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 Scientific model, which was launched in Spring 1976. It was the first time a Sinclair scientific calculator offered algebraic logic, a choice between scientific or normal notation, a choice between degrees or radians operation, and a full five-function memory. It featured the General Instrument CF596 as its main integrated circuit, which Sinclair had previously used in the Sinclair Oxford 300 scientific calculator. It had an eight-digit LED screen in scientific format with a 5-digit mantissa and a 2-digit exponent. It was powered by two AA batteries.

A major factor in the Cambridge's success was its low price; the Cambridge Scientific cost £16.95 +VAT at its launch.

The use of cheap components was an important contributor to the unit's cost. 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.

Our Sinclair Cambridge Scientific, together with the original hard case, was very kindly donated by Julian Bryant.

Manufacturer: Sinclair Radionics
Date: 1976

This exhibit has a reference ID of CH21989. Please quote this reference ID in any communication with the Centre for Computing History.

Click on the Image(s) For Detail