The Sinclair Cambridge series of calculators was introduced in Summer 1973, and was the second calculator from Sinclair Radionics after the Executive was released in 1972. On release the Executive was the world's slimmest calculator, measuring a third of the size of other calculators available at the time. The Sinclair Cambridge was another small-sized range of calculators, and truly pocket-sized.

There was a number of different models in the Cambridge range. This example in our collection is the Memory model, and is believed to be the third variation out of three known variations which dates from around 1976. It is a four-function calculator with additional % and memory features. It featured the Mostek MK-50321 integrated circuit.

The Sinclair Cambridge Memory Types 2 and 3 differed from the Type 1 as they included a % key. The Type 3 also differed in that it had 'M' and 'C/CE' keys, and it was powered by a PPP3 battery compared to the 4 AAAs in the Type 1 and two AAAs in the Type 2. Due to the PPP3 battery, the Type 3 was one of the bulging "pregnant" models. It had a red plastic case with white keys, and an eight-digit Bowmar LED display.

This calculator was very kindly donated by Francis Hookham.

Manufacturer: Sinclair
Date: 1975

This exhibit has a reference ID of CH30323. Please quote this reference ID in any communication with the Centre for Computing History.

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