Antidazzle circuit for vehicle rear fog-lamp - is based on two photodetectors which have different time constants for general brightness and following headlights

摘要

Two photoelectric detector circuits (1,2) incorporate differential amplifiers (5,5') and timing resistor-capacitor combinations (R1,C1;R2,C2). Their outputs are compared (6) and the result is AND-gated (7) with signals from fog-lamp and headlamp switches to operate a power transistor (9) and relay (10,11) controlling rear fog-lamps (12). The fast-response detector circuit (1) faces rearwards to detect the headlights of a following vehicle. The slower circuit (2) responding to variations in visibility can be installed in any suitable position. USE/ADVANTAGE - The lamps are switched automatically in accordance with the risk of dazzle for the driver of a following vehicle.