Busicom LE-100A handy




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	Busicom LE-100A "handy"



	Busicom LE-100A "handy" Display is 10 digits red LED. Four-function. Integrated circuit - Texas Instruments TMS0106 (here date coded week 11 of 1973). Batteries - 6v, 4x AA. 67 x 124 x 25 mm (2.6" x 4.9" x 1.0"). Went on sale in September 1972. Made in Japan by Nippon Calculating Machine Corporation. This is one of the Busicom "handy" models (the first was the LE-120A) which were the first pocket-sized calculators. This model uses a Texas Instruments plastic packaged "calculator on a chip" supporting a 10-digit display. This chip was cheaper than the Mostek ceramic-packaged chip supporting a 12-digit display used in the LE-120A and LE-120S and so resulted in a cheaper calculator. The TI chip also has the much more useful floating decimal point rather than only the fixed decimal point of the Mostek chip.



	The On-Off switch is on the lower edge of the calculator, with the decimal point setting switch below the keys.



	The electronic components are packed onto two small circuit boards behind the keyboard. On this board the black package of the Texas Instruments TMS0106 "calculator on a chip" integrated circuit can be made out on the left, behind the components at the front.

The introduction in late 1970/early 1971 of the Mostek MK6010 "calculator on a chip" integrated circuit combined with the use of 7-segment LEDs made it possible to fit all of the electronics of a calculator into a very small space, so producing the first truly pocket-sized calculator, the Busicom LE-120A "handy".
Shortly afterwards, Texas Instruments announced that it was developing a "calculator on a chip" too. This was the TMS0106 which was used in the Busicom "handy" range in the LE-100A featured here.

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	© Text & photographs copyright Nigel Tout 2000-2009 except where noted otherwise.