Form factor and peak factor of rectifier
The peak factor is defined as the ratio of the maximum value to the RMS value of an alternating quantity.
Peak factor = Peak value / RMS value
RMS voltage of a half wave rectifier, VRMS = Vm/2. Where Vm is the Maximum or peak voltage.
Then the Peak factor of a half wave rectifier can be calculated as,
Vm / VRMS = Vm / ( Vm / 2 ) = 2 Vm / Vm = 2
Similarly, For a full wave rectifier, the RMS voltage VRMS = Vm / √2
Therefore, the Peak factor value of a full wave rectifier = Vm / Vm/ √2
= Vm √2 / Vm = √2 = 1.414
The ratio of RMS value to the average value of an alternating quantity is known as its form factor.
Form factor = RMS value / Average value
RMS voltage of a half wave rectifier, VRMS = Vm / 2 and Average Voltage VAVG= Vm/π, Vm is the peak voltage.
Form factor of a half wave rectifier = VRMS / VAVG = ( Vm /2 ) / ( Vm / π )
= π Vm / 2 Vm = 1.57
For a full wave rectifier, the RMS voltage VRMS = Vm / √2 and the average Voltage,
VAVG = 2 Vm / π
Form factor value of a full wave rectifier = ( Vm / √ 2 ) / ( 2Vm / π )
= π Vm / 2√2 Vm = 1.11