Fault detection and correction circuit for vehicle lamps - uses transistor diode and relay logic to monitor bulb failure and to provide lost function in another bulb

摘要

Failure of headlamps or signalling lamps on a motor vehicle is detected and visually and audibly indicated tothe driver by an electronic circuit which uses voltage and current operated relays in series with each lamp to test for lamp failure. Each time the vehicle is started, the warning operates for a quarter second if all lamps are functioning, and for a longer period if a faulty lamp has previously been detected. The logic functions are performed by a circuit using transistors and diodes installed in a box (57) located in the vehicles engine compartment, while signalling circuitry is installed in an enclosure in the vehicle cabin (60). If head lamps fail the parking lamps are operated at increased power, and if signal lamps fail the parking lamps take over their function.