This protective circuit for power lines was found in a Radio Electronics from November 1957. The transistor used can be any general-purpose transistor such as the CK722.
This circuit for semiconductor laser excitation and modulation was found in an American...
Simply place the tool or object you want to magnetize inside the coil and briefly press S1. The...
This circuit is from an old publication from the 90s, but it can be adapted to operate with LEDs....