The Sinclair Executive calculator was the world's first slimline pocket calculator. It was released in 1972 and cost £79.95 +VAT. It was one third the size of any of its competitors in 1972 and cost half as much. Its small size was achieved by reducing the power input demanded by the TMS1802 chip that was used in the calculator by pulsing the current to the IC, reducing the power consumption by a factor of more than 10. The calculator was capable of addition, subtraction, division and multiplication, and was able to store a constant.

The Sinclair Executive won a Design Council Award for Electronics in 1973.

There are two known versions of casing for the Sinclair Executive with different keyboard markings. This example in our collection is Type 2 which has a separate = button, and has a K (constant) button, rather than the two-way switch on the Type 1 version. The two-way switch is used on this model for low/high brightness. There is also no decimal point switch on the right side of the calculator as there was on the Type 1, and the Type 2 is constantly set to floating point. The type 2 also had a GIM (General Instrument Microelectronics) C550 chip rather than the TMS1802 or TMS1803 found in the Type 1s.

Manufacturer: Sinclair Radionics
Date: 1972

This exhibit has a reference ID of CH70698. Please quote this reference ID in any communication with the Centre for Computing History.

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