Quote:
Originally posted by Minjin
Where are you getting this 100% efficiency stuff from? Light sources are rated in lumens per watt not some conservation of energy rating. They're also not a voltage driven device (like incandescents); they are current driven. And finally, LEDs are more effecient below their rated current than at it.
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What he means is that if you measure the ratio of light output to electricity input in wattage amounts, it will be almost 1, or 100%.
LEDs are more like 90% efficient though, there will always be some resistance to electricity. Plus if you use a resistor to put it at its rated vMax then it will only be around 70% or so due to the resistor putting off heat.
Incandescent lights are around 10% to 15% efficient

and flourescents are anywhere from 45% to 75% efficient (Depends on the ballast/transformer) if I remember correctly. The wasted energy is output in heat, which is why incandescent bulbs get so hot. It is generally the ballast of the flourescent light that wastes power, though, feel one and you will notice lots of heat coming from it. LEDs generally run only slightly above room temperature and are extremely bright for their current draw. However, they put off more and more heat as they are overvolted and are less and less efficient even if they are returned to normal voltage. Also, the current an LED draws depends on the voltage you put it at.