On Jan 27, 8:15 am, wrote:
Joseph Meehan wrote:
... if you had 10 lamps in the room you could dim them all 50% or
turn half of them off and save a little more energy.Wikipedia says the power used and light output of an incandescent bulb are
proportional to V^1.6 and V^3.4, so light is proportional to V^(3.4/1.6)
= P^2.125, no? Turning half off makes half the light with half the power,
but dimming all to 50% power only makes 0.5^2.1225, ie 23% of the light.

Making 50% of the light requires dimming them all to 0.5^(1/2.125), ie
72% of the original power. That's a lot vs a little more energy, IMO.

Then again, CFs are 4X more efficient, and some dimmable CFs have
a light output that's directly proportional to power :-)

Nick



Another Nick classic. Quick with the numbers and clueless as
usual. The guy didn't ask if a bulb that is at half brightness uses
less energy. Any dummy knows that. What he asked was whether the
energy saved at the bulb just shows up as energy wasted at the
dimmer. Which of course it doesn;t because dimmers are Triacs.