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 was found in an American magazine 73 for radio amateurs of the 80s. It is an...
This circuit was found in a French magazine Toute LÉlectronique from 1978. Transistors are not...
This circuit without any capacitor operates based in the time the transistor need to turn on. The...