Concept:Rectification relies on asymmetric conduction: conducting current with low resistance in one polarity while presenting high resistance in the opposite polarity.
Formula:$$R_{\text{forward}} \ll R_{\text{reverse}} \implies I_{\text{forward}} \gg I_{\text{reverse}}$$
Solution:- Under forward bias (\( V > V_{\text{barrier}} \)), the diode has low dynamic resistance (a few ohms) and conducts readily.
- Under reverse bias, the diode presents high resistance (mega-ohms), blocking current flow.
- This directional behavior enables the diode to pass only one half-cycle of an AC waveform, producing a DC output.
Why other options are incorrect:- Option A: A linear, symmetrical resistance represents an ohmic resistor, which cannot rectify alternating current.
- Option B: Light emission is a characteristic of forward-biased light emitting diodes (LEDs), not the mechanism of rectification.
- Option D: Negative differential resistance is a specialized property of tunnel or Gunn diodes, not standard rectifiers.
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