PN junctions and diodes

In a forward-biased PN junction, which capacitance arises from the storage of injected minority carriers?

  1. ADiffusion capacitance
  2. BJunction (depletion) capacitance
  3. CWiring capacitance
Show answer and explanation

Answer: A. Diffusion capacitance

Under forward bias, minority carriers are injected and stored on both sides of the junction, and their amount changes with voltage, so they act as a capacitance. This is the diffusion capacitance, which grows with forward current. Under reverse bias, the junction capacitance of the depletion layer dominates.

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