Physics Electronics PMDC Conceptual Practice
PMDC Verified Question 79 of 494
In a 4-diode full-wave bridge rectifier, how many diodes conduct simultaneously during any single half-cycle of the AC input voltage?
A
1 diode
B
4 diodes
C
3 diodes
D
2 diodes
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: 2 diodes
Concept:

A bridge rectifier operates by conducting through diagonally opposite pairs of diodes in each half-cycle.

Formula:

Qualitative concept / No formula required.

Solution:

  • During the positive half-cycle, diodes \( D_1 \) and \( D_3 \) are forward biased and conduct in series with the load resistor.


  • During the negative half-cycle, diodes \( D_2 \) and \( D_4 \) conduct in series with the load resistor.


  • Thus, exactly 2 diodes conduct simultaneously at any given time.


Why other options are incorrect:

  • Option A: Single-diode conduction occurs only in half-wave rectifiers.


  • Option B: All 4 diodes cannot conduct at the same time without short-circuiting the transformer secondary.


  • Option C: Three diodes never conduct simultaneously in a balanced bridge.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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