Examkin

Soru

Zorluk: ZorDiodes

An electronics technician is testing a power supply circuit featuring a four-diode full-wave bridge rectifier driven by a 60 Hz60\text{ Hz} AC secondary winding. During testing under load, one of the four rectifier diodes fails open. Which of the following best describes the electrical output observed across the load resistor?

  1. The circuit delivers pulsating DC with a ripple frequency of 60 Hz60\text{ Hz} because only one half-cycle path remains functional.Cevap
  2. B
    The circuit continues full-wave rectification at a 120 Hz120\text{ Hz} ripple frequency because the three remaining diodes reroute current through both alternations.
  3. C
    The output across the load reverts entirely to an alternating current (AC) waveform at 60 Hz60\text{ Hz}.
  4. D
    The output voltage and current drop completely to zero across the entire AC cycle due to an open circuit.

Cevap

The circuit operates as a half-wave rectifier, supplying pulsating DC with a ripple frequency of 60 Hz60\text{ Hz} because only one alternation pair conducts.
A standard bridge rectifier uses two diodes per half-cycle to route current through the load in the same direction. When one diode opens, the series loop for that half-cycle is broken, producing zero output during that alternation. The other pair continues to conduct normally during the opposite half-cycle, resulting in half-wave rectification where pulses occur once per AC period at 60 Hz60\text{ Hz}.

Adım Adım Çözüm

1
Analyze normal full-wave bridge rectifier conduction paths.
In normal operation, two diodes conduct in series on the positive half-cycle, and the opposite two diodes conduct in series on the negative half-cycle, yielding full-wave pulsating DC at twice the input line frequency (2×60 Hz=120 Hz2 \times 60\text{ Hz} = 120\text{ Hz}).
Understanding normal operation establishes the baseline for analyzing component failure.
2
Determine the impact of one diode failing open on both AC half-cycles.
The half-cycle requiring the open diode cannot complete its series loop, resulting in zero conduction during that alternation. The opposite half-cycle still has both diodes forward-biased and fully operational.
Diodes operate as one-way directional switches in specific series pairs per AC polarity.
3
Identify the resulting waveform characteristics across the load.
The circuit delivers unidirectional current pulses during only one half-cycle of the input AC sine wave, which defines half-wave rectification with a fundamental ripple frequency equal to the input line frequency (60 Hz60\text{ Hz}).
A single pulse per full AC cycle corresponds directly to the source frequency of 60 Hz.

Anahtar Kavram

Diode bridge rectification mechanics and single-diode open fault behavior
Tahmini Süre:1m 30s
Bu soruyu puanla

Konular

Diodes

Bu konudan daha fazla soru