Texas Instruments TI-55 Handheld Electronic Calculator

This handheld scientific electronic calculator has a black plastic case and forty small rectangular plastic keys arranged in eight rows. In addition to ten digit keys, a decimal point key, and a change sign key (all off-white), the calculator has a total key and four arithmetic function keys (all gold). The remaining keys are brown. Pushing the “2nd” key allows keys to serve a “dual function,” which is denoted by text above the keys. The calculator provides a wide variety of statistical, trigonometric, hyperbolic, logarithmic and exponential functions, as well as conversions of units of measure. The calculator has limited programming capabilities.
A mark at the top of the keyboard reads: TI-55. Text behind the display reads: TEXAS INSTRUMENTS. Next to this is an on/off switch. Behind this is an LED display that shows eight positive or negative digits of the result as well as powers of ten from -99 to +99.
A jack for a power supply is along the right edge.
Text on the back of the calculator reads in part: TEXAS INSTRUMENTS (/) electronic calculator (/) SERIAL NO. (/) 99042531. It has the date mark: LTA1278. It also reads in part: ASSEMBLED IN USA. Below the marks is a compartment that holds a battery pack. Text on it reads: TEXAS INSTRUMENTS BATTERY PACK BP-5. There are no screws on the back of the case and the chips are not visible.
The calculator has a black zippered plastic case with a carrying loop.
An April 1978 newspaper advertisement described the TI-55 as a “new” calculator “with all the functions and features of the popular SR-51 II, plus a 32-step program memory.” It gave a list price of $59.95 and a sale price of $49.95. By September 1978, the SR-55 was advertised as a less expensive alternative to the TI-58 and TI-59. By 1982 TI had released the TI-55-II.
Compare 1986.0988.358 (an SR-51-II)
[Advertisement], Boston Globe, March 26, 1978, p. 83. Relatively detailed description. Gives price of $49.95.
[Advertisement], Los Angeles Times, April 8, 1978, p. C5.
[Advertisement], Washington Post, September 9, 1978, p. A15. Device selling for $34.93. The TI-58 costs $87.96, the TI-59 $219.44.
[Advertisement], Los Angeles Times, September 8, 1979, p. D7. Selling TI-55 as a “super slide rule” for $44.95.
[Advertisement], Chicago Tribune, May 11, 1980, p. W_C55. Selling TI-55 “advanced slide rule calculator” for $32.99, regularly $37.99.
[Advertisement], Los Angeles Times, March 25, 1981, p. 22. TI-55 selling for $29.95.
[Advertisement], Los Angeles Times, April 17, 1982, p. C3. TI-55-II selling for $44.95.
Currently not on view
date made
Texas Instruments
Physical Description
plastic (case; keys; carrying case material)
metal (circuitry; zipper material)
overall: 1 1/2 in x 2 3/4 in x 5 1/2 in; 3.81 cm x 6.985 cm x 13.97 cm
ID Number
catalog number
accession number
Credit Line
Gift of John B. Priser
See more items in
Medicine and Science: Computers
Handheld Electronic Calculators
Computers & Business Machines
Data Source
National Museum of American History, Kenneth E. Behring Center


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