Physicists hell-bent on destroying the universe have come up with a
tiny LED that produces 69 Pico watts of light while using just 30 Pico
watts of power. That’s an efficiency of above 100%, which should be
impossible, but isn’t.
Last week, physicists from MIT published a paper in Physical Review Letters
entitled “Thermoelectrically Pumped Light-Emitting Diodes Operating
above Unity Efficiency.” My guess is that most physicists cringe a
little bit when they see the phrase “above unity,” because that’s
another way of saying either “perpetual motion machine” or “free
energy,” both of which are likely to get you branded as either an
eccentric (if you’re lucky) or a total crackpot (if you’re not).
Over-unity machines may be impossible, but the LED in this paper
definitely put out more than twice as much energy in the form of photons
as the researchers fed it in the form of electrons. They found that as
they decreased the electrical voltage that went into the LED, the
emitted light decreased by a direct proportion, while the input power
decreased exponentially. In other words, the less power you put into an
LED, the more efficient it gets at producing light, and if you decrease
the power enough, you can blow right past the 100% efficiency mark.
So, how does this not totally and completely invalidate the
conservation of energy? We have to look at how energy flows through the entire system, not just at the electricity in and light out. When the LED gets more than 100% electrically
efficient, it starts to cool itself down, which is another way of
saying that it’s stealing energy (in the form of heat) from its
environment and converting that heat into those over-unity photons.
This cooling effect has some interesting implications for low-power
electronics, but most importantly, we can all rest just a little bit
easier knowing that the basic physical rules that frame our perception
of the universe have survived for one more day.
Source : http://dvice.com
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