This circuit was found in a 73 magazine for radio amateurs from the 90s. The circuit uses high voltage transistors and the relay is high voltage as well.
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...