Alarm circuit indicating operation of vehicle lights - has electromagnetic relay providing warning sound when ignition is switched OFF and lights are left on

摘要

The audible warning is sounded when the vehicle ignition is switched off and the lights are left on. The audible signal is pref. produced by an electromagnetic relay, an alternative design including a delay relay and diodes to also act as a malfunction indicator. Connections can be made to existing wiring in the vehicle using spikes pressed through the insulation. Operation of the alarm is automatically cut-off when the lights are switched off.