DIYbanter - View Single Post - Strange problem with low energy light bulb

Lostgallifreyan

(Don Klipstein) wrote in
:

The steepness of that curve alone is enough to make large changes in
output of visible lumens with small changes in voltage.

Yes, quite true. But at full voltage most 120V incandescents 60
watts
or more are about 4.5-8% efficient at converting electricity to
radiation in the 400-700 nm range.

Is this by calculation or measurement? I was hoping you or someone else
would comment on that from experience with it. Those lower figures are so
common that they must have come from somewhere, and not all from looking
only at the strongest wavelength or omitting something in calculation. I've
never seen claims of 6 to 7% for a 100W lightbulb before, and I'm sure I
would if measurements routinely reported it.