| You do have typical electric light bulbs at home | | | | smaller space. The glass encasing is also different |
| and you see them working every day. Typically, | | | | because it is infused with quartz which resists |
| they are made of a tungsten filament encased in | | | | temperature extremes. If the bulb were made |
| a thin and frosted glass. In this glass encasement | | | | from glass alone and it's too close to the filament |
| is not vacuum but a nonreactive gas which is | | | | that is hot, it can melt or burst instead of |
| either nitrogen or argon. As electric current runs | | | | withstand the extreme heat. |
| through the thin filament, it heats up the thin wire. | | | | The name halogen lamp comes from another key |
| The temperature gets extremely high, about | | | | element found inside the glass bulb. While typical |
| 2,500ºC and the thin tungsten wire glows white | | | | bulbs contain an inactive gas like argon or nitrogen, |
| hot. This process is known as incandescence, and | | | | halogen bulbs contain a halogen gas, such as |
| light bulbs that undergo this kind of process are | | | | iodine, inside the bulb. |
| called incandescent bulbs. | | | | The role of the halogen gas inside the bulb is |
| Incandescent bulbs are not quite efficient, | | | | crucial to its lifespan, as it prevents deposition of |
| releasing a great deal of heat and lasting | | | | the vaporized tungsten atoms onto the inner |
| approximately a thousand hours before getting | | | | glass walls of the bulb. Instead, the atoms |
| busted. These lamps release too much heat for | | | | combine with halogen gas and this process |
| the light they produce and this means that much | | | | prevents darkening of the glass bulbs. Tungsten |
| of the electric energy is being converted to heat, | | | | atoms are deposited onto the filament once again. |
| which is a waste energy, instead of light. Since the | | | | This repetitive process prolongs the life of the |
| major purpose of lamp is to generate light, | | | | tungsten filament and therefore the life of the |
| thermal energy is useless. | | | | lamp as a whole. This is why these types of light |
| Aside from generating so much heat, what | | | | bulbs are able to last longer than ordinary bulbs |
| contributes to the low efficiency of incandescent | | | | and can withstand higher temperatures. With the |
| lamps is their typically short lifespan due to the | | | | same energy input as an incandescent bulb, a |
| rapid burning out of the tungsten filament. In | | | | halogen bulb burns with greater intensity, signifying |
| extremely high temperatures, some of the | | | | efficiency. |
| tungsten atoms leave the filament and become | | | | However, because the quartz bulb is so close to |
| deposited on the inner walls of the glass bulb and | | | | the glowing filament, it gets extremely hot too |
| cause darkening, further lowering the efficiency of | | | | which is a reason you should be cautious when |
| the lamp, as the darkened glass bulb reduces light | | | | handling halogen lamps at work. Halogen lamps |
| emission. The tungsten filament does not vaporize | | | | operate with optimum efficiency at expectedly |
| uniformly. Instead, evaporation occurs on weak | | | | extreme temperatures and, because of this, they |
| spots, where vaporization of tungsten occurs | | | | can create fire hazard. This is why safety codes |
| more rapidly. Finally, a break occurs in this region | | | | for such bulbs require them to be protected by |
| and the light bulb gets busted. | | | | grille or a special housing fixture to avoid direct |
| The difference between a halogen lamp and an | | | | contact with curtains and flammable materials. |
| incandescent one is that the former is better in | | | | Also since the quartz bulb releases UV-B rays, too |
| many aspects. Although both have the same key | | | | much skin exposure to halogen lamps can cause |
| factor, the tungsten filament, both have different | | | | sunburn-like symptoms. This is why some bulbs |
| features. Halogen light bulbs are smaller than | | | | are coated with UV-B filter to reduce radiation |
| incandescent bulbs to concentrate heat in a | | | | emission. |