Re: Light output of dimmed lamps

Joseph Meehan <sligojoe_Spamno@xxxxxxxxxxx> wrote:

>> Edwin Pawlowski <esp@xxxxxxxx> 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_bulbs/halogen_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.

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

.

Relevant Pages

  • Re: Spiral fluorescent lighting - not getting anywhere near the 5 to 7 year life - anyone el
    ... If these same two fixtures each have 15W CF bulbs ... consider the CF bulb costs $3 or so, and the indec bulb costs 25 ... I never had any other than dollar store ... of light output from claimed light output, lack of a lumen figure for ...
    (alt.home.repair)
  • Re: Time to stock up?
    ... comparing the spectrum of light from a GLS lamp and a CFL: ... I would have thought the grease spot method would work for household ... Place one bulb at one end of a table, and the other bulb at the other ... Bunsen's grease spot photometer only works well with light sources of the ...
    (uk.legal)
  • Re: Another reason to hate CFLs ...
    ... If I can't find any more 60 watt pearl bulbs on the 'net, then I'm going to modify the lampholder to take a low voltage halogen downlighter bulb, and hook it to a 12v transformer. ... Over the years since this technology was vaunted as the 'replacement' for incandescent light, I have bought many examples from different manufacturers. ... Most seem to be rated to produce 80% of their maximum light output after 15 seconds. ... My daughter, who is an artist and understands a lot about colour, saw the new decoration for the first time after it had been completed and this new bulb fitted, at night, and she was horrified at the effect, asking how on earth we could have picked such horrible and mismatched colours. ...
    (sci.electronics.repair)
  • Re: Light output of dimmed lamps
    ... > incandescent and halogen lamps varies as they are dimmed? ... The light output and power of an incandescent or halogen incandescent bulb ...
    (alt.home.repair)
  • Re: What bulb voltage?
    ... >>> Then seek a bulb that was of the wattage measured. ... I think you would be reading a voltage higher than the rated ... > light output now given some formula. ... > For any particular lamp, the light output and life depend upon the ...
    (sci.electronics.basics)