h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Why do small halogen bulbs produce much greater light than ordinary light bulbs?

I think the halogen gases in them allow the filament to glow at a much higher temperature without burning out.

Thanks (incidently, it explains why, when one exploded, it caused such damage and a piece of glass melded itself into the sofa)

Yes halogen lights are hot, you do NOT want to touch them.

Thanks I already knew that.....

Traveller in Times on top
"You should also not touch the bulb when it is cold. Grease from your skin will burn, get black and create a hotspot on the bulb with the possible risk of structural failure of the bulb. "

That kind of warning is provided on the packaging. It was the brightness I was wondering about (whether enhanced by magnifying....)

Thanks anyway

> It was the brightness I was wondering about...

These filaments are brighter because they are hotter (as already explained in Post 2).

any idea of the different temperatures involved?

(and yes, I do read the answers)

I haven't been able to find any reliable figures on what temperature the filament is at. It seems to be somewhere about 3000 degrees C.

The reason the halogen bulb's filament can be hotter is this: at higher temperatures more of the filament evaporates, which in a normal bulb causes the filament to burn out. But in the halogen bulb, a reaction takes place with the halogen atoms in the gas of the bulb which cause the evaporated tungsten from the filament to be re-deposited back on the filament, causing it last longer.

Thanks a lot.... it's starting to make more sense to me.