Physics · Class 12 · Chapter 14
Semiconductor Electronics: Materials, Devices and Simple Circuits
12 lessons 95 min 2 simulations
Why does silicon sit between copper and glass in how well it conducts, and how can a few impurity atoms per million change that a thousandfold? This chapter explains conduction with energy bands, builds n-type and p-type material by doping, joins them into a p-n junction, and follows the junction diode from its one-way V-I curve to the rectifier and capacitor filter inside every mains power supply.
What the exam asks
NEET asks for the band-gap ranges (insulator above 3 eV, C 5.4 eV, Si 1.1 eV, Ge 0.7 eV), which dopants make n-type and p-type material and which carriers are the majority, the law nₑnₕ = nᵢ² with Example 14.2's numbers, what happens to the barrier and depletion layer under forward and reverse bias, the cut-in voltages (0.7 V Si, 0.2 V Ge), dynamic resistance, and the output frequency of half-wave and full-wave rectifiers. Marks are lost by calling doped material charged, by mixing up diffusion and drift currents, and by giving a full-wave rectifier the input frequency.
Lessons
12 lessons · 95 min
1From valves to semiconductorsNCERT §14.16 min2Classifying solids by conductivityNCERT §14.26 min3Energy bandsNCERT §14.27 min4Intrinsic semiconductorsNCERT §14.37 min5n-type and p-type semiconductorsNCERT §14.47 min6Carrier concentration and band levelsNCERT §14.48 min7Formation of a p-n junctionNCERT §14.5.17 min8Diode under forward and reverse biasNCERT §14.67 min9Diode V-I characteristicsNCERT §14.6.210 min 1 sim10Half-wave and full-wave rectifiersNCERT §14.710 min 1 sim11Filtering with a capacitorNCERT §14.76 min12Chapter reviewMust-know facts, traps and formulas14 min