ELECTRONICS — Rectifier topologies How many diodes are used in a single-phase full-wave bridge rectifier circuit?

Difficulty: Easy

Correct Answer: 4

Explanation:


Introduction / Context:
Rectifiers convert alternating current (AC) to direct current (DC). The most common full-wave design for single-phase supplies is the bridge rectifier. Knowing its diode count helps when designing power supplies or troubleshooting.



Given Data / Assumptions:

  • Topology: single-phase full-wave bridge (Graetz bridge).
  • Goal: full-wave rectification (both half-cycles used).
  • Ideal diodes assumed, no center-tapped transformer.



Concept / Approach:
A bridge rectifier uses four diodes arranged in a diamond so that for each AC half-cycle two diodes conduct and two are reverse-biased, steering current through the load in the same direction.



Step-by-Step Solution:
Draw the classic bridge: four diodes form a loop around the load.Positive half-cycle: one upper and one lower opposite diode conduct; load sees forward current.Negative half-cycle: the other pair conducts; current direction through the load remains the same.Thus, exactly 4 diodes are required.



Verification / Alternative check:
Compare with a center-tapped full-wave rectifier, which uses two diodes but requires a center-tapped transformer. Without a center tap, the bridge uses four diodes to achieve the same full-wave output.



Why Other Options Are Wrong:
2 — corresponds to a full-wave rectifier with a center-tapped transformer, not a bridge.3/6/8 — not standard counts for a single-phase bridge (three-phase bridges use six diodes).



Common Pitfalls:
Confusing diode count between center-tapped and bridge configurations; also forgetting the higher forward drop in a bridge (two diode drops in series each half-cycle).



Final Answer:
4

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