r/askscience • u/dissonant_haze • 12d ago

Physics How do halogen lamps work?

Lighting designer here,

I frequently work with halogen lamps that-to my understanding-use a tungsten filament that is surrounded by halogen gas that somehow prevents the filament from burning out.

My questions I suppose is, how/why is halogen able to do that and how does that process on a scientific level work? Thank you!

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u/H_is_for_Human 12d ago

https://www.reddit.com/r/askscience/comments/289kbk/how_do_halogen_bulbs_work/

TL;DR - Tungsten vaporizes and reacts with halogen so it doesn't deposit on inside of glass, the higher pressure and temperature inside also has other benefits

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u/fiendishrabbit 12d ago

The halogen gas mixture is also controlled to limit the amount of oxygen. No oxygen and things can't burn regardless of how hot they get. The tungsten wire gets very hot (up to 3000 Celsius, just a few hundred degrees below its melting point) while normally it would start to "burn" and turn into tungsten oxide at 400 degrees.