This circuit is intended for detecting 3 levels power grid voltage, and it can be adapted to operate with the most diverse voltages. The circuit uses neon indicator lamps.
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...