Found in American documentation from the 90's, this circuit is very current and can be implemented with transistors of general use. Never use a power supply without a transformer.
This transmitter, found in Raytheon documentation from 1957, has a range of a few meters. L1 can...
Found in a 1967 RCA power manual, this circuit uses an ordinary neon lamp to fire a triac. The...
This circuit was found in the July 1992 Radio Electronics magazine. Sensitivity adjustment is made...