This circuit was found in a 1968 US publication. Transistors used are uncommon today. The circuit can be adapted to operate with modern equivalent components.
This circuit has an LED indication of the timing progress, having been found in an old...
This circuit is from a Radio Electronics magazine from August 1974. It used one of the first...
This charger is powered by the car's 12 V socket, the number of diodes being calculated according to...