This circuit was found in a PE Hobbyst Handbook of 1989. It uses a black light fluorescent of the time. Small fluorescent black light from 1 to 4 W can be used.
This circuit uses a capacitor to store energy. The capacitor is charged by closing S1 by a moment. Them,...
This circuit is both a signal injector and a signal follower. A key selects the operating mode. The...
The difference between this circuit and the previous one is that it uses PNP transistors. The...