Lecture Notes on Basic Electronics

Basic Electronics Lecture Notes

University of Mines and Technology, Tarkwa

Faculty of Engineering

Department of Electrical and Electronic Engineering

Instructor: Solomon Nunoo

Table of Contents

Chapter 1: Introduction

1.1 Introduction

  • This course provides fundamental information about semiconductor devices and electronic circuits.

  • It is designed for students with no prior knowledge of electronics, beginning from the basics.

  • Familiarity with linear algebra and calculus is advantageous, as well as circuit analysis concepts like voltage, current, and resistance, Ohm’s Law, and Kirchhoff’s laws.

1.2 Why Study Basic Electronics

  • This discipline focuses on making informed choices in designing or modifying complex systems based on cost, reliability, and performance.

  • Decisions are generally based on estimates obtained from models of viable alternatives rather than direct experimental evaluation.

1.3 Course Objectives

  • To establish a solid foundation in the physics and design of semiconducting materials.

  • To cover understanding of solid-state electronic devices, including principles of operation, fabrication, and applications.

  • To make students comfortable with major semiconductor device characteristics and their application in circuits.

1.4 Prerequisite

  • No prior knowledge required; however, knowledge of linear algebra, calculus, and applied electricity will be beneficial.

1.5 Course Presentation and Assessment

  • 1.5.1 Course Presentation: Conducted through lectures with limited handouts.

  • 1.5.2 Tutorials & Assignments: Involve problem-solving to reinforce theory.

  • 1.5.3 Mode of Assessment:

    • Class participation - 10%

    • Quizzes/Assignments/ Labs - 30%

    • End of Semester Exams - 60%

  • 1.5.4 Course Assessment: Evaluated through a questionnaire at the end of the course, encouraging honest feedback.

1.6 Course Content

  1. Atomic Structure

  2. Semiconductor Theory

  3. PN Junction Diodes and Rectifier Circuits

  4. Bipolar Junction Transistors

  5. Field Effect Transistors

  6. Thyristors

1.7 Definitions

1.7.1 Electrical Classification of Solids

  • Semiconductor: A material with conductivity influenced by temperature, purity, and optical excitation, such as high-purity silicon.

    • Example: Near absolute zero, high-purity silicon behaves as an insulator; at room temperature, au ext{ (σ)} = 4 imes 10^{-6} ( ext{Ω-cm})^{-1}.

  • Insulator: A material with very low conductivity.

    • Example: At room temperature, au ext{ (σ)} = 10^{-12} - 10^{-14} ( ext{Ω-cm})^{-1}.

  • Conductor: A material with high conductivity.

    • Example: At room temperature, au ext{ (σ)} = 6 imes 10^{5} ( ext{Ω-cm})^{-1}.

1.7.2 Structure of Solid

  • Crystalline Solid: Three-dimensional periodic atom arrangement.

  • Polycrystalline Solid: Composed of misoriented small crystalline regions.

  • Amorphous Solid: Lacks a periodic structure.

1.7.3 Crystal Structure of Important Semiconductors

  • Diamond Lattice: Two interpenetrating face-centered cubic (fcc) lattices of the same material, each atom has 4 nearest neighbors.

  • Zincblende Lattice: Two interpenetrating fcc sub-lattices of different materials.

1.7.4 Semiconductor Physics

  • Electron: A negatively charged elementary particle.

  • Hole: The absence of an electron in a bond; equivalent to a positively charged mobile particle.

  • Intrinsic Semiconductor: Contains no impurities, having pure native material properties.

  • Extrinsic Semiconductor: Impurities modify electrical properties, often useful semiconductor elements (e.g., silicon, germanium).

1.7.5 Semiconductor Devices

  • Electronics: Science focused on electron behavior.

  • Diode: A two-terminal device enabling current to flow in one direction.

  • Transistor: A three-terminal device allowing voltage/current at one terminal to control behavior at others.

1.7.6 Photonic Relationships

  • Photon: A quantum of electromagnetic energy without mass or charge.

  • Laser Diode: Emits optical laser radiation when current is applied; closely relates to its bandgap properties.

1.8 Important Constants and Units

  • Electron Charge: q = 1.602 imes 10^{-19} ext{C}

  • Electron Mass: m = 9.109 imes 10^{-31} ext{kg}

  • Speed of Light: c = 2.998 imes 10^{8} ext{m/s}

1.9 Properties of Selected Semiconductors

  • Silicon (Si): Bandgap at RT: EG = 1.12 ext{eV}

  • Germanium (Ge): Bandgap at RT: EG = 0.67 ext{eV}

1.10 Reference Materials

  • Boylestad, R. and Nashelsky, L. (2013).

  • Floyd, T. L. (2012).

Chapter 2: Semiconductor Physics

2.1 Introduction

  • Focus on how electronic devices like diodes and transistors use semiconductive material principles.

  • Emphasizes the PN junction concept forming the basis for diodes and transistors.

2.2 The Atom

  • All matter comprises atoms (protons, neutrons, electrons).

  • Various atomic models (Bohr model and quantum model).

2.3 Materials Used in Electronics

2.3.1 Insulators, Conductors, and Semiconductors

  • Insulators have very few free electrons and high resistance. Examples include rubber and plastics.

  • Conductors have high free electron density; examples include copper and silver.

  • Semiconductors lie between insulators and conductors; controlled via doping with impurities.

2.3.2 Band Gap

  • The difference that must be overcome to move an electron from the valence band to the conduction band.

2.4 Current in Semiconductors

2.4.1 Conduction Electrons and Holes

  • Creation of electron-hole pairs through thermal excitation.

2.4.2 Electron and Hole Current

  • Net movement results in actual current conduction.

2.5 N-Type and P-Type Semiconductors

  • N-type: Conductivity primarily due to excess electrons (donor atoms).

  • P-type: Conductivity primarily due to holes (acceptor atoms).

2.6 The PN Junction

2.6.1 Formation of the Depletion Region

  • When n-type and p-type meet, charge carriers around the junction create a depletion layer.

2.6.2 Energy Diagrams of the PN Junction

  • Illustrative diagrams of energy levels in n-type and p-type semiconductors.

Chapter 3: Diodes and Applications

3.1 Introduction

  • Overview on diode operations and characteristics; underscoring the essential conduction directionality.

3.2 Diode Operation

3.2.1 The Diode

  • Common types and their structural representation. Basic principles regarding forward and reverse biasing.

3.2.2 Forward Bias

  • Conditions for increased current flow; dependence on bias polarity.

3.2.3 Reverse Bias

  • Conditions affecting current flow cessation and diode cut-off status.

3.3 Voltage-Current Characteristic of a Diode

3.3.1 V-I Characteristic for Forward Bias

  • Demonstrating current increase with biasing voltage surpassing the barrier potential.

3.3.2 V-I Characteristic for Reverse Bias

  • Illustrating minimal current flow until breakdown voltage is reached.

3.4 Diode Models

3.4.1 Bias Connections

  • Describing how forward and reverse bias conditions impact circuit analysis.

Chapter 4: Bipolar Junction Transistors

4.1 Introduction

  • Exploration of BJT technology and its applications.

4.2 BJT Structure

  • Structural design and its significance for operation.

4.3 Basic BJT Operation

4.3.1 Biasing

  • Significance of proper biasing for operation.

4.4 BJT Characteristics and Parameters

4.4.1 DC Beta (βDC) and DC Alpha (αDC)

  • Definitions and their importance for analyzing performance.

Further Chapters (5-6)

  • Continue with coverage of FETs, thyristors and additional semiconductor technologies per established course structure.