Recently I was down at my grandfathers house and while I was there I helped my grandfather change out some lights, but these were halogen lights! After hearing my grandfather complain for some time about how there are too many different light bulbs now a days I got to thinking what makes halogen lights so darn special?
I got to looking in on it to see how exactly halogen lights worked and found some interesting things. I found that both a regular light bulb and halogen light bulbs have a tungsten filament that burns at an extremely high temperature. The difference in the halogen lights though is that the tungsten burns at a much higher temperature that would melt the glass of a regular bulb. So the filament in a halogen light is encased in a quartz envelope, therefore it can continue to burn at extremely high temperatures.
The other big difference in the halogen lights though is the gas inside the bulb, while a regular bulb usually has some kind of gas like argon or nitrogen, halogens have a gas from the halogen group, hence the name. The halogen gasses contain a special property that makes it so at very high temperatures they combine with the vaporized tungsten atoms and redeposit on the tungsten filament. This means they create an almost regenerating process that makes it so bulbs can last much longer and be much brighter. This comes at a cost since the bulb must be much hotter but overall the longevity of the bulb makes up for the heat loss.
The simple light bulb has gotten more and more efficient over the years and even if my grandfather's not happy about it, engineers sure are.
Picture from thehigheredcio.com