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.

The Sinclair Cambridge Programmable is one the later model of the Cambridge series, which was released in 1977. It is a scientific calculator with memory, algebraic logic, and brackets function. The calculator has a 36-step programme memory, and features conditional and unconditional branch instructions. It also has step facility, allowing the user to step through the program to check it has been entered correctly. The calculator was supplied with 12 sample programs. A 294-program library, which was divided into four books was also available to purchase for £4.95 as a set, or for £1.95 each.

The calculator has an eight-digit LED display, and is powered by one PP3 battery, making it one of the bulging "pregnant" models. It features the National Semiconductor MM5799EHY/N and DS7784N integrated circuits.

The Sinclair Cambridge Programmable Calculator was also sold in the U.S as the Radio Shack EC-4001.

The calculator cost £17.23 including VAT in May 1977, which was much cheaper than any other programmable calculators at the time.

This example in our collection is complete with its original packaging, power supply, and documentation.

Manufacturer: Sinclair
Date: 1977

This exhibit has a reference ID of CH39538. Please quote this reference ID in any communication with the Centre for Computing History.

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