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.
This old circuit for circuit breaker cars was found in a 1963 publication. The transistors are...
This circuit was obtained in a 1973 national publication, translated from an English publication of the...
Found in an October 1992 Radio Electronics magazine article, this circuit generates a low-power tone in...