On 24 Dec 2005 10:35:20 -0500, wrote:

Joseph Meehan wrote:

Edwin Pawlowski errs again:

There was also a thread recently about dimming halogen lights. they
burn out faster IIRC

Dimmed bulbs burn out faster? :-)

Halogen lamps do. They require a certain internal temperature of the
inside glass envelope to start the halogen cycle.

http://www.goodmart.com/facts/light_...gen_cycle.aspx

I don't see that there. I can imagine it could go either way. A lower temp
filament will evaporate less, so the bulb might last longer. How long would
it last at 10% power? At 1%? At 0.0001%? :-)

Incandescent bulbs have a minimum starting voltage? :-)

Well a minimum voltage at which they will emit visible light.

Every black body above absolute zero emits some visible light.

It would emit EM radiation (because of this, an electric heater is NOT
100% efficient). Would it always be in the limited frequency range
this is visible to humans?


m Ransley wrote:

A 100 watt bulb dimmed to 60 watts should put out less light than a 60 watt
will. A Kill-A -Watt meter is good to have around

That and measure the light output.

Easy, with a grease spot photometer. Move a 3x5 card with a grease spot
between dimmed and undimmed bulbs until the spot disappears, when it has
equal illumination on both sides and outputs are inversely proportional
to the square of the distance from each bulb.

Nick
--
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Mark Lloyd
http://notstupid.laughingsquid.com

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