HP Calculator Heritage HP 25 - 1975
The HP 25 Programmable Scientific Calculator was released in 1975 and followed a year leter the HP 25C Programmable Scientific Calculator. This advertisement appeared in a Technical Journal in late 1976.
Caption: Introducing the first pocket programmable that remembers your programs and data even when it’s turned off. It’s called the HP-25C and incidentally, the ‘C’ stands for ‘Continuous Memory C-MOS’ technology.
Hewlett-Packard Company - Corvallis Division