Found in a Popular Electronics from the 1990s, this circuit is a 1-digit counter that advances under the command of S2. The circuit can be expanded to more digits.
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...