British Calculators

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Sinclair executive calculator

Clive Sinclair was very innovative in the field of consumer electronics and, for many years in Britain, was widely known as "the man who invented the pocket calculator".

This is not true since there were earlier calculators that would fit in a small pocket (for example the Busicom LE-120A "handy"). However, the Sinclair Executive, shown on the left, was the first slimline calculator and when launched in July 1972 it caused a sensation because it was the world's thinnest calculator by a long way.

The later Cambridge models were also very small and generally crammed many functions into their small size. However, the smart design of some of these, the "pregnant" models, was destroyed since they required a large bulge in the back of the case to take a 9v PP3 battery instead of the earlier AAA pen-light cells.

The Sinclair name is associated with several companies. Nearly all of the calculators were produced by Sinclair Radionics Ltd., though the Wristwatch calculator was produced by Sinclair Instruments Ltd. 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.

Sinclair calculators are known for their innovative and often elegant designs. The dates of introduction of some of the notable models are listed below. All are from Sinclair Radionics Ltd., except where noted:

Source "Sinclair and the 'Sunrise' Technology"


Known Sinclair models  :-

Sinclair models under other names :-


Thumbnail pictures are grouped here by case style.

Click on an image to go to a page with larger pictures and technical details -

Cambridge type 1

Has keys [C] and [K].

Cambridge type 2

Has keys [C] and [CE].

Cambridge type 3

Has keys [C/CE] and [K].

Has keys [C], [CE] and [%].

Cambridge Memory
Cambridge Memory (%) (type 1)
Cambridge Memory (%)  (type 2)
Cambridge Programmable
Cambridge Scientific

Cambridge Universal

Cambridge Universal
Enterprise Programmable
Executive Memory
Oxford 100
Oxford 150
Oxford 200
Oxford 300
Oxford Scientific
Oxford Universal
Sinclair President
Sinclair President

Scientific Programmable

Oxford Scientific Programmable
Wrist Calculator

Models by Sinclair under other names:

Gillette GPA
Radio Shack EC-4001

Sinclair digital multimeter in a calculator case:

PDM35 Multimeter

PDM35 Multimeter

A digital multimeter in an Oxford calculator case.

Vintage Calculators

© Text & photographs copyright Nigel Tout   2000-2019  except where noted otherwise.