Physics Electronics PMDC Conceptual Practice
PMDC Verified Question 368 of 494
In an ideal half-wave rectifier circuit with an input peak voltage of \( V_m \), what is the voltage across the load resistor during the negative half-cycle?
A
\( -V_m \)
B
\( 0\text{ V} \)
C
\( +V_m \)
D
\( \frac{V_m}{\sqrt{2}} \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: \( 0\text{ V} \)
Concept:

During the negative half-cycle, an ideal diode is reverse-biased, acting as an open circuit with zero current through the load.

Formula:

$$V_L = I_L R_L = (0\text{ A}) \times R_L = 0\text{ V}$$

Solution:

  • During the negative half-cycle, the diode is reverse-biased and presents infinite resistance (\( R_{\text{diode}} = \infty \)).


  • Because the circuit is open, current through the load resistor is zero (\( I_L = 0\text{ A} \)).


  • Applying Ohm's law gives a load voltage of \( V_L = I_L R_L = 0\text{ V} \).


  • The full peak input voltage \( V_m \) appears across the reverse-biased diode.


Why other options are incorrect:

  • Option A: \( -V_m \) appears across the reverse-biased diode as its peak inverse voltage, not across the load resistor.
  • Options C & D: Positive voltages appear across the load during forward conduction in the positive half-cycle, not during the negative half-cycle.

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