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Sinclair Cambridge Programmable

Sinclair Cambridge Programmable

The Sinclair Cambridge Programmable is a programmable calculator with 8 digits precision and algebraic logic. It has 51 functions, 19 keys, and an LED (light-emitting diode) display, typical of calculators of this era. The power source is PP3 9V.

This fascinating and very early programmable calculator came with a huge set of four manuals containing programs to solve various mathematical financial and engineering problems.

It was obviously quite a challenge to create a programmable calculator with so few keys. Power was also a problem - a higher voltage than anticipated was needed to achieve sufficient speed, and so a 9V battery was used to replace the AAA batteries used in other calculators in the Cambridge series. Unfortunately the only way to accommodate this was with a special battery cover with a bulge to accomodate the larger battery. As a result the calculator does not sit squarely on the desk but topples.​

A sample of this calculator is held in the collection.

Facts at a glance:

Display typeLED
Power SourcePP3 9V
Original price$35
Est. current value$75
Year introduced1974
Year discontinued1978


If you have a Sinclair Cambridge Programmable that is no longer working, you can first try replacing the PP3 9V battery. If that doesn't solve the problem, then you can consider replacing the calculator with a modern equivalent.

We suggest the following current model as a replacement:

See other calculators by Sinclair