Ripple Factor Formula

Ripple Factor Formula

What is Ripple Factor ?

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The output of a rectifier consists of a d.c. component as well as  an a.c. component which is also known as ripple.

This a.c. component is undesirable and accounts for the pulsations in the rectifier output.

The effectiveness of a rectifier depends upon the magnitude of a.c. component in the output. Hence the smaller this
component, the more effective is the rectifier.

The ratio of r.m.s. value of a.c. component to the d.c. component in the rectifier output is known as ripple factor i.e.

ripple factor formula

Therefore, ripple factor is very important in deciding the effectiveness of a rectifier. The smaller the ripple
factor, the lesser the effective a.c. component and hence more effective is the rectifier.

Derivation of Ripple Factor

 

By definition, the effective or r.m.s. value of total load current is given by :

 

 

 

Dividing throughout by Idc , we get,

ripple factor equations

 

 

 

 

Ripple Factor of  Half-wave Rectifier

In half-wave rectification,

Hence,

61

                                62

                                   63

Hence it is clear that a.c. component exceeds the d.c. component in the output of a half wave rectifier .It results more pulsation in the output. So half wave rectifier is ineffective for conversion of a.c into d.c.

Ripple Factor of  Full-wave Rectifier

In full-wave rectification,

64

65

66

67

It is clear that d.c. component exceeds the a.c. component in the output of a full wave rectifier .

This results in lesser pulsation in the output of a full wave rectifier as compared to a half wave rectifier .

Therefore, full-wave rectification is invariably used for conversion rectification.