A halogen bulb is a type of incandescent light bulb, introduced in 1958. The halogen bulb is capable of burning much more brightly than conventional light bulbs, and it is a popular choice for headlights and other applications for which very bright light is needed. In addition to burning more brightly, halogen light bulbs are also more efficient and have a longer life expectancy than conventional light bulbs.
The halogen light bulb uses a design very similar to that of conventional light bulbs, consisting of a tungsten filament enclosed in another material. The halogen bulb uses quartz instead of glass, however, allowing the bulb to be much smaller because quartz can withstand higher temperatures than glass and therefore may be positioned much closer to the filament. In addition, halogen light bulbs use halogen gases, instead of argon or nitrogen, two gases commonly used in conventional light bulbs.
A light bulb works by applying electricity to the tungsten filament, which heats up and puts out light. However, as the filament heats, it also begins to break down the tungsten, which begins to collect inside the bulb, often leaving dark deposits. Ultimately, the filament will break at a weak point, causing the light bulb to burn out.
The design of the halogen bulb has one very interesting property: halogen gas can combine with tungsten vapor and redeposit it on the filament of the bulb, thereby recycling energy and making the bulb last longer. The heat that halogen bulbs emit is used in the chemical reaction between the tungsten and the halogen gases, and this increases the efficiency of the bulb immensely. The halogen light bulb can withstand more heat than a conventional light bulb, which will result in brighter light as well as more recycling ability.
Halogen bulbs come with a few cautions. Like regular light bulbs, halogen light bulbs get hot. Because the quartz envelope is so close to the filament, however, halogen light bulbs get much hotter than conventional bulbs and can cause burns if handled. A halogen lihgt bulb can also start a fire if it is used near drapery or other flammable objects. In addition, handling a halogen light bulb with bare hands exposes the quartz to salts and oils in the hands and may cause a weak point. This will decrease the life of the bulb, and it is recommended that halogen bulbs be handled with gloves or cloth to prevent unnecessary contact, and wiped down if they are handled.