# What does the current vs voltage graph of a halogen look like?

I have a halogen light with a tungsten filament. It is rated 500w at 130v but I am running it from an inverter in my car that is putting out 110v. I would like to know what the actual power usage of this lamp is at 110v.

When I was a Sophomore in high school I had a physics lab where I calculated the temperature of a tungsten filament by measuring the current and then doing some calculation-which I can't pull out of my brain at the moment.

I am guessing that I am not the first person to do this and there must be some sort of curve that plots the current vs voltage of a halogen. If anyone knows of such a graph - or better yet some equations I could use to solve for an exact number, I would appreciate it.

EDIT: Ok, so I answered my original question, but if someone can give me actual equations instead of the mediocre graphs I found, I would be happy.

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The question(v2) is possibly better suited for electronics.stackexchange.com – Qmechanic Jan 7 '13 at 8:14