Texas Instruments Exactra 20 Handheld Electronic Calculator (TI-20)

Description
This handheld electronic calculator is one of a series of “exactra” calculators introduced by Texas Instruments in the spring of 1974. It has an off-white plastic case, an orange keyboard, and eighteen nearly square plastic keys. These include ten digit keys, a clear entry key, a clear key, a decimal point key, four arithmetic function keys, and a constant key. An on/off switch and a $/F (for dollars / floating point) key are on the left in the top row of keys. A mark at the top of the keyboard reads: exactra 20. Behind this is a six-digit red LED display.
The calculator has no provision for a charger/adapter. A battery compartment at the top of the back would hold three AA alkaline or carbon-zinc batteries. A mark molded into the plastic on the back reads in part: TI-20 ELECTRONIC CALCULATOR (/) MADE BY TEXAS INSTRUMENTS INCORPORATED. It also gives instructions. Toward the bottom of the back is the stamp: 274. A tag below this reads: SERIAL NUMBER 2000036485.
Unscrewing two screws on the back allow one to remove it. The calculator has two chips. The larger one is marked: TMS 0135 NC (/) C7422. This is a TMS0135 chip. The smaller one is marked: M7419 (/) SN27882.
References:
[Advertisement], New York Times, May 2, 1974, p. 18. Exactra 20 selling for $39.99.
[Advertisement], Chicago Tribune, Dec 15, 1974, p. T17. Texas Instruments Exactra 20 selling for $19.88.
[Advertisement], New York Times, September 10, 1975, p. 6. Exactra 20 calculator, regularly $29.99, now $14.99.
Online Datamath Museum, accessed June 2, 2015.
Location
Currently not on view
Object Name
electronic calculator
date made
1974
maker
Texas Instruments
Physical Description
plastic (overall material)
metal (circuitry material)
paper (sticker material)
Measurements
overall: 1 3/8 in x 2 5/8 in x 5 in; 3.4925 cm x 6.6675 cm x 12.7 cm
ID Number
1986.0988.323
catalog number
1986.0988.323
accession number
1986.0988
subject
Computers & Business Machines
Handheld Electronic Calculators
See more items in
Medicine and Science: Computers
Handheld Electronic Calculators
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of John B. Priser
Additional Media

Visitor Comments

Add a comment about this object

**Please read before submitting the form**

Have a comment or question about this object to share with the community? Please use the form below. Selected comments will appear on this page and may receive a museum response (but we can't promise). Please note that we generally cannot answer questions about the history, rarity, or value of your personal artifacts.

Have a question about anything else, or would you prefer a personal response? Please visit our FAQ or contact page.

Personal information will not be shared or result in unsolicited e-mail. See our privacy policy.

Image CAPTCHA
Enter the characters shown in the image.