Physics Electronics PMDC Conceptual Practice
PMDC Verified Question 269 of 494
If one of the two diodes in a center-tapped full-wave rectifier burns out and becomes an OPEN circuit, how will the output voltage across the load be affected?
A
The output becomes pure unrectified AC
B
The output voltage doubles in magnitude
C
The output drops to zero across the entire cycle
D
The circuit behaves as a half-wave rectifier, delivering power during only one half-cycle
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: The circuit behaves as a half-wave rectifier, delivering power during only one half-cycle
Concept:

In a center-tapped full-wave rectifier, each diode handles one half-cycle independently. If one diode opens, the remaining diode continues to rectify its half-cycle, converting the circuit into a half-wave rectifier.

Formula:

$$\text{Normal: } f_{\text{ripple}} = 2 f_{\text{in}}, \ V_{\text{dc}} = \frac{2V_m}{\pi} \longrightarrow \text{One Diode Open: } f_{\text{ripple}} = f_{\text{in}}, \ V_{\text{dc}} = \frac{V_m}{\pi}$$

Solution:

  • The half-winding associated with the open diode cannot deliver current to the load.


  • The other half-winding and intact diode continue to supply current during their half-cycle.


  • Thus, the circuit operates as a half-wave rectifier.


Why other options are incorrect:

  • Option A: The single diode still rectifies its active half-cycle, producing pulsating DC rather than AC.
  • Option B: Output power and average DC voltage decrease by half.
  • Option C: The intact diode continues conducting on its half-cycle.

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