hp 25

This HP25 is the first and only calculator I ever bought. And that was in 1977...


I still have the books that came with it.




Jacques Laporte has a nice site about HP calculators where I found the power supply schematic.

source: Jacques Laporte

This calculator was manufactured from 1975 to 1978. It was succeeded by a cmos version, the HP25C.

hp calculator museum
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