Question

In a full wave rectifier circuit operating with \(50\,\text{Hz}\) mains frequency, the fundamental frequency in the ripple at the output would be

• A. \(25\,\text{Hz}\)
• B. \(50\,\text{Hz}\)
• C. \(75\,\text{Hz}\)
• D. \(100\,\text{Hz}\)

Hint:

For rectifiers: Half-wave rectifier: \[ f_r=f \] Full-wave rectifier: \[ f_r=2f \] Thus, for \(50\,\text{Hz}\) AC mains: \[ \text{Half-wave ripple frequency}=50\,\text{Hz} \] \[ \text{Full-wave ripple frequency}=100\,\text{Hz} \]

Answer 1

The Correct Option is D

Concept: In a full-wave rectifier, both the positive and negative half-cycles of the AC input are converted into positive output pulses. Therefore, the ripple frequency is twice the input AC frequency.

Step 1: Write the relation for ripple frequency. \[ f_r=2f \] where \[ f_r=\text{ripple frequency} \] and \[ f=\text{input AC frequency} \]

Step 2: Substitute the given frequency. Given, \[ f=50\,\text{Hz} \] Therefore, \[ f_r=2\times50 \] \[ f_r=100\,\text{Hz} \]

Step 3: State the answer. \[ \boxed{ f_r=100\,\text{Hz} } \] Hence, the correct option is \[ \boxed{(D)} \]