World’s First Single Chip Scientific Calculator

Sir Clive Sinclair tells a good yarn about how his company came up with the world’s first single-chip scientific calculator.

Sinclair was the UK’s leading electronics entrepreneur in the 1960s, 70s and 80s, pioneering the trail for a host of start-up electronics companies from Acorn to ARM to the mega-cluster of entrepreneurial activity thriving in Cambridge today. Sinclair’s companies brought out a string of innovative products from pocket transistor radios, to hi-fi gear, pocket TVs, one of the earliest digital watches and pocket calculators, and a sub-£100 personal computer which became the largest selling computer in the US. Sinclair’s story about the first single-chip scientific calculator takes place in 1972. “We did it by taking an existing TI chip which was a four function calculator chip”, recalls Sinclair, “TI had made it internally programmable – you could change the ROM – but it had only three registers.” “We re-programmed that, much to TI’s amazement, to create a full scientific calculator.” “A friend of mine, Nigel Searle, a computer scientist, did the programming, and I did the algorithms because no algorithms existed at that time which would have worked in just three registers.” “We went to Texas, stayed in a hotel room, and did the whole job in a few days. We took the programme into TI, then went back and collected the chip.” “TI were completely baffled by this”, remembers Sinclair, “there was a chap at London University, a professor who specialised in algorithms, and he couldn’t figure out how it could ever be done in just three registers. He thought it was technically impossible.”

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  1. June 24, 2008 16:10

    See attached URL for intersting UK history of first single chip calculator and potentially first microprocessor (or microcontroller).

  2. charles jackson
    September 30, 2007 22:12

    I had a Cambridge calculator in the 1970’s which used reverse Polish entry- no-one asked to borrow it after the fist try!

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