Semiconductor Electronics Materials Devices and Simple Circuits - Notes, Topics, Formulas, Books, FAQs

Chapter 14 Class 12 Topics (NCERT Syllabus)

1. Introduction

Vacuum tubes were once used for controlling electron flow, but they were bulky and inefficient. Semiconductors revolutionised electronics by allowing control of charge carriers within solids. This led to compact, reliable, and low-power devices like diodes and transistors, which form the foundation of modern electronics.

2. Classification of Metals, Conductors, and Semiconductors

• Classification of solids on the basis of Band theory

3. Intrinsic Semiconductor

• Types Of Semiconductor

4. Extrinsic Semiconductor

1. n-type semiconductor: formed by doping with pentavalent impurities (e.g., P, As). Extra electrons act as majority carriers.
2. p-type semiconductor: formed by doping with trivalent impurities (e.g., B, Al). Holes act as majority carriers.

• Extrinsic Semiconductors

5. P-N Junction

A p–n junction is formed when a p-type semiconductor and an n-type semiconductor are joined together. At the junction, electrons from the n-side diffuse into the p-side, and holes from the p-side diffuse into the n-side, creating a region called the depletion region, which has immobile ions but no free charge carriers.

This region develops a built-in potential barrier that opposes further movement of carriers. The behavior of the junction under forward and reverse bias makes it the basic building block of many semiconductor devices like diodes, transistors, LEDs, and solar cells.

• P-N Junction

6. Semiconductor Diode

A semiconductor diode is a device formed by a $\mathbf{p}-\mathbf{n}$ junction with two terminals - anode ( $\mathbf{p}$-side) and cathode ( $\mathbf{n}$-side). It allows current to flow easily in one direction (forward bias) and blocks it in the opposite direction (reverse bias).

In forward bias, the potential barrier decreases, and current flows through the diode. In reverse bias, the barrier increases, and only a very small leakage current flows. Because of this property, diodes are widely used for rectification (converting AC to DC) and in many electronic circuits.

• Semiconductor Diode
• Diode

7. Application of Junction Diode as a Rectifier

A junction diode is commonly used as a rectifier, which converts alternating current (AC) into direct current (DC).

1. In half-wave rectification, the diode allows current to pass only during the positive half of the AC cycle, blocking the negative half.
2. In full-wave rectification, using either a center-tap transformer or a bridge circuit, both halves of the AC cycle are used to produce a smoother DC output.

• P-N Junction As A Rectifier

Semiconductor Electronics: Real Life Application

Diode in Chargers – The diode in your mobile charger allows current to flow only in one direction, converting AC from the wall into DC for your phone.

LEDs (Light Emitting Diodes) – Used in display screens, indicator lights, and decorative lighting.

Transistors in Amplifiers – Found in music systems, microphones, and speakers to amplify weak signals.

Solar Panels – Made of semiconductor materials like silicon, converting sunlight into electric current.

Computers and Smartphones – CPUs, memory chips, and other integrated circuits are made from semiconductors, enabling all digital processing.

Exam-wise Weightage of Semiconductor Electronics

Approach to Solve Electronic Devices Questions.

• Remember the diagrams for all the configurations like pnp, npn semiconductors, CE, CB, CC configurations to solve questions easily.

• Remember the directions of collector, base, emitter currents in different configurations so that you don’t get confused while solving questions.

• Try to remember all the formulas present in this chapter and you will be able to master those by practicing questions.

• Practice the diagrams of different logic gates and their truth tables and implementation of these gates using transistors.

Electronic Devices Tips

1. This is much theory-based topic, very few types of numerical can be created from this chapter.

2. Try to cover numerical from P-n junction diode, V-I characteristics, Zener diode, Transistors and Logic gates.

3. Make a plan to prepare for this chapter and stick to a Timetable.

4. Study the concept first and then start solving Electronic devices questions. Don't go through question directly without knowing the concept.

5. Solve previous year question of various exam from this chapter.

6. Use smart methods to solve questions.

Electronic Devices Books

For Electronic devices, chapter concepts in NCERT are enough but you will have to practice lots of questions including previous year questions and you can follow other standard books available for competitive exam preparation like Concepts of Physics (H. C. Verma) and Understanding Physics by D. C. Pandey (Arihant Publications).

NCERT Exemplar Solutions Subject wise link:

• NCERT exemplar solutions for class 11 Physics.
• NCERT exemplar solutions for class 11 Chemistry.
• NCERT exemplar solutions for class 11 Mathematics.
• NCERT exemplar solutions for class 11 Biology.

Related Topics,

NCERT Solutions Subject wise link:

• NCERT solutions for class 11 Physics.
• NCERT solutions for class 11 Chemistry.
• NCERT solutions for class 11 Mathematics.
• NCERT solutions for class 11 Biology.

NCERT Notes Subject Wise Link:

• NCERT notes Class 11 Maths
• NCERT notes Class 11 Physics
• NCERT notes Class 11 Chemistry
• NCERT notes Class 11 Biology