Question

A full-wave rectifier circuit is operating from 50 Hz mains, the fundamental frequency in the ripple output will be:

• A. \( 50 \) Hz
• B. \( 70.7 \) Hz
• C. \( 100 \) Hz
• D. \( 25 \) Hz

Hint:

In a full-wave rectifier, both halves of the AC waveform are converted into positive cycles. The frequency of the rectified output is always twice the input AC frequency: \[ f_{\text{ripple}} = 2 f_{\text{input}} \] This principle is crucial for understanding rectification and AC to DC conversion in circuits.

Answer 1

The Correct Option is C

Step 1: Understanding Full-Wave Rectification In an AC supply, the input signal is sinusoidal with a fundamental frequency \( f_{\text{in}} \). A full-wave rectifier converts both halves of the AC waveform into positive cycles. This means that for each cycle of the input signal, the rectified output completes two cycles. 
Step 2: Determining the Ripple Frequency For a full-wave rectifier, the output frequency is given by: \[ f_{\text{ripple}} = 2 f_{\text{input}} \] Given: \[ f_{\text{input}} = 50 \text{ Hz} \] \[ f_{\text{ripple}} = 2 \times 50 = 100 \text{ Hz} \] 
Step 3: Evaluating the Options - 50 Hz (Incorrect): This is the input AC frequency, but in a full-wave rectifier, the output frequency doubles. 
- 70.7 Hz (Incorrect): This value is incorrect as it does not follow the rectification frequency relation. 
- 100 Hz (Correct): This is the correct ripple frequency as per the full-wave rectification principle. 
- 25 Hz (Incorrect): This is an unrelated frequency and does not match the rectification formula. 
Step 4: Conclusion Thus, the fundamental frequency in the ripple output of a full-wave rectifier operating at 50 Hz is \( 100 \) Hz.