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Comment: But is it REALLY more effecient? (Score 2, Interesting) 559

by RobRyland (#28176301) Attached to: Laser Blast Makes Regular Light Bulbs Super-Efficient
A lightbulb works because the filiment gets really hot and glows with blackbody radiation. All of the electric power that goes into the bulb is radiated. So in some sense, the incandecent bulb is already 100% effecient. the only problem is that most of the radiated energy is at infrared frequencies and doesn't do anything to light the room for human eyes. If you increase the emmisivity of the filiment to 100%, it is not obvious that you increase the effeciency of the bulb one iota. In fact, I would guess that the effeciency of the bulb goes down, since the filiment temperature will go down (since you radiate more power at a given temperature) and more of the radiation will be in the IR. Now, if he can change the surface of the filiment so the emmisivity is very high in the visable but very low in the IR, then and only then will he be onto something. -Rob (and yes, I am in fact a physicist)

Comment: Re:Details up front (Score 1) 609

by RobRyland (#26367095) Attached to: New Energy Efficiency Rules For TVs Sold In California

The sticker on the back doesn't tell you how much it uses in practice, it tells you the maximum it will ever use. It's useful for sizing circuits and picking fuses, but not for estimating running costs. The label on the back doesn't tell you if it uses 80W or 1W in standby. It doesn't tell you if the maximum rating applies during normal viewing, or only for two seconds at startup.

To find out how much power something is using you really need a "Kill-A-Watt" meter. Google it. They are quite handy! -Rob

Dreams are free, but you get soaked on the connect time.