Transistor gain meter (CB20522E)

This circuit was found in a publication in the 1950s, mainly applying to germanium transistors of the time.

Complete Timer (CB18775E)
This circuit has an LED indication of the timing progress, having been found in an old...
Infrared Vision (CB24310E)
This circuit is from a Radio Electronics magazine from August 1974. It used one of the first...
Nicad Automotive Charger (CB9538E)
This charger is powered by the car's 12 V socket, the number of diodes being calculated according to...