Electronic Devices — Easy Practice (Set 2) — JEE Main 2027 Physics Notes

Quick Recap — Junction, Diode & Gates

p-n junction: a depletion region with a barrier potential ( $\approx 0.7$ V for silicon, $\approx 0.3$ V for germanium).
Bias: forward (p-side to $+$ ) conducts and the depletion narrows; reverse (p-side to $-$ ) blocks and the depletion widens (only a tiny minority-carrier current flows).
Rectifier: half-wave (1 diode) or full-wave (2 or 4 diodes) converts AC to pulsating DC; a capacitor filters it.
Special diodes: LED (emits light in forward bias), photodiode (reverse bias, detects light), solar cell (photovoltaic), Zener (reverse breakdown, voltage regulator).
Logic gates: OR (any input 1), AND (all inputs 1), NOT (invert), NAND ( $\overline{A\cdot B}$ ), NOR ( $\overline{A+B}$ ).