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

A full-wave rectifier circuit converts alternating current (AC) to direct current (DC). It allows both halves of the AC waveform to contribute to the output current. This is achieved by inverting the negative half of the AC cycle. As a result, the output frequency of a full-wave rectifier is double the mains frequency. Given:

Mains Frequency = \(50\) Hz

In a full-wave rectifier, every cycle of the AC input contributes two cycles of ripple. Thus, the fundamental frequency in the ripple output is doubled:

Ripple Frequency = \(2 \times \text{Mains Frequency} = 2 \times 50 \text{ Hz} = 100 \text{ Hz}\)

Therefore, the fundamental frequency in the ripple output is \(100\) Hz.

Answer 2

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.