Texas Instruments SR-16 II Handheld Electronic Calculator

This is an example of a scientific calculator introduced by Texas Instruments in 1975 that offered many of the capabilities of the SR-16 calculator at a lower cost. The handheld electronic calculator has a black plastic case with an array of thirty-one small rectangular plastic keys. In addition to ten digit keys, a decimal point key, a change sign key, a total key, four arithmetic function keys, a clear display key, and a clear key, the calculator has twelve further function keys. These are for powers, reciprocals, square roots, squares, logs to the base 10, storage, recall, summation, exponents, natural logarithms, entering exponents, and pi. The meaning of the keys is indicated on the keyboard, not on the keys themselves. Text on the keyboard, above the keys and to the right, reads: SR-16 II. Behind the keyboard is a twelve-digit LED display that shows eight-digit positive and negative numbers and two-digit positive and negative exponents. A mark below the display reads: TEXAS INSTRUMENTS. The on/off switch is right and slightly above this mark.

The calculator has a jack for a recharger/adapter along the back edge. A sticker on the back gives instructions. It also gives the serial number SR-16 II 180524. It also reads: ASSEMBLED IN USA. Above the sticker is a compartment for three batteries. A mark below the sticker reads: LTA4375.

Unscrewing four screws on the back reveals the workings of the calculator. It has a total of three chips. The largest of these is marked TMS1016NL (/) KAΔ7543. This is a TMS1016 chip, manufactured in late 1975.

The calculator comes in a dark brown plastic zippered case with belt loop.

References:

[Advertisement], New York Times, May 5, 1976, p. 10. Gives a sale price of $29.

[Advertisement], Chicago Tribune, October 19, 1975, p. A7. Gives price of $44.95.

Guy Ball and Bruce Flamm, The Complete Collector’s Guide to Pocket Calculators, Tustin, CA: Wilson/Barnett, 1997, p. 153.

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