Ripple factor is important for a good rectifier

The direct current (DC) produced by a half wave rectifier is not a pure DC but a pulsating DC. In the output pulsating DC signal, we find ripples. These ripples in the output DC signal can be reduced by using filters such capacitors and inductors.

In order to measure how much ripples are there in the output DC signal we use a factor known as ripple factor. The ripple factor is denoted by γ.

The ripple factor tells us the amount of ripples present in the output DC signal.

A large ripple factor indicates a high pulsating DC signal while a low ripple factor indicates a low pulsating DC signal.

If the ripple factor is very low then it indicates that the output DC current is closer to the pure DC current. In simple words, the lower the ripple factor the smoother the output DC signal.

Ripple factor can be mathematically defined as the ratio of rms value of AC component of the output voltage to the DC component of the output voltage.

Ripples factor = rms value of AC component of the output voltage / DC component of the output voltage

Where, rms = root mean square

or

The ripple factor is also simply defined as the ratio of ripple voltage to the DC voltage

Ripple factor  = Ratio of ripple voltage / DC voltage

This factor is very important parameter for assessing the effectiveness of the rectifier. The lower ripple factor value shows that the ripples in the DC output is less and the efficiency of the rectifier is better. and, the higher value shows that there are more fluctuating ac component present in the rectified output.

The ripple factor should be kept as minimum as possible to construct a good rectifier.