Why did so many early / cheap calculators use 9V batteries?

[Thomas Okken]

(03-29-2018 07:34 PM)Maximilian Hohmann Wrote:  

(03-29-2018 07:03 PM)Dieter Wrote:  But it's not if you look at AAA cells.

In my recollection of the 1970ies and 1980ies AAA cells were almost nonexistent. You needed to go to a camera store and buy them at 3 or 4 German Mark a piece (or 2000 Italian Lire as I lived in Italy then). The usual places where one went to buy batteries did not have them. 4,5V "flat batteries" yes, because they were common for flashlights, but AAA I don't remember at all. And I never owned anything that needed AAA cells then. My grandmother had a calculator "Triumph/Adler Lady" with these batteries, but that must have been in the very late 70ies, and it was the first time I ever saw this kind of battery.

In 1976 or thereabouts, I had a Sinclair Scientific, which ran on four AAA cells. That was hideously expensive, especially for a kid with a modest allowance. Eventually I switched to using 4.5V flat batteries, strapped to the calculator with Scotch tape. Bulky, but much more affordable! I totally understand why later Sinclair models used 9V batteries, even though that necessitated an ugly bulge at the back of the case (which was otherwise quite elegant).

http://www.vintagecalculators.com/html/s...tific.html
http://www.vintagecalculators.com/html/c...mable.html