD. Size: 5" X 1½" Larger Photo

Daven - Thomas A. Edison Industries "Resisto-Dial" (No date or manufacturer) This wheel calculates confidence level (Failure Rate) of several types of resistors. The reverse calculates deviation by tempeture and has charts for wattage derating. Size: 7½" Larger Photo Front Larger Photo Front

Grundig Tape Head Calculator Used to set up "overdubbing" using the SYN function that allowed playback of a track, while recording another, and mixing the two together. Size: 7½" Larger Photo Side A Larger Photo Side B

Radio Shack Resistor/Capacitor Color Code Calc. This small coder from Radio Shack shows resistor and capactor color markings on one side and the inductor color code on the other. Size: 4¼" X 2¼" Larger Photo

TV Quick-Check Trouble Finder This two sided wheel chart from 1956 helps troubleshoot TV problems. Turn the wheel till your picture problem appears in the top window and read the tubes you need to test in the bottom window. Size: 7½" Larger Photo - Front Larger Photo - Rear

This is a large wheel chart that calculates Proportional Scale. Although it does not directly relate to antique radios or electronics, it can be used in my wood shop. It comes in handy when I need to reduce something by a percentage and want the results in inch measurements. Produced by the C-Thru Ruler Company Size: 8¼ Larger Photo

This large wheel chart (over 10" in diameter) calculates postage and lists addresses world wide for Ham Radio QSL card mailing. Both sides show Continent, Zone, and Country. Published by Ham Radio Magazine circa 1976 - Size: 10+" Larger Photo

This small metal wheel calendar calculates dates by year and day of week from 1965-1992. It has the Bell Telephone logo on the back and was probably given out as a promotion. Manufactured by Anderson and Sons, Westfield Mass. Size: 1¼" x 1¼" Larger Photo

General Electric Radar Range Computer This wheel chart has 5 ranges on the front for Pulse Repetion Rate, Transmitter Power, Wave Length, Pulese Duration, and Target Size. There are 4 additional scales on the back for Wave Length, Frequency, angle, and Gain. Published by the GE Heavy Military Electronic Equipment Department, Syracuse NY, 1955. This chart was printed by the Perrygraf Slide Chart Corp. The wheel chart stores in pocket inside the instruction book. I grew up in Syracuse and remember driving by the GE plant in the 1960s and seeing all the types of radar arrays outside the plant that are listed on the back page of instruction book below. Wheel Size: 8" Larger Photo - Front Larger Photo - Back Instruction Book (Adobe PDF File)

The Merit Output Transformer Selector allows you to select needed specifications on the top of the wheel. Merit part number and type are then indicated in the window. This wheel is two sided and was printed by the Perrygraf Slide Chart Corp. Size: 6.5" Larger Photo

This GE Lighting Systems digitaldiscwheelTM and the one below are a unique promotional and distribution idea combining Wheel Charts with new digital technology. This type of wheel can be configured with information on the face of the disk like a wheel chart and opens to reveal it's a recordable DVD that can contain digital files such as catalogs, price sheets, or any other type of file. This one contains a GE Lighting time line on its face. Manufactured by Flexigroup, New York. Size: 4 7/8;" x 5". Larger Photo More information and working samples are available on-line at digitaldiscwheels.com

This is a Star Wheel digitaldiscwheelTM. It provides a star chart by date & time and like the digitaldiscwheelTM above can also be loaded with digital files for distribution. Manufactured by Flexigroup, New York. Size: 4 7/8;" x 5". Larger Photo More information and a working sample of this wheel are available on-line at digitaldiscwheels.com

Reference Charts:

IRC Resistor Color Code This chart from International Resistance Company (better known as IRC) shows the resistance color markings for their early "Dog Bone" resistors. The card is one sided. No date is marked on the chart but these type of resistors were used in radio construction from the 1920s through the mid 1930s. Size: 3¼" X 6¾" Larger Photo

This Cornell-Dubilier chart shows the six and three dot RMA Standards color code for their mica capacitors on one side and the Joint Army - Navy Standard color code on the other. Size: 2¾" X 4¾" Larger Photo

This Sangamo capacitor chart shows the three and six dot RMA Standards and proposed color code for their mica capacitors. The card is folded with a cover and three charts. No date. Size: 3" X 10" unfolded Photo

Miscellaneous Items:

CCW Metric Converter-Pencil Cup 1970s This unique metric converter doubles as a pencil cup. It was also available in black with white lettering. Has two movable rings. There was also a slide rule version. Cup was made in Denmark by the CCW Slide Rule Co. Size: 3.75" X 2.75" Photo

Lightning Calculator 1910-1920 This mechinical calculator is from the early 1900s. It was manufactured by the Lightning Calculator Co. of Grand Rapids Michigan. There was a much later version manufactured by Lightning Adding Machine Co., Inc. of Los Angeles CA. Size: 13.25" X 3.75" X 2.25" Photo

Slide Rules Click on the photo for a look at a couple interesting slide rules. The one pictured top left is a 6" rule and probably a promotion given out by Solid State Electronics of Illinois. It comes on a nifty little leather pocket protector. #601-1 made by Diwa in Denmark. The second slide rule is my favorite to actually use. It's made by Nestler of Germany, model Nr. 0291. It's works very smooth. Wish I had this one in High School. Larger Photo

This is a part of my collection of Slide Charts and Wheel Charts. More relating to vintage radio and electronics will be added here as I get time. Thanks for visiting.

Links to Companies that produce
Slide Charts and Wheel Charts:

• Alcott Calculator Company
• American Slide Chart/Perrygraf
• C-Thru Ruler Company
• Datalizer Slide Charts Inc.
• Flexigroup
• IWA Incorporated

Steve's Vintage and Antique Test Equipment Collection


Radios/Victrolas  Schematics  Parts 
Coca-Cola Collectables  Miscellaneous  Purchase
Contact  Collection  Radio Ads  Links  Home Page


Copyright © 1995-2012 Steve Johnson, Auburn NY, All rights reserved.