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Sinclair Instrument Wrist Calculator

The Sinclair Instrument Wrist Calculator was a simple 8-digit calculator, that was only sold as a mail-order kit. It was released in February 1977 by Sinclair Instrument, a company ran in parallel with Sinclair Radionics. It originally sold for £9.95 (plus VAT).

The wrist calculator ran on six mercury hearing-aid batteries, which only lasted about an hour and a half, and required the user to disassemble the unit to change them.

The calculator had a three-position button to access extra functions, such as memory and square root.

Sales were not great, only around 10,000 were reported sold. Reliability meant that a great many were returned to Sinclair, as was the case with the Sinclair digital watches.

Manufacturer: Sinclair Instrument
Date: February 1977

This exhibit has a reference ID of CH52845. Please quote this reference ID in any communication with the Centre for Computing History.


Sinclair Instrument Wrist Calculator

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