We found this circuit in a 1968 Electronics World. It fires a buzzer if the ignition key is turned on and the headlight is off. The circuit uses an included oscillator buzzer like the Sonalert.
This circuit was obtained in a documentation for radio amateurs from 1975. With it we can use a...
Only for reference this is a circuito f a commercial receiver of the year 1958. The circuit uses...
This circuit is from an old American publication. The indicated transistor is oversized as the 15 V...