Sinclair Scientific

Sinclair Scientific

Sinclair Scientific calculator photographed c. 1974
Type	Scientific
Manufacturer	Sinclair Radionics
Introduced	1974
Cost	GB£49 + VAT
Calculator
Entry mode	RPN
Precision	5 digit significand, 2 digit exponent
Display type	Light-emitting diode
CPU
Processor	Texas Instruments TMC-0805
Programming
Other
Power supply	4x AAA batteries (Scientific) 1x PP3 battery (Scientific Programmable)
Dimensions	50 by 111 by 19 millimetres (1.97 in × 4.37 in × 0.75 in) (Scientific) 73 by 155 by 34 millimetres (2.9 in × 6.1 in × 1.3 in) (Scientific Programmable)

The Sinclair Scientific calculator was a 12-function, pocket-sized scientific calculator introduced in 1974, dramatically undercutting in price other calculators available at the time. The Sinclair Scientific Programmable, released a year later, was advertised as the first budget programmable calculator.

Significant modifications to the algorithms used meant that a chipset intended for a four-function calculator was able to process scientific functions, but at the cost of reduced speed and accuracy. Compared to contemporary scientific calculators, some functions were slow to execute, and others had limited accuracy or gave the wrong answer, but the cost of the Sinclair was a fraction of the cost of competing calculators.

In 1972, Hewlett-Packard launched the HP-35, the world's first handheld scientific calculator. Despite market research suggesting that it was too expensive for there to be any real demand, production went ahead. It cost US$395 (about GB£165), but despite the price, over 300,000 were sold in the three and a half years for which it was produced.

From 1971 Texas Instruments had been making available the building block for a simple calculator on a single chip and the TMS0803 chipset appeared in a number of Sinclair calculators.Clive Sinclair wanted to design a calculator to compete with the HP-35 using this series of chips. Despite scepticism about the feasibility of the project from Texas Instruments engineers, Nigel Searle was able to design algorithms that sacrificed some speed and accuracy in order to implement scientific functions on the TMS0805 variation.

The Sinclair Scientific first appeared in a case derived from that of the Sinclair Cambridge, but it was not part of the same range. The initial retail price was GB£49.95 in the UK, and in the US for US$99.95 as a kit or US$139.95 fully assembled. By July 1976, however, it was possible to purchase one for GB£7.