This circuit for alternating current loads has a built-in timer. SCR2 is according to the motor current and must be equipped with a heat sink. The circuit is from a 70s GE documentation.
This is one of the possible configurations using the LM139, 239 or 339 voltage comparators. The...
Found in a 303 Circuits from the 90s, this circuit converts signals from the 10 kHz to 150 kHz...
This circuit is from a Radio Electronics issue of May 1972. It consists of a commercial heating...