# Electronics

Welcome 👋 to the first “step” in your Physical Computing journey!

In this module, you will learn about the fundamentals of electricity—voltage, current, and resistance—and how these elements can be used to build circuits that turn on lights, spin motors, and do other “work.” You’ll also learn about an empirically derived relationship, called Ohm’s Law, that relates voltage, current, and resistance together and methods to analyze circuits using Ohm’s Law. Finally, you’ll learn about three common circuit elements (resistors, LEDs, variable resistors), how they work, and how to use them in circuits.

Throughout, you’ll use simulation tools like CircuitJS and Tinkercad Circuits to design and evaluate circuits and then actually build them using physical components.

By the end of this module, you will be prepared to start Module 2—our Intro to Arduino series—where you will begin making with electronics, microcontrollers, and programming!

If you have limited background in circuits and programming, you may also want to consider our series on Making with the Circuit Playground Express (CPX), which uses a wonderful prototyping platform called CPX along with a drag-and-drop visual programming language called MakeCode (that is similar to Scratch).

## Lesson 1: Voltage, current, and resistance

Introduces three key electricity concepts, current, voltage, and resistance, which form the foundation of electronics and circuits.

## Lesson 2: Circuit Schematics

Introduces a visual language for describing circuits called circuit schematics, which are used in component datasheets, CAD programs (e.g., circuit simulators, PCB layout software), and circuit analyses. Also includes an activity using Fritzing to build your own schematics.

## Lesson 3: Ohm’s Law

Introduces Ohm’s Law, one of the most important empirical laws in electrical circuits that describes how current, voltage, and resistance relate together. Also includes an activity to build and explore resistive circuits in CircuitJS.

## Lesson 4: Series vs. Parallel Resistors

Introduces series and parallel resistor circuits, how to analyze them, and why they’re important. Also includes an activity to build and explore series and parallel resistor configurations in CircuitJS.

## Lesson 5: Resistors

Building on Lessons 1 - 4, let’s dive more deeply into resistors and learn about how resistors work, how they’re made, how they’re characterized in terms of both resistance \(R\) and power \(P\), and how to “read” them.

## Lesson 6: LEDs

In this lesson, we’ll introduce one of the most common electrical components in the world: light-emitting diodes or LEDs. You’ll learn about your first semiconductor device, diodes, and how they’re non-ohmic and only allow current to pass in one direction. Then, we’ll introduce a special kind of diode, called an LED, and show how to use them, how to select an appropriate current-limiting resistor, and why resistors are necessary. You’ll also get to physically build stuff, yay!