Electronic detector system for vehicle turn indicator flashers - has transistors detecting voltage across relays and further transistors connected to flasher repeater

摘要

A detecting device monitors the turn-indicating flashers of a trailer. It comprises flasher relay contacts in the supply circuits to the left and right hand flasher bulbs and voltage-detecting transistors connected by resistors to the relay contacts, and by transistors to the flasher repeater lamp to give functional indications. The lamp is lit continuously if the chosen bulb is working, intermittently out of phase if the non-chosen bulb has failed, and not at all if the trailer is not connected. The lamp may be connected to the collector of a further transistor whose base is biassed by one or two diodes in series, and whose emitter is connected to a small resistor.