- Sinclair Executive
The Sinclair Executive was
Clive Sinclair ’s first venture into thepocket calculator market. The Executive was the world’s first “slimline” pocket calculator. It was variously described as “a piece of personaljewelry ” ("New Scientist ") and “at once a conversation piece, a rich man’s plaything and a functional businessmachine ” ("Design Magazine"). An example of the calculator is displayed at the Museum of Modern Art inNew York .The Executive was launched in August
1972 at the price of £79.95 plusVAT , which at that time was about two or three times the average weekly wage. It weighed only 2.5 ounces (~70 grams) and measured 5.5 × 2.25 × 0.4 inches (14 × 5.7 × 1.0 cm).The Executive was remarkably thin for its time, made possible by the first use of button-type batteries to power a calculator. To do this, Sinclair had to overcome the problem of the power hungry calculator electronics and
LED display. It was common to pulse the power to the LED display to reduce power consumption, but Sinclair's engineers found that it was also possible to rapidly pulse the main calculatorintegrated circuit (chip). This method of operation relied on thecapacitance of the devices in the chip to retain information during a calculation, and it was claimed that the power consumption of the chip was reduced from 350 milliwatts to about 20 milliwatts.Texas Instruments , the manufacturer of the chip, said it had not tested them operating like this, but Sinclair said that it tested all the chips before it used them ["Pocket calculator weighs in at 2.5 ounces", Electronics, July 3rd. 1972, "Electronics International" section p3E] ["Pocket calculators add up to a big market",New Scientist , 20th. July 1972, p144] [Dale, R. (1985) "the Sinclair story", London: Duckworth] . Although this had the effect of extending battery life, they still only lasted for a few hours of intermittent use and also had the tendency to explode due to overheating if the calculator was left switched on, damaging the calculator casing.See also
*
Sinclair Oxford
*Sinclair Sovereign References
External links
* [http://www.nvg.ntnu.no/sinclair/calculators/executive.htm Planet Sinclair—Sinclair Executive information]
* [http://www.nvg.ntnu.no/sinclair/calculators/executive_photos.htm Planet Sinclair—Sinclair Executive photo gallery]
* [http://www.vintagecalculators.com/html/sinclair___the_pocket_calculat.html Clive Sinclair and the Pocket calculator]
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