Found in an EDN from the 1980s, this circuit uses a double 555. The circuit activates a relay that controls a horn or siren. Next to the diagram we have the timings.
Used with old projector films, this circuit found in Signalite documentation from the 1980s,...
This circuit was obtained in 1981 documentation. It is an FM transmitter that can serve to emit...
This is the traditional source using the LM317 3-terminal regulator circuit. The same source can...