ESE 121 Lecture Notes - Lecture 20: Thermionic Emission, Vacuum Tube, Fullerton, California
25 Apr 2017
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Document Summary
It simply states that energy cannot be created or destroyed. It also means that you can"t construct a device that will input a small amount of energy and magically output a large amount of energy: the best that any device can get is to 100% power. Energy can be transformed, however, and most devices transform some electric energy into heat energy reducing their efficiency below 100%. Perpetual motion machine: many people have tried to create a device that with more than 100% efficiency. In this case it would have to output more power than it took in. If this were the case, it could reroute some of its output to power itself and have a surplus of power left over. In essence we take the large amount of power in the dc external power supply or battery and transform it into a copy of the signal but with more power.
