# Apparent Power (Ckrts 2)

Discussion in 'Homework Help' started by John Ramelb, May 10, 2014.

1. ### John Ramelb Thread Starter New Member

Feb 2, 2014
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0
Hello Good day Engrs.

Can someone please explain to me why do I need to conjugate the Current in Complex form or Polar form, to get the value of the apparent power. What is the main reason why I need to Conjugate the current in apparent power. Thanks

2. ### WBahn Moderator

Mar 31, 2012
23,859
7,383
You don't. The apparent power is the magnitude of the voltage phasor and the current phasor and is independent of the angle between the two, so it doesn't matter whether you conjugate it or not since you are going to lose that information in the process of finding apparent power.

Now, if you want to know why you conjugate the current to get complex power, that's a different story.

In terms of the RMS magnitudes of the voltage and current and the phase angles of each, what is the expression for the real power and what is the expression for the reactive power?