Learn Electronics


A complete course on electricity, circuit analysis, semiconductors, and more!

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Continue down for an outline of the course.

A motherboard showing a variety of electronics components.

Welcome to Electronics Reference!

This course is the central ‘hub’ of our website. It’s a comprehensive, totally free course that guides learners to mastery of fundamental electronics.


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 1 – Introduction to Electrical Theory:

Lesson 0: Module 1 Introduction

Lesson 1: What is Electricity?

Lesson 2: History of Electricity

Lesson 3: Electrical Power Generation Basics

Lesson 4: Of Atoms and Electrons

Lesson 5: Electrical Properties of Materials

Lesson 6: Properties of Electric Charge

Lesson 7: Electric Field

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.

We then explore what happens when a power source is connected in a circuit; electrons start to move, generating electric current. We then dive into why the electrons move in the first place, in a lesson on 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 our 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. Their characteristics and usage in series and parallel configurations, as well as specialized circuits like voltage dividers round out the module.

Resistors and Resistor Circuits
Capacitors and Capacitor Circuits

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 applies everything learned so far while developing an understanding of new topics. 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 lesson 7, we explore transistors in depth; what they are, how they work, and why they have been so important to computers since the 1950s.

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

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.

Module 1 – Introduction to Electrical Theory:

Lesson 0: Module 1 Introduction

Lesson 1: What is Electricity?

Lesson 2: History of Electricity

Lesson 3: Electrical Power Generation Basics

Lesson 4: Of Atoms and Electrons

Lesson 5: Electrical Properties of Materials

Lesson 6: Properties of Electric Charge

Lesson 7: Electric Field

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 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

Module 6 – Analog Circuits

Lesson 0: Module 5 Introduction

Lesson 1: Half-Wave Rectifier

Lesson 2: Full-Wave Rectifier

Lesson 3: Bridge Rectifier