Power-added efficiency (PAE) is a metric for rating the

efficiency Efficiency is the often measurable ability to avoid wasting materials, energy, efforts, money, and time in doing something or in producing a desired result. In a more general sense, it is the ability to do things well, successfully, and without ...

of a

power amplifier An audio power amplifier (or power amp) is an electronic amplifier that amplifies low-power electronic audio signals, such as the signal from a radio receiver or an electric guitar pickup, to a level that is high enough for driving loudspea ...

that takes into account the effect of the gain of the

amplifier An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It may increase the power significantly, or its main effect may be to boost the v ...

. It is calculated (in percent) as:

\mathrm = 100 \times \frac

It differs from most power efficiency descriptions calculated (in percent) as:

\eta = 100 \times  / {P_{IN}^{DC

PAE will be very similar to

when the gain of the amplifier is sufficiently high. But if the amplifier gain is relatively low the amount of power that is needed to drive the input of the amplifier should be considered in a metric that measures the efficiency of said amplifier.

References

* http://www.maxim-ic.com/glossary/index.cfm/Ac/V/ID/1010/Tm/power-added-efficiency-PAE * http://www.microwaves101.com/encyclopedia/efficiency.cfm Electronic amplifiers