Automatic vehicle headlamp illumination regulator - uses photocell to detect ambient light and light from approaching vehicles to control electronic circuit adjusting intensity

摘要

The luminance of motor vehicle headlamp is automatically adjusted to the general level of illumination and to the presence of an oncoming vehicle by a photo resistor (1), mounted at the front of the vehicle, driving an electronic circuit to regulate the curretn supplied to the vehicle headlamps. The photo resistor (1) is connected in the base circuit of a transistor (T1) with its emitter driving the bases of two parallel connected transistors (T2,T3) which carry the current to the headlamps (7,8). An iron cored inductor (4) is connected in parallel with these transistors and smooths the changes in headlamp luminance.