This regulator can use BD'136 as the main transistor and as a reference next to a BC548 zener. The circuit provides a voltage of 9V from 12 to power devices that use batteries.
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...