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Sinclair Radionic

Display is 8 digits, red LED.

4-function, %, square root.

9v (PP3 battery).

73 x 155 x 34 mm (2.9 x 6.1 x 1.3 ins).


Made in England.

This has the key layout of the Sinclair Oxford 150, but has the later, more rounded, design of the Oxford case coupled with the red LED display of the earlier Oxford design instead of the normal green fluorescent display of the later design.


Radionics Products Ltd., of Bristol, a member of the ESL Bristol group of companies, apparently bought the rights to the Radionics name and old Sinclair calculator stock/parts/dies around 1979.

In 1979 the British "National Enterprise Board" (the namesake of the Enterprise calcs) which had a large stake in Sinclair Radionics (£4.45 million ) sold off the stock and rights to the Enterprise calculator and the pocket TV to Binatone to recover some of its investment since the company was making a £1.98 million loss on turnover of £6.39 million. Sinclair resigned from Sinclair Radionics and moved to his new start-up, Sinclair Instruments Ltd, later called Science of Cambridge, and then Sinclair Research. (There is a brief history of Clive Sinclair, his companies, his calculators, and other products in the article Clive Sinclair and the pocket calculator in the Collecting Calculators section of this site.)

Radionics Products Ltd. appears to have secured the rights and probably parts and moulds to the Oxford models, on which this is based. Radionics Products specialised in electronics kits, so this calculator could have been assembled from a kit.

Name label

Name label and blanked off adapter socket on the right.

By this time it was very difficult to make a profit from calculators, as Sinclair had found and had moved on to other things, such as personal computers.

This was a very late use of LED (Light Emitting Diode) displays in a calculator.

Vintage Calculators

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