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.

This example in our collection is the first model of the Cambridge series, which there are four known variations of. This is the first variation and is identified by its 'C' and 'K' keys. It is a four-function calculator. It has an eight-digit LED screen, and is powered by four AAA batteries. It features the General Instruments GI-C550 integrated circuit.

The calculator cost £29.95 plus VAT. It was also available as a kit, which cost £24.95 plus VAT.

Due to the cheap materials used in the calculator it suffered from a design flaw in that after a certain amount of use, it became impossible to turn off the calculator due to the oxidation of the tin-coated nickel connectors which were used rather than the gold-flashed nickel connectors generally used. This meant the user had to remove the battery to cut the power to the calculator.

Manufacturer: Sinclair Radionics
Date: July 1973

This exhibit has a reference ID of CH5044. Please quote this reference ID in any communication with the Centre for Computing History.

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