# How to Calculate Power Efficiency of an Amplifier in LTSpice

#### specs365

Joined Mar 14, 2019
29
HI, so I built the circuit povided below. I am quite new at amplifiers still. I am not sure how to calculate the power efficiency of the circuit, I can get the output power, but what sources etc do I take into account to get the input power? Do I have to check the power dissipated by each component somehow?

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#### Bordodynov

Joined May 20, 2015
2,604
See

#### specs365

Joined Mar 14, 2019
29
Really appreciate this, Thanks

#### ci139

Joined Jul 11, 2016
1,463
$?\ ...\ \eta=\frac{P_{LOAD}}{P_{TOTAL}}$
but further if the load ? speaker is not power efficient . . . then the energy to sound "adds up" by the spectral efficiency of the loudspeaker combined with atmospheric parameters
( https://en.wikipedia.org/wiki/Sound_pressure#Sound_pressure_level , https://en.wikipedia.org/wiki/Sound_intensity )
( https://www.sweetwater.com/insync/effects-of-temperature-humidity-live-sound/ )

#### specs365

Joined Mar 14, 2019
29
Do you mind if I ask for the .asc of this? Just so I can use it for future circuits too?

#### Bordodynov

Joined May 20, 2015
2,604
Take the electronic circuit

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#### specs365

Joined Mar 14, 2019
29
Thanks!