These 6 to 12 V source with current up to 100 mA was found in Radio Electronics magazine from June 19666. The source has a current indicator and uses transistors of the time.
The battery charger suggested in the figure has its current limited by resistor R1. This component may...
This interesting 80's EDN circuit divides the input pulse frequency by a number given by n...
This circuit was found in a 1969 CQ magazine. It is intended for coupling telephones to radio...