Automatic Headlight Dimmer, Safe Yourself and Others

This schematic diagram shows an automatic headlight dimmer circuit for your car’s headlight, keep you safe in the dark with maximum bright for farthest visibility, but will automatically switch from high to low  beam when traffic approach to save others sight. With Q1 in moderate darkness the variable resistor must be adjusted to generate no base current through Q2. This system is triggered by headlights from other car. The high-beam lights on when there is no approaching headlights. The relay K2 is energized and K1 is not energized. Here is the schematic diagram of the circuit:

The car’s headlights will be switched to low beams when the phototransisor receives lights from other car coming from  the opposite direction, causing an increase in the collector and base current of the PNP. This substantial increase will energize the K1 relay. K2 is deenergized causing the high-beam headlights to turn off, so the low beam lamps will light.  For your convenience, the switch S1 should be located on the dashboard of your of vehicle. This switch must be turned off during the day, so that the circuit will always turn on the high beam lamp in sunlight. [Circuit’s schematic diagram source: seekic.com]