# Importance of phase angles when analysing AC circuit

Freshmen EE circuit. Resistance, inductivity, capacitance are given and effective value of voltage. No phase angles are given.

When calculating complex power, may I assume the phase angle of the voltage source? Current should adjust accordingly and give me the same power no matter which angle I assume.

Am I right? (I know there are formulas with effective U)

• You may assume either current or voltage as the reference zero degrees. Current is the better choice for series connected components, and voltage for parallel. The choice sometimes makes the maths a bit easier. – Chu Aug 31 '15 at 12:34