Compucorp 324G

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The first technical-scientific and also statistical programmable pocket calculators came from the American company Compucorp. If a calculator fits in a small briefcase, it may also be considered as a pocket calculator. At least the Compucorp calculators were battery powered. In the bureau machine encyclopedia from 1973 (press deadline Oct 1st, 1972), hp was just offering its hp 9810.

Like many other calculators from the time around 1970, this one contained customer specific American ICs (see page "circuit boards"). Four big nickel-cadmium accumulator cells served as power supply. The energy-saving CMOS technology wasn't mature enough, and only gas discharge lamps were available as display, which needed high voltage and high power thus requiring a voltage inverter.

The possibilities of programming the calculator are very humble: only sequences of key presses can be saved, conditional branches are not possible. The program memory can be divided into two parts to store and execute two different programs. It is also possible to save the memory to an external medium, a cassette recorder.