Describes a circuit for an audible alarm which sounds when the door is opened with the lights on. An extra feature is a time limit so that the alarm does not continue to sound if the door is left open with the lights on. A diode detects the closure of the necessary switches and feeds current to the alarm. This is an NE555 timer IC connected as an astable oscillator, running at audio frequency. The output from this component is sufficient to directly drive the speaker.
Car lights-on warning
Autolicht an, Warnsignal
Practical Electronics ; 19 , 8 ; 68
1983
1 Seite
Aufsatz (Zeitschrift)
Englisch