Found in the July 1994 Electronics Now magazine, this circuit drives a relay up to 12 V depending on the power supply. The transistor can be general purpose.
This circuit is from a 1968 General Electric manual. It produces a pulse of light when fired,...
This circuit is from a 2001 Poptronics. The magazine no longer exists, but the components used are...
This circuit is from 1990 documentation. It uses a bridge with LEDs and the potentiometer must be...