Headlights Are Electrical
Unlike household or commercial lighting, headlights effort on 12-volt administer now that originates either from a automobile battery or alternator. The headlight has two electrical connections; one nourishment is a ground, or detrimental, nourishment that is "grounded" to the vehicle chassis as a send means for the electrical current. The other, positive, electrical feed is routed to the headlight by way of a series of wires, first stopping at a fused link for protection; if the headlight should short-circuit, or if there should be some sort of electrical problem, the fuse can interrupt the electrical current and extinguish the headlight. After the fuse, the wiring continues into the vehicle's passenger cabin, where it is controlled by a simple on/off switch, though some vehicles also offer computer control for automatic headlight operation. Finally, the electrical current flows to the headlight, where it excites molecules in a halogen or xenon bulb to produce light.
Headlights Illuminate the Road
When the halogen or xenon (or, in some newer models, LED) bulb illuminates, it is not capable of fully illuminating the roadway alone. Instead, the light is concentrated and directed into a reflector; the reflected, highly concentrated light shines on a series of angled mirrors to amplify its power, providing a fully illuminated roadway. Depending on the vehicle model and available space, some manufacturers also choose to direct the concentrated light directly out onto the roadway by using a configuration known as a "projector beam;" in this configuration, the amplification of the light source is performed inside the headlight and shot outward much like the beam of a movie projector, eliminating the need for further reflection.
Both headlights work the same way, are operated by the same switch and may even be combined into the same headlight assembly for a smoother appearance.
