Electronic Circuits 1: Introduction to Electronics and Semiconductor Physics

Jul 21, 2024

Electronic Circuits 1: Introduction

Instructor: Behzad Razavi

Course Goals

  • Build a foundation for the analysis and design of electronic circuits.
    • Focus: Introduction to electronics and semiconductor physics.

Key Topics Covered

Basic Circuit Theory Recap

  • Circuit Theorems: KVl, KCl, Norton Equivalent, Thevenin Equivalent.
  • Components: Resistors, capacitors, inductors, transformers.
  • Limited applications due to the small number of simple components.

Introduction to Electronics

  • Additional Components: Diodes, Transistors (Bipolar & MOS), Operational Amplifiers (Op-Amps).
    • Open up new opportunities for complex and useful circuits.

Semiconductor Physics

  • Importance: Essential to understanding how electronic devices operate.
  • Key Concepts from Physics and Chemistry: Atomic structure, electron movement, bonding, and energy levels.

Course Outline

  1. Semiconductor Physics: Foundation for all devices.
    • Go over the creation and properties of semiconductors.
  2. Diode Basics: Construction, working principles, and modeling.
    • Diode applications and circuits.
  3. Transistor Basics: Bipolar and MOS transistors, operational principles, and modeling.
    • Circuit design involving these transistors.
  4. Op-Amp Basics: Operational principles and applications in circuits.
  5. Frontiers in Electronics: Real-life applications and examples.
    • E.g., overview of cell phone operation, transmitter-receiver principles.

Subjects in Semiconductor Physics (Intro)

  • Atomic Structure and Electronic Bonds: Understanding nucleus, electrons, and valence electrons.
    • Silicon's behavior due to its four valence electrons, forming a lattice or crystal structure.
  • Silicon Crystal and Conduction: Behavior at absolute zero vs. finite temperature.
    • Presence of free electrons contributing to current conduction.
  • Important Equations: Density of free electrons depends on temperature and material (e.g., silicon, germanium).

Charge Carriers

  • Basic Principles: Electrons and holes as charge carriers, movement mechanism.
  • Conduction Mechanism: How holes and electrons contribute differently to conduction.
    • Electrons are generally faster than holes due to the release and trap mechanism in holes.

Important Concepts:

  • Energy Bandgap: Different for various materials (e.g., silicon vs. germanium).
  • Intrinsic vs. Extrinsic Silicon: Concepts of pure and doped silicon.
    • Doping with phosphorus (donor atoms) to increase conductivity.
    • Carrier Density Modification: Changing number of free electrons and holes in silicon.
    • Doping Levels: Lightly vs. heavily doped silicon and the impact on free electron density.
    • Maintaining Charge Balance: Product of electron and hole densities remains constant.

Understanding Electronics Through Examples

  • Cell Phone Example: Basic transmitter and receiver principles.
    • Antenna, amplifier, modulator, carrier signal, oscillator, power amplifier, low noise amplifier are key components.

Next Steps

  • Dive deeper into semiconductor physics and corresponding applications in electronic circuits.
  • Further explore practical applications to understand the relevance to daily life.