Physics Electronics PMDC Conceptual Practice
PMDC Verified Question 19 of 494
An alternating input voltage waveform given by \(v(t) = 250 \sin(100\pi t)\text{ volts}\) is applied across a half-wave rectifier. What is the 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 B: \(50\text{ Hz}\)
Concept:

For a half-wave rectifier, the output waveform repeats once every full cycle of the input AC waveform. Therefore, the ripple frequency equals the input supply frequency.

Formula:

$$v(t) = V_m \sin(\omega t) = V_m \sin(2\pi f t)$$

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

Solution:

  • Comparing \(v(t) = 250 \sin(100\pi t)\) with \(v(t) = V_m \sin(2\pi f t)\):


  • $$2\pi f = 100\pi \implies f = \frac{100\pi}{2\pi} = 50\text{ Hz}$$


  • For a half-wave rectifier:


  • $$f_{\text{ripple}} = f_{\text{in}} = 50\text{ Hz}$$


Why other options are incorrect:

  • Option A: \(25\text{ Hz}\) results from dividing the supply frequency by 2.
  • Option C: \(100\text{ Hz}\) would be the output ripple frequency if a full-wave rectifier were used.
  • Option D: \(200\text{ Hz}\) is an incorrect multiple.

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