## Ripple Factor of bridge rectifier

The pulsating output of a rectifier can be considered to contain a dc component and ac component called the ripples. The ripple current is undesirable and its value should be the smallest possible in order to make the rectifier effective.

The ripple voltage or current is measured in turn of the ripple factor which is defined as the ratio of the effective value of the ac components of voltage (or current) present in the output from the rectified to the direct or average value of the output voltage (or current)

The effective value of the load current is given as

I2 = Idc2 + I12 + I22 + I42 + ……=Idc2 + Iac2

Where I1, I2, I4 etc. are the rms values of fundamental, second, fourth etc. harmonics and Iac2 is the sum of the square of the rms Value of the ac components.

So ripple factor, γ = Iac /Idc = √{(I2 + Idc2)/Idc} = √[{Irms/Idc}2 – 1] = √(Kf2 – 1)

Where Kf is the form factor of the input voltage. For half-wave rectifier, from factor is given as

Kf = Irms / Iav = (Imax/√2)/(2Imax / π) = π/2√2 = 1.11

Now, Ripple factor is given as

γ = √(Kf2 – 1) = √(1.112 – 1) = 0.482