Incandescent lamps monitoring device in motor vehicles - has circuit permanently connected to voltage source, with lamp switch inserted into lamp connection

摘要

A measurement resistor is connected in series with the monitored lamp. There is a device which monitors the voltage drop across the resistor by means of a differential amplifier whose output controls a display device signalling absence of voltage drop or too low voltage drop. The monitoring device is connected to both terminals of the supply voltage, independently from the lamp (L1, L2) switch position. The switch is inserted in the connection to the monitored lamp (L1, L2).