The term “headlamp” is used in two different ways. In the first sense, a headlamp is a light located on the front of the vehicle for the purpose of providing illumination. Car headlamps are sometimes known as headlights. In the second sense, a headlamp is a light which is designed to be worn on the head. This type of headlamp is popular with people who need lighting, but also want their hands to be free.
Headlamps in the sense of lights which attach to the head can work in a number of ways. Some are mounted on straps which are worn like headbands, while others are mounted on clips which can be attached to hardhats and other head gear. In all cases, the goal of the design is to provide a beam of bright light for the wearer, while leaving his or her hands free. This type of headlamp is sometimes called a headlamp flashlight to avoid confusion.
Illustrations of miners often include headlamps mounted on the hardhats of the miners, illustrating one way in which a headlamp can be used. Headlamps are also very useful for campers and hikers, who sometimes encounter dim conditions, but need both hands to navigate or manipulate items. Disc jockeys sometimes use headlamps at parties so that they can see what they are doing without creating light pollution which might disrupt the mood of the event, and headlamps are also used by people who work in tunnels and other dark environments.
On cars, headlamps are critical for night driving. Technically, the assembly of lens and bulb is collectively known as a “headlamp,” while the light emitted by the headlamps is a “headlight.” However, this distinction is often blurred, even in driving handbooks and car owners manuals, so the terms are sometimes confused or misused. A pedantic auto shop might insist on using “headlamp” in discussions about replacements of broken or burned-out headlamps.
A typical car headlamp has a high and low setting, so that drivers can have bright light when they drive alone, adjusting to a low beam for the comfort of passing drivers. It is important to routinely check the function of both the high and low beams, as one or the other can burn out, and it is also a good idea to make sure that headlamps are oriented properly. They should point straight ahead, and be high enough to provide clear illumination, but low enough to avoid flashing light into the vehicles of passing drivers, ensuring that other drivers are not temporarily blinded by the light.