Texas Instruments SR-40 Handheld Electronic Calculator

Texas Instruments SR-40 Handheld Electronic Calculator

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Usage conditions apply
This scientific handheld electronic calculator has a black plastic case with an array of forty small rectangular plastic keys. The ten digit keys, decimal point key, and change sign key are white. The total key and the four arithmetic function keys are gold. The brown keys include keys for reciprocals, squares, square roots, off, on/clear, inverse functions, sines, cosines, tangents, degrees, constant, enter exponent, common logarithms, natural logarithms, powers, pi, percentage, left parenthesis, and right parenthesis. The remaining brown keys are storage, recall, summation, and exchange.
Text above the keys reads: SR-40. Text behind this reads: TEXAS INSTRUMENTS. Behind the keyboard is an LED display that shows eight-digit positive and negative numbers and two-digit positive and negative exponents.
The calculator has a jack for a recharger/adapter along the right edge.Text on the back reads in part: TEXAS INSTRUMENTS (/) electronic calculator. It also gives the serial number 709159 and a date mark: LTA1277. It also reads: ASSEMBLED IN USA. Below these marks is a compartment for a TI battery pack BP-7. According to the instructions, the batteries in the battery pack could be recharged using an AC adapter/charger AC9131.
There are no screws for disassembling the calculator.
The calculator comes in a black plastic, cloth-lined, zippered carrying case with belt loop. Also in the case is a manual with the title Texas Instruments electronic slide-rule calculator SR-40 Owner’s Manual. The name Guy E. Richardson has been blacked out.
[Advertisement], Los Angeles Times, October 30, 1976, p. C2. Gives price of $33.95, advertises calculator as successor to the SR-50A.
[Advertisement], Chicago Tribune, April 6, 1977, p. A11. Gives price of $39.95.
[Advertisement], Los Angeles Times, September 7, 1977, p. C16. Sale price $25.99, regular price $29.95.
[Advertisement], Boston Globe, January 15, 1978, p. 89. Gives price of $19.99.
Currently not on view
Object Name
electronic calculator
Other Terms
electronic calculator; Handheld
date made
Texas Instruments
Physical Description
plastic (case; keys; carrying case material)
metal (circuitry material)
paper (manual material)
overall: 1 1/4 in x 3 in x 5 3/4 in; 3.175 cm x 7.62 cm x 14.605 cm
ID Number
catalog number
accession number
Credit Line
Gift of John B. Priser
See more items in
Medicine and Science: Computers
Computers & Business Machines
Handheld Electronic Calculators
Data Source
National Museum of American History
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The TI battery pack, BP-7, can be replaced with a standard 9V dry cell. I've had one at my desk for over 28 years (since 1990).

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