11.4 Apparent Power and
Power Factor (1)
Apparent Power, S, is the product of the r.m.s. values of
voltage and current.
It is measured in volt-amperes or VA to distinguish it from
the average or real power which is measured in watts.
Power factor is the cosine of the phase difference between
the voltage and current. It is also the cosine of the angle
of the load impedance.