Ideal rectifier performance criteria Which set of characteristics best describes an ideal rectifier and its output quality?

Difficulty: Easy

Correct Answer: 100% efficiency, zero ripple factor, zero harmonic factor, unity displacement factor

Explanation:


Introduction / Context:
An ideal rectifier converts AC to DC with perfect effectiveness and produces a pure DC output with no AC components (harmonics). Understanding these ideal metrics helps benchmark practical rectifiers and assess filters and power-factor correction requirements.


Given Data / Assumptions:

  • Idealized conversion (no losses, no device drops).
  • Pure DC output (no ripple, no AC harmonics).
  • Unity displacement factor (current in-phase with voltage).


Concept / Approach:

Efficiency is output DC power divided by input power; in the ideal case, it is 100%. Ripple factor measures the AC component relative to DC; for an ideal DC output, it is zero. Harmonic factor quantifies distortion components; with a pure DC output, it is zero. Displacement factor is the cosine of the phase angle between fundamental current and voltage; with perfect in-phase operation, it is unity.


Step-by-Step Solution:

Define efficiency: η = P_out / P_in → 1.0 ideally.Define ripple factor: rf = I_ac,rms / I_dc → 0 for pure DC.Harmonic factor: based on harmonic RMS relative to fundamental → 0 if no harmonics.Displacement factor: cos φ → 1 when φ = 0°.


Verification / Alternative check:

Any nonzero ripple or harmonic immediately contradicts the ideal definition; any phase displacement lowers the displacement factor below unity.


Why Other Options Are Wrong:

Unity ripple factor means significant AC content; unity harmonic factor is non-ideal; zero displacement factor implies 90° phase shift, not acceptable for ideal conversion.


Common Pitfalls:

Confusing ripple factor with power factor; overlooking that practical rectifiers always have some ripple and distortion unless perfectly filtered.


Final Answer:

100% efficiency, zero ripple factor, zero harmonic factor, unity displacement factor

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