The fabulous illustrated history of the pocket calculator

In the 1970s, there was a boom in pocket calculators, driven by the plummeting costs of their electronic components, and an industry that had once prided itself on its high-end offerings for serious business users found itself rethinking the nature of the calculator, producing "ladies' calculators," calculators for kids (accompanied by bestselling books of "calculator games") and all manner of weird form-factors.

Pulp Librarian's Twitter-thread recounting this tale is an illustrated wonderland, full of cul-de-sacs, forgotten lore, and wonderful oddments.

Canon was one of the first to launch a pocket calculator in 1970. The Pocketronic used Texas Instruments integrated circuits, with calculations printed on a roll of thermal paper.

Sharp was also an early producer of pocket calculators. Unlike Canon they used integrated circuits from Rockwell and showed the calculation on a vacuum fluorescent display. The carrying handle was a nice touch!

The next year brought another big leap: the Hewlet-Packard HP35. Not only did it use a microprocessor it was also the first scientific pocket calculator. Suddenly the slide rule was no longer king; the 35 buttons of the HP35 had taken its crown.

By 1974 Hewlett Packard had created another first: the HP-65 programmable pocket calculator. Programmes were stored on magnetic cards slotted into the unit. It was even used during the Apollo-Soyuz space mission to make manual course corrections…

But the biggest shake-up of the emerging calculator market came in 1975, when Texas Instruments – who made the chips for most calculator companies – decided to produce and sell their own models.