The incandescent light bulb, incandescent lamp or incandescent light globe makes light by heating a metal filament wire to a high temperature until it glows. The hot filament is protected from air by a glass bulb that is filled with inert gas or evacuated. In a halogen lamp, a chemical process returns metal to the filament, extending its life. The light bulb is supplied with electrical current by feed-through terminals or wires embedded in the glass. Most bulbs are used in a socket which supports the bulb mechanically and connects the current supply to the bulb’s electrical terminals.
Incandescent bulbs are produced in a wide range of sizes, light output, and voltage ratings, from 1.5 volts to about 300 volts. They require no external regulating equipment, have low manufacturing costs, and work equally well on either alternating current or direct current. As a result, the incandescent lamp is widely used in household and commercial lighting, for portable lighting such as table lamps, car headlamps, and flashlights, and for decorative and advertising lighting.
Some applications of the incandescent bulb use the heat generated by the filament, such as incubators, brooding boxes for poultry, heat lights for reptile tanks,] infrared heating for industrial heating and drying processes, and the Easy-Bake Oven toy. This waste heat increases the energy required by a building’s air conditioning system.
Incandescent light bulbs are gradually being replaced in many applications by other types of electric lights, such as fluorescent light bulbs, high-intensity discharge lamps, and light-emitting diodes (LEDs). These newer technologies improve the ratio of visible light to heat generation. Some jurisdictions, such as the European Union, are in the process of phasing out the use of incandescent light bulbs in favor of more energy-efficient lighting.
Although the incandescent light has many uses, due to the lack of efficiency, the United States government has mandated that all standard incandescent light bulbs (40w – 100w) be phased out by 2014 (estimated time). Due to this consumers will need to begin using other more efficient technologies to meet there needs.