Page 307 - Basic Electrical Engineering
P. 307
X is the opposition offered by the capacitor to the flow of current and is
c
called capacitive reactance.
Like an inductor, in a capacitor also the average power absorbed for a
complete cycle is zero. When voltage is applied, the capacitor starts getting
charged, energy gets stored in the capacitor in the form of electro-static field.
When the applied voltage starts falling from its maximum value, the energy
starts getting returned to the supply. This way, the power is absorbed from
and then returned to the supply source The net power absorbed by a pure
capacitor is zero. Since current leads the voltage by 90°, the power factor of
the circuit is
P.f = cosϕ = cos 90° = 0
The average or net power in a pure capacitor circuit can be calculated as
or,
Average power in a purely capacitive circuit,
P = 0 (3.11)
