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 configuration uses the 4 gates of a 7401 integrated circuit. The capacitors determine the...
This is a precision half-wave rectifier, suggested by Texas Instruments. Diodes are commonly used,...
This circuit is suggested by National Semiconductor in its 1994 Linear Applications Handbook. The...