Page 63 - Catalog_W

Halogen lamps by their very nature are incandescent type lamps with a few special differences. The most important difference is the “Halogen Regenerative Cycle.” The halogen cycle is what gives halogen lamps their advantage, higher light output and longer life. Other benefits of halogen lamps are the ability to use smaller glass envelopes and economical use of quartz and glass alloys. Higher operating temperatures help maintain their brightness levels, produce more light in the visible wavelengths, and more efficiently convert electric current to usable light.

During assembly, a halogen lamp is filled with an inert gas just like a standard incandescent lamp; usually nitrogen, argon, krypton, or xenon. In addition to the inert gas, a small amount of a halogen compound and oxygen are added to the mix. The halogen cycle consists of four critical steps illustrated in the figures below.

Step 1: Before you energize a lamp, the gases inside are evenly distributed, the lamp is at equilibrium.

Step 2: When the lamp is energized, the halogen regenerative cycle begins as the filament heats up and the tungsten filament starts to

evaporate, known as vaporization.

Step 3: Evaporated tungsten joins with the halogen/oxygen mix and forms into tungsten oxyhalide molecules. These molecules move

around inside the envelope from lower temperature areas to the higher temperature filament, referred to as formation.

Step 4: As the tungsten oxyhalide molecules near the higher temperature filament, the tungsten is separated from the halogen/oxygen

mix. The separated tungsten is then deposited back onto the filament and reused, which is defined as deposition.

The filament heats up the deposited tungsten, evaporates it, forms it into molecules, and re-deposits it onto the filament again, continuing the halogen cycle over and over.

SEAL FILAMENT BULB

ENVELOPE

BASE

A variety of bases are used in halogen lamps.

Page 63 - Catalog_W_Lamp

Page 63 - Catalog_W_Lamp