Sinclair Cambridge Programmable
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Sinclair Cambridge Programmable |
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Sinclair Cambridge Programmable / Radio Shack EC-4001. Display is 8 digits, red LED (made by National Semiconductor). Scientific programmable. Integrated circuits - National Semiconductor MM5799EHY/N and DS7784N, here date coded early 1977. 9v (PP3 battery) - a "pregnant" model, see photograph below. 50 mm x 111 mm x 28 mm. Made in England. The Radio Shack EC-4001 model was supplied by Sinclair to the U.S. "Radio Shack" chain of electronics stores. |
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The back of the calculator, showing the "pregnant" bulge of the battery compartment, enlarged to take a 9v PP3 battery rather than the AAA pen-cells that the Cambridge casing had been designed for. This bulge drastically affects the aesthetics of the pregnant models. |
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Vintage Calculators |
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© Text & photographs copyright Nigel Tout 2000-2012 except where noted otherwise. |
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