Determining proportion of faulty leds in a traffic light display

摘要

Disclosed is fault detector for determining a proportion of faulty LEDs in a traffic light display having a plurality of LEDs. The fault detector is comprised of a bridge circuit having a reference arm and a sensing arm formed from the LEDs aranged in parallel. The bridge circuit becomes unbalanced upon a fault in one or more of the LEDs. The fault detector also includes a differential amplifier for determining when the bridge cricuit is unbalanced.