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

[Paul Berger (Canada)]

(03-29-2018 05:32 PM)KF6GPE Wrote:  I had always assumed --- and maybe someone with an EE can tell me I'm wrong --- that the 9V was easily downconverted to 5V for TTL, and during that period TTL was cheaper than CMOS, which was newer. Getting to 5V with AA's or other batteries would require four, which is more bulk.

But that's just speculation on my part.

Most of the early handhelds where mainly MOS components often PMOS, bipolar like TTL would have been too power hungry. Some may have bipolar drivers for the LED display.

Paul.