This 50 kHz to 250 W circuit was found in an old RCA documentation. The transformer is a commercial type of the time and the output voltage is 80 to 90 V.
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...