(i) Energy bands in solids; energy band diagrams for distinction between conductors, insulators and semi-conductors - intrinsic and extrinsic; electrons and holes in semiconductors.
(ii) Junction diode; depletion region; forward and reverse biasing, V-I characteristics; half wave and a full wave rectifier; solar cell, LED and photodiode. Zener diode.
(iii) Junction transistor; npn and pnp transistors; current gain in a transistor and transistor as an amplifier in common emitter mode (only circuit diagram and qualitative treatment); transistor as a switch; oscillator.
(iv) Elementary idea of discreet and integrated circuits, analogue and digital signals. Logic gates (symbols; working with truth tables; applications and uses) - NOT, OR, AND, NOR, NAND. Combination of gates.