Apparent Power, S - appears on the hypotenuse of the power triangle.
Apparent power is given by:
Apparent power = V I
= Voltage * Current
Units are volt -amps (VA)
True Power, P - appears on the adjacent of the power triangle
True power is given by:
I2R = S cos f = VI cos f
This is the power in the resistive part of the circuit
Units are Watts (W)
Reactive Power, Q - appears on the opposite of the power triangle
Given by:
I2XL = S sin f = VI sin f
and: I2XC = S sin f = VI sin f
where XL and XC are inductive reactance and capacitive reactance respectively, and f is the phase angle.
Units are volt-amps reactive (VAr)
Power Factor:
Power Factor = True Power / Apparent Power = P / S = cos f
True Power = Apparent Power * Power Factor
= VI cos f
