This circuit from a Radio Electronics from October 1965 shows how to obtain the action of an SCR when triggering a relay using two transistors. The relay is according to the circuit supply voltage.
This circuit for incandescent lamps was found in a 70s documentation. The circuit uses an SCR...
This circuit is from an Elementary Electronics from 1977. It can be assembled with relative ease...
This circuit detects the presence of strong signals from spy transmitters, enabling their...