Ever wonder why a "Halogen" light bulb has that name? Well, what happens if you try to create a very bright incandescent lamp is that when pumping so much elect

Ever wonder why a "Halogen" light bulb has that name? Well, what happens if you try to create a very bright incandescent lamp is that when pumping so much electricity through a filament and heating it up to incredible temperatures you'll actually start to evaporate the filament. This is a common failure mode for incandescent bulbs, a part of the filament will get thinner due to evaporation and then the reduced thickness will increase resistance in that section, accelerating evaporation and eventually causing a break. But if you put a small amount of Bromine or Iodine gas (halogens) inside of the bulb, and a small amount of Oxygen, then the evaporated metal will form a Tungsten OxyHalide gas which will then redeposit Tungsten metal through an electro-chemical reaction back onto the filament, increasing the filament's longevity even at very high power levels.