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. The reverse saturation current is nearly constant with voltage (until breakdown), determined by the minority carrier concentration, not the applied reverse voltage magnitude. Substituting values gives Nearly independent of voltage, which matches expected behaviour for this semiconductor device configuration, confirming doping, depletion and rectifier principles.