# Form factor and peak factor of rectifier

##### Peak factor

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, V_{RMS} = V_{m}/2. Where V_{m} is the Maximum or peak voltage.

Then the** Peak factor of a half wave rectifier ** can be calculated as,

V_{m} / V_{RMS }= V_{m} / ( V_{m} / 2 ) = 2 V_{m} / V_{m} = 2

Similarly, For a full wave rectifier, the RMS voltage V_{RMS} = V_{m} / √2

Therefore, the** Peak factor value of a full wave rectifier = **V_{m} / V_{m}/ √2

= V_{m} √2 / V_{m} = √2 = 1.414

##### Form factor

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, V_{RMS} = V_{m} / 2 and Average Voltage V_{AVG}= V_{m}/π, V_{m }is the peak voltage.

**Form factor of a half wave rectifier** = V_{RMS }/ V_{AVG }= ( V_{m} /2 ) / ( _{Vm} / π )

= π V_{m} / 2 V_{m} = 1.57

For a full wave rectifier, the RMS voltage V_{RMS} = V_{m} / √2 and the average Voltage,

V_{AVG} = 2 V_{m }/ π

**Form factor value of a full wave rectifier = **( V_{m} / √ 2 ) / ( 2V_{m} / π )

= π V_{m} / 2√2 V_{m} = 1.11