HALOGEN LAMP FILAMENTS
Contrary to traditional incandescent lamps, halogen lamps are made with a tungsten filament because of their high flexibility, high melting points and slow evaporation properties at high operating temperatures. Halogen lamps produce light by operating at approximately 3 000 K temperature (vs 2 700K for incandescent lamps) in an atmosphere of inert gases (krypton, argon and nitrogen) with added halogen gases (Iodine and/or bromine). Because halogen lamps are usually very compact in size, the tungsten filaments are also extremely small which enable them to concentrate high light energy inside the lamp.
Since halogen lamps are designed with a tungsten filament, lamp life is proportional to the rate at which the filament evaporates, which means the filament temperature determines the life of a halogen lamp. A slight change in voltage will increase or decrease the filament temperature and may cause deterioration in lamp life.
Halogen lamps can have axial filaments or the more traditional horizontal mounted filaments. An axial filament offers better light distribution and higher lamp efficacy.
Filaments come in various shapes for many different applications. Similar to the incandescent filament designations, halogen lamp filaments are identified by a letter or letters which indicates a coiled wire (C) or coiled coil wire (CC), followed by a number to indicate the shape of the filament.
C: Single Coil
CC: Coiled Coil