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Electronic Devices

Energy bands in conductors, semiconductors and insulators (qualitative ideas only) Semiconductor diode – I-V characteristics in forward and reverse bias, diode as a rectifier;
Special purpose p-n junction diodes: LED, photodiode, solar cell and Zener diode and their characteristics, zener diode as a voltage regulator.
Junction transistor, transistor action, characteristics of a transistor and transistor as an amplifier (common emitter configuration), basic idea of analog and digital signals, Logic gates (OR, AND, NOT, NAND and NOR).

12th physics. NCERT notes

Transistor Action or Working of Transistor

A brief description of the three segments of a transistor is given below: Emitter: This is the segment on one side of the transistor....
12th physics. NCERT notes

Solar Cell

Solar cell A solar cell is basically a p-n junction which generates emf when solar radiation falls on the p-n junction. It works on the same...
12th physics. NCERT notes

Light Emitting Diode (LED)

Light Emitting Diode (LED) A light emitting diode (LED) is a forward biased PN junction diode, which emits visible light when energized. When a junction diode...
12th physics. NCERT notes

Logic Gates

Logic gates A gate is a digital circuit that follows curtain logical relationship between the input and output voltages. Therefore, they are generally known as...
12th physics. NCERT notes

Intrinsic Semiconductor

A semiconductor which is pure and contains no impurity is known as an intrinsic semiconductor. In an intrinsic semiconductor, the number of free electrons...
12th physics. NCERT notes

Energy band in solids

In solids, the atoms are arranged in a systematic space lattice and each atom is influenced by neighbouring atoms. The closeness of atoms results...
12th physics. NCERT notes

PN Junction Diode as a rectifier

Junction Diode as a rectifier The process in which alternating voltage or alternating current is converted into a direct voltage or direct current is known...
12th physics. NCERT notes

Transistor as an Amplifier

Transistor as an Amplifier Amplification is the process of linearly increasing the amplitude of an electrical signal. A transistor can act as an amplifier directly...
12th physics. NCERT notes


Photodiode A photodiode is again a special purpose p-n junction diode fabricated with a transparent window to allow light to fall on the diode....
12th physics. NCERT notes

Energy bands in conductors

The lower completely filled band is called valence band and the upper empty band is called conduction band. The gap between the top of...