Electronics 101: Components And
Circuits


A motherboard showing a variety of electronics components.

Welcome to our course on circuit analysis and design!

Select a module to learn or continue below for more information:

This is a comprehensive, totally free course that guides learners toward mastery of fundamental electronics. Starting with electrical theory, it covers essential and helpful topics related to circuits and electronics all the way through advanced topics like semiconductors, analog circuits, and integrated circuits.

The goal of this course is to cover these complex topics in a gradual progression, from first principles onward. In terms of content, it spans materials that you might find in textbooks on electricity and electrostatics (Physics II in the US), electronics (Undergrad level), semiconductors, and analog circuits.

It is divided into modules that are grouped logically, from Electrical Theory to Analog Circuits.

We’re continually creating new content and updating the existing content.

Continue below for an outline of the course or jump right in using the button below.


Module 1 is an introduction to electrical theory that is designed for the complete electronics newbie while having enough interesting content even for professionals.

It covers what electricity is, and a brief history of electricity to help you understand it better. There’s a lesson on power generation and transmission, which covers how electricity gets to our homes and buildings.

The module then turns toward more technical topics. An overview of atomic structure is covered, which is then built upon in a lesson on electrical properties of materials. Module 1 is then rounded out with an overview of electric charge.

Module 2 – Fundamental Concepts:

Lesson 0: Module 2 Introduction

Lesson 1: Electric Circuits

Lesson 2: Electric Power Sources

Lesson 3: Electric Current

Lesson 4: Voltage

Lesson 5: Electrical Resistance

Lesson 6: Ohm’s Law

Lesson 7: Electric Power

Module 2 introduces the most important concepts in electrical and electronic systems. It begins with a lesson on electric circuits, which serve as the foundation for electrical and electronic systems.

The second lesson covers the first component needed in any circuit- the power source.

In electric current we see what happens when a power source is connected in a circuit and dive into why the electrons move in the first place, in voltage. Lesson 5 covers the important topic of electrical resistance. Next we combine the concepts covered in the three previous topics in order to tackle one of the most important equations in electronics: Ohm’s Law.

In the final lesson, we round out our coverage of fundamental concepts with a lesson on electric power.

Module 3 is longer than the previous modules, and tackles the essentials of direct current (DC) circuits.

Series and parallel circuits, as well as DC power sources are covered in the first few lessons.

Then we encounter the three basic building blocks of classical DC circuits: resistors, capacitors, and inductors.

The characteristics and usage of these components in series and parallel configurations, as well as specialized circuits like voltage dividers are covered, helping to provide context for how they are used in electronic systems.

In this module we also cover essential but somewhat more complex topics that are important to resistive circuit analysis, including Kirchoff’s Laws (KCL and KVL).

Module 4 – AC Circuits

Lesson 0: Module 4 Introduction

Lesson 1: Alternating Current

Lesson 2: AC Sources

Lesson 3: Impedance

Lesson 4: Capacitors in AC Circuits

Lesson 5: Inductors in AC Circuits

Lesson 6: Transformers

Module 4 is all about alternating current (AC) circuits.

It begins with a lesson on what alternating current is, followed by where it comes from (AC sources). Next we encounter the topic of impedance, a subject that is occasionally misunderstood and frequently taught in a more confusing manner than necessary.

We then cover both capacitors and inductors in AC circuits, deriving their contributions to impedance in a straightforward manner while using an in-depth description to enhance the intuitive understanding of these common components.

Finally, we dive into the subject of transformers, powerful devices that are the reason AC power is so much more popular than DC power.

With Module 5, we start looking at components that differentiate electronics from classical electrical engineering- components that are based on semiconductor technologies.

The module begins with a thorough description of semiconductors. In Lesson 2, we explore a topic critical to semiconductors- doping. Without doping, semiconductors would not be at the heart of electronics today.

We then look at our first semiconductor device- the PN Junction, which in many ways is the basic building block of semiconductor technology in general. We then look at diodes; standard, light emitting (LED), and Zener. Each of these are unique and important.

In lessons 7 we explore transistors in depth; what they are, how they work, and why they have been so important to computers since the 1950s. Lesson 8 covers BJT transistors and in lesson 9 we dive into the most popular transistors of all time – MOSFETs. Amp

Module 5 – Semiconductors

Lesson 0: Module 5 Introduction

Lesson 1: Introduction to Semiconductors

Lesson 2: Semiconductor Doping

Lesson 3: P-N Junctions

Lesson 4: Diodes

Lesson 5: Light Emitting Diodes

Lesson 6: Zener Diodes

Lesson 7: Transistors

Lesson 8: Bipolar Junction Transistors

Lesson 9: MOSFET Transistors

Module 6 – Analog Circuits

Lesson 0: Module 5 Introduction

Lesson 1: Half-Wave Rectifier

Lesson 2: Full-Wave Rectifier

Lesson 3: Bridge Rectifier

Module 6 covers analog circuits, including rectifiers, filters, and amplifiers.