AC Power

As in the case with DC power, the instantaneous electric power in an AC circuit is given by P = VI, but these quantities are continuously varying. Almost always the desired power in an AC circuit is the average power, which is given by

P_avg = VI cosφ

where φ is the phase angle between the current and the voltage and where V and I are understood to be the effective or rms values of the voltage and current. The term cos φ is called the "power factor" for the circuit.

RLC series circuit details

For C = μF and L = mH and resistance R =  ohms

at angular frequency ω =  x10^ rad/s,

frequency f = x10^ Hz =  kHz =  MHz

the impedance is

Z =  x10^ ohms at phase φ =  degrees.

For an applied rms voltage V = volts,
the rms current will be I =  x 10^ amperes.

and the AC power is given by Pavg = VI cosφ =  watts

The power factor is cos φ =

so the power is reduced to that fraction of what it would be in a DC circuit with the same voltage and current.

Default values will be entered for unspecified parameters, but all component values can be changed. Click outside the box after entering data to initiate the calculation.