Home > Hand-held Calculators

Check Tronic & Corvus CheckMaster

Check Tronic

Check Tronic

Display is 8 digits, red LED.

4-function.

A standard 4-function calculator incorporated in a wallet for balancing a bank cheque (check) account.
Unusually for this early date, the balance is stored even when the calculator is switched off, and can be recalled when switched on again. This is achieved by maintaining power to at least the memory.

9v (PP3 battery).

About 1975.

Manufacturing company not known (has logo which may be "AD").
If you have more information about this model please get in touch with us.

Corvus CheckMaster

Corvus CheckMaster

Display is 6 digits, red LED.

2-function.

This is a very basic calculator in a folding case for balancing a bank cheque (check) account. The display has a fixed decimal point for currency calculations, there is no decimal point key, and the only functions that provided are "Deposit" (add) and "Check" (subtract).
Like the Check Tronic above, the balance is stored even when the calculator is switched off, and can be recalled when next switched on. Again this is achieved by maintaining power to at least the memory.

9v (6x AAA batteries).

This example was purchased in July 1975.

Made by Corvus Corporation, of Dallas, Texas.

These calculators have the unusual feature, for this early date, of storing a number when the calculator is switched off. This is achieved by maintaining power to, at least, the memory and requires the very low power consumption possible using C-MOS (Complementary Metal Oxide Semiconductor) integrated circuits. However, if the batteries are removed the number is lost.

The Corvus CheckMaster is probably the least capable electronic calculator ever marketed, since it is only capable of addition and subtraction, though this is all that is required for its design purpose.

Vintage Calculators

© Text & photographs copyright Nigel Tout  2000-2007 except where noted otherwise.