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Sharp Compet 31 (CS-31A) Desktop Calculator

Sharp Compet 31 (CS-31A)
Image Courtesy Takaharu Yoshida

The Compet 31 (Model CS-31A) was a remake of the earlier Compet 30 (CS-30A) utilizing 28 small-scale bipolar integrated circuits to replace portions of the discrete transistorized logic used in the arithmetic unit of the Compet 30.
The Compet 31 was Sharp's first calculator to utilize integrated circuit technology. This calculator marked the beginning of a rapid transition away from discrete transistorized logic to more reliance on integrated circuit technology to shrink the size, increase the reliability, and reduce power consumption of Sharp's calculators.
While the first machine to use integrated circuits, Sharp did not heavily publicise this machine. Sharp actually gives credit to the Compet 32 as their first machine to utilize ICs, in spite of the fact that the Compet 32 actually uses fewer ICs than the Compet 31. It isn't historically clear why this occurred, but it could be that there were problems with the Compet 31 that led to to a very small production run, making the machine historically significant, but not significant from a market standpoint.

Sharp Compet 31 (CS-31A) Specifications

Manufacturer: Hayakawa Electric Co., Ltd. (Sharp)
Model Number: CS-31A (Compet 31)
Manufactured In: Japan
Date of Introduction: April, 1967
Display Technology: Nixie Tube, 14 Digits
Logic Technology: Small-Scale IC(28) and Diode(1549)-Transistor(553) Logic
Digits of Capacity: 14
Decimal Modes: Fixed via keyboard pushbuttons
Math Functions: Four Function
Memories: One memory register
Size: 17 1/4" wide, 18 3/4" deep, 8 1/2" high
Performance (Manufacturer Claimed): Addition/Subtraction: 15ms
Multiplication: 150ms
Division: 190ms

Copyright ©1997-2011, Rick Bensene.