Physics Electronics PMDC Conceptual Practice
PMDC Verified Question 11 of 494
If an AC input voltage of frequency \(f = 50\text{ Hz}\) is supplied to a full-wave rectifier, what is the fundamental frequency of the output ripple?
A
\(25\text{ Hz}\)
B
\(50\text{ Hz}\)
C
\(100\text{ Hz}\)
D
\(200\text{ Hz}\)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: \(100\text{ Hz}\)
Concept:

A full-wave rectifier converts both the positive and negative halves of each input AC cycle into positive output pulses. Thus, for every complete input cycle, two output pulses are generated, doubling the ripple frequency.

Formula:

$$f_{\text{ripple, FW}} = 2 f_{\text{in}}$$

$$\text{whereas } f_{\text{ripple, HW}} = f_{\text{in}}$$

Solution:

  • Given input AC frequency: \(f_{\text{in}} = 50\text{ Hz}\).


  • For a full-wave rectifier:


  • $$f_{\text{ripple}} = 2 \times 50\text{ Hz} = 100\text{ Hz}$$


Why other options are incorrect:

  • Option A: \(25\text{ Hz}\) would imply halving the frequency, which does not occur in rectification.
  • Option B: \(50\text{ Hz}\) is the ripple frequency for a half-wave rectifier (\(f_{\text{ripple}} = f_{\text{in}}\)).
  • Option D: \(200\text{ Hz}\) corresponds to a quadrupled frequency, which is not produced by standard single-phase full-wave circuits.

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