This circuit was obtained from a 1967 GE SCR manual. The SCRs must be rated for the wattage of the controlled heating element.
This well-known siren configuration using complementary transistors is from a 1980s documentation. The...
This circuit was found in an old American magazine and could make use of more modern components...
This circuit is from the Philips integrated circuits manual of 1990. It is intended for magnetic...