# Is op amp or any amplifier circuit/device a over-unity device?

 P: 92 Is op amp or any amplifier circuit/device a over-unity efficient device? The above question has been stuck in my mind, and I can't figure it out, as Vout is greater than Vin which Pin>Pout. So is it? I heard alot about free energy and aether, thus come to this question.
 P: 3,898 Do you mean over 100% efficiency? Absolutely not. If there is one, I want one too!!! Or are you just talking about voltage gain?
 P: 92 the efficiency. So how to calculate its efficiency, if it is not Vout/Vin since it is voltage gain?
 P: 3,898 Is op amp or any amplifier circuit/device a over-unity device? I am confuse how do you define efficiency? I am confused. To me, efficiency means power out divid by power in times 100 percent. Nothing even come close to 100%. Power in include the driving power plus the power input from the power supplies.
 P: 92 So power in should be the Voltage IN while power out should be Voltage OUT? I am confused how to calculate it. Maybe although the voltage gain is high, the output current is very low? I do know that is true for transformers, but dunno for any opamp or semiconductor.
Mentor
P: 41,041
 Quote by Pagedown Is op amp or any amplifier circuit/device a over-unity efficient device? The above question has been stuck in my mind, and I can't figure it out, as Vout is greater than Vin which Pin>Pout. So is it? I heard alot about free energy and aether, thus come to this question.
I will put this as gently as I can.

The big giant battery or the wall power plug is where the "extra" energy comes from for power amplifiers. There is no free energy.