The Sinclair Scientific Calculator, not to be confused with the Sinclair Cambridge Scientific calculator, was released in 1974. Hewlett-Packard's HP-35, the first handheld scientific calculator, had only been released two years before. Clive Sinclair wanted a cheap scientific calculator to compete with the new handheld scientific calculators that were being released. This faced a number of issues while trying to use a chip built for four-function calculators (the TI TMC0805). However with the help of Nigel Searle, who joined Sinclair Radionics in 1973, the company went on to build the first single-chip scientific calculator which had 12 functions including sine, cosine, tangent, arcsine, arccos, arctan, log, and exponentiation into the chip by re-programming the three-register IC.

The Sinclair Scientific initially cost £49 +VAT, or around $99 +tax in the US, compared to the $395 that the HP-35 cost. However, there were a number of limitations to the Sinclair Scientific. While it could calculate scientific equations, it was limited in what it could do compared to other scientific calculators. It was also slow, with some equations taking up to 15 seconds to be calculated.

The Sinclair Scientific uses reverse Polish notation (RPN). The calculator has a Bowmar LED display, and displays only in scientific notation - five digit mantissa and two digit exponent. It is powered by four AAA batteries.

The calculator used the same casing as the existing Cambridge-series of calculators from Sinclair. However, the Cambridge Scientific was not released until 1976.

The Sinclair Scientific was also available as a build-it-yourself kit. By December 1975 it cost only £9.95 including VAT.

Ken Sherriff built an emulator of the Sinclair Scientific calculator which can be found here on his website

Manufacturer: Sinclair Radionics
Date: 1974

This exhibit has a reference ID of CH49685. Please quote this reference ID in any communication with the Centre for Computing History.

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