A halogen bulb, like incandescent lights, use a filament. Halogen lights differ because they use a tungsten filament and are encapsulated and pressurized with halogen gases. The combination of the halogen gas and the tungsten filament produces a chemical reaction known as a halogen cycle which increases the lifetime of the filament and prevents darkening of the bulb by re-depositing tungsten from the inside of the bulb back onto the filament. Because of this, a halogen lamp can be operated at a higher temperature than a standard gas-filled lamp of similar power and operating life.
In addition, the halogen cycle productes a “whiter” color (3000K) than its incandescent counterpart. One of the many benefits of halogen light bulbs is the higher Lumens per Watt (12-36) and longer rated lives (2000 – 5000 hrs) than the incandescent. However, higher operating temperatures do present some applications challenges. Special care should be used when considering halogen light in heat sensitive areas.