## Sinusoidal sources and complex power

When calculating power in a given circuit, why is the complex conjugate of the current used to compute power?

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darbitman,

 When calculating power in a given circuit,
You mean apparent power, don't you?

 why is the complex conjugate of the current used to compute power?
Easy, the apparent power is I^2 multiplied by Z, which equals I* times I times Z, which equals I* times V. I* is the conjugate of I, I^2 = I times I*, and I times Z = V .

Ratch

 Quote by Ratch darbitman, You mean apparent power, don't you? Easy, the apparent power is I^2 multiplied by Z, which equals I* times I times Z, which equals I* times V. I* is the conjugate of I, I^2 = I times I*, and I times Z = V . Ratch
I meant apparent power, sorry. And thank you for the explanation.