To start, I recommend reading some of SparkFun’s tutorials on the basics and avoid using micro-controllers (micro:bit, Arduino, and RaspberryPi) until you need them. You can also look up most of this stuff in a general search on Google (and Wikipedia), but SparkFun is probably the most helpful starting point.
To get started, we need to clarify some terms: what are electricity, voltage, power, current, and resistance and how do we measure and calculate them?
Electricity is a natural phenomenon that occurs throughout nature and takes many different forms. In this tutorial we’ll focus on current electricity: the stuff that powers our electronic gadgets. Our goal is to understand how electricity flows from a power source through wires, lighting up LEDs, spinning motors, and powering our communication devices.
Electricity is briefly defined as the flow of electric charge, but there’s so much behind that simple statement. Where do the charges come from? How do we move them? Where do they move to? How does an electric charge cause mechanical motion or make things light up? So many questions! To begin to explain what electricity is we need to zoom way in, beyond the matter and molecules, to the atoms that make up everything we interact with in life.
This tutorial builds on some basic understanding of physics, force, energy, atoms, and fields in particular. We’ll gloss over the basics of each of those physics concepts, but it may help to consult other sources as well.
Voltage, Current, and Resistance:
Electricity is the movement of electrons. Electrons create charge, which we can harness to do work. Your lightbulb, your stereo, your phone, etc., are all harnessing the movement of the electrons in order to do work. They all operate using the same basic power source: the movement of electrons.
The three basic principles for this tutorial can be explained using electrons, or more specifically, the charge they create:
Voltage is the difference in charge between two points.
Current is the rate at which charge is flowing.
Resistance is a material’s tendency to resist the flow of charge (current).
So, when we talk about these values, we’re really describing the movement of charge, and thus, the behavior of electrons. A circuit is a closed loop that allows charge to move from one place to another. Components in the circuit allow us to control this charge and use it to do work.
Georg Ohm was a Bavarian scientist who studied electricity. Ohm starts by describing a unit of resistance that is defined by current and voltage.
In general physics terms, power is defined as the rate at which energy is transferred (or transformed).
So, first, what is energy and how is it transferred? It’s hard to state simply, but energy is basically the ability of something to move something else. There are many forms of energy: mechanical, electrical, chemical, electromagnetic, thermal, and many others.
Energy can never be created or destroyed, only transferred to another form. A lot of what we’re doing in electronics is converting different forms of energy to and from electric energy . Lighting LEDs turns electric energy into electromagnetic energy. Spinning motors turns electric energy into mechanical energy. Buzzing buzzers makes sound energy. Powering a circuit off a 9V alkaline battery turn chemical energy into electrical energy.
You will also need to be able to Read a Multimeter and Interpret Schematics.
The final part to this post is two-fold:
First, the two types of Current;
Second, the basic components: Switches, Resistors, Transistors, Capacitors, LEDs, Diodes, and Integrated Circuits.
You will also need to get your hands on a Breadboard, Wires, and a Power Supply of some description (Batteries can work pretty well, but I recommend a good, cheap Breadboard Supply that works well to get started.)