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.