Physics Electronics PMDC Conceptual Practice
PMDC Verified Question 68 of 494
Which of the following waveforms accurately represents the voltage output across the load resistor in a basic single-diode half-wave rectifier supplied with a sinusoidal AC input?

Rectified Output Waveform
A
Continuous bi-directional alternating sine wave
B
Constant, smooth, ripple-free horizontal line
C
Inverted continuous full-wave pulsating waveform
D
Unidirectional pulses separated by zero-voltage half-cycle intervals
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Unidirectional pulses separated by zero-voltage half-cycle intervals
Concept:

A single diode conducts only during the positive half-cycle when forward biased and blocks current during the negative half-cycle.

Formula:

$$v_o(t) = \begin{cases} V_m \sin(\omega t) & 0 \le \omega t < \pi \\ 0 & \pi \le \omega t < 2\pi \end{cases}$$

Solution:

  • During the positive half-cycle, the diode is forward biased and conducts, producing a half-sine output across the load.


  • During the negative half-cycle, the diode is reverse biased, cutting off current completely (\( V_{\text{load}} = 0 \)).


  • The resulting waveform consists of unidirectional pulses separated by zero-voltage gaps.


Why other options are incorrect:

  • Option A: Describes unrectified AC input.


  • Option B: Describes the output of a fully filtered and regulated DC power supply.


  • Option C: Describes full-wave rectification.

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