Ripple Factor Formula
What is Ripple Factor ?
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.
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 of Half-wave Rectifier
In half-wave rectification,
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,
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.