Physics Electronics PMDC Conceptual Practice
PMDC Verified Question 351 of 494
An input \( \text{AC} \) supply of \( 60\text{ Hz} \) is connected to a full-wave bridge rectifier. What is the fundamental output ripple frequency?
A
\( 30\text{ Hz} \)
B
\( 60\text{ Hz} \)
C
\( 90\text{ Hz} \)
D
\( 120\text{ Hz} \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: \( 120\text{ Hz} \)
Concept:

A full-wave rectifier rectifies both half-cycles of the input \( \text{AC} \) waveform into positive output pulses, doubling the output pulse repetition rate relative to the input line frequency.

Formula:

$$f_{\text{out}} = 2 \times f_{\text{in}}$$

Solution:

  • Given input frequency: \( f_{\text{in}} = 60\text{ Hz} \).


  • For a full-wave rectifier: \( f_{\text{out}} = 2 \times 60\text{ Hz} = 120\text{ Hz} \).


  • The load receives two output pulses per input cycle period \( T = \frac{1}{60}\text{ s} \).


Why other options are incorrect:

  • Option A: \( 30\text{ Hz} \) is half the input frequency, which would indicate subharmonic frequency division.
  • Option B: \( 60\text{ Hz} \) is the output ripple frequency of a half-wave rectifier, not a full-wave rectifier.
  • Option C: \( 90\text{ Hz} \) is an incorrect multiple (\( 1.5 f_{\text{in}} \)).

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