This circuit for light modulated in frequency (FM) was found in documentation of the 90s. SUS is uncommon today, but transistors admit equivalents.
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...