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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) appears to have been a remake of the earlier Compet 30 Model CS-30B. From available information(of which there is not a lot), it is essentially identical to the CS-30B. Sharp claims that the Compet 31 (Model CS-31A) was their first electronic calculator to utilize small-scale bipolar integrated circuits to replace chunks of discrete transistorized logic. However, examples of the earlier Compet 30 Model CS-30B exist that have a small number of the same Mitsubishi-made ICs as used in the Compet 31 and later Compet 32.

Instances of both model of calculators do exist today, but at this writing, the Old Calculator Museum has not been able to get enough detailed information on either of these models to be able to make a determination as to what the differences are.

Whichever Sharp calculator truly holds the title of being their first electronic calculator to use ICs, it's very clear that the early use of small-scale bipolar integrated circuits led to a very rapid move by Sharp away from discrete transistor circuitry to more reliance on integrated circuit technology. Through the use of IC technology made in its homeland, Sharp gained a market advantage over other Japanese electronic calculator manufacturers, who had to rely more expensive integrated circuits from chipmakers in the United States. The use of ICs reduced the size, made the calculators easier to manufacture (reduced component count), increased reliability, and reduced power consumption -- all factors that contributed to Sharp's market leadership over competing Japanese calculator manufacturers at the time.

If you own either of these calculators, please press the EMail button at the top of the page, and send me an EMail about your calculator. Even if it isn't available for the Old Calculator Museum to acquire, information you can provide could be very helpful in answering the question as to which machine Sharp truly ended up using integrated circuits in first.


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 ©1997-2018, Rick Bensene.