Sinclair Executive
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The Sinclair Executive was Clive Sinclair’s first venture into the pocket calculator market. The Executive was the world’s first “slimline” pocket calculator. It was variously described as “a piece of personal jewelry” (New Scientist) and “at once a conversation piece, a rich man’s plaything and a functional business machine” (Design Magazine). An example of the calculator is displayed at the Museum of Modern Art in New York.
The Executive was launched on August 1972 at the price of £79.95 plus VAT, at that time a very large sum of money. It weighed only 2.5 ounces (~70 grams) and measured 5.5 × 2.25 × 0.4 inches (14 × 5.7 × 1.0 cm).
Sinclair had to overcome the problem of the LED display’s power hungry nature in order to build a calculator driven by four hearing aid type batteries. The marketing information claimed circuitry with a light appetite for electricity but in reality all they had done was to switch the power on and off at a rate that allowed the display and memory to persist. This had the effect of extending battery life. The batteries still only lasted for a few hours of use and also had the tendency to blow up, destroying the calculator; the latter possibly being part of the reason why they are so rare nowadays.