Practice question

**Diode characteristics** forward bias reduces barrier, width of depletion region decreases, resistance low ~10-100 Ω, current primarily due to majority diffusion, exponential I = I_s(e^{eV/kT}-1), reverse bias widens depletion region, resistance high ~MΩ, dominant current drift due to minority carriers, reverse saturation current small μA-nA, typically 10⁻⁶ A, increases sharply at breakdown Zener/avalanche. A p-n junction diode allows current in forward bias (low resistance) and blocks it in reverse bias (high resistance), making it ideal for rectification of AC to DC. Substituting values gives Rectify alternating current, which matches expected behaviour for this semiconductor device configuration, confirming doping, depletion and rectifier principles.