Sinusoidal sources and complex power

[d.arbitman]

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

 

[Ratch]

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

 

[d.arbitman]

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.