The integrated circuit used in this application is uncommon, but equivalent operational ones can be used. The circuit is from the Signetics integrated circuits manual from 1972.
This circuit, from the 90's, is intended for operation with vinyl record players of the time, as...
Using a zener diode it is possible to change the linearity of the scale of an analog instrument by...
Found in American documentation from the 1980s, this circuit prolongs the ringing of a doorbell or chime...