Basic Electronic Components – Part 1

The world of electronics comprises of some common key components which you’ll see in just about every single electronics circuit and PCB in any electrical appliance.

Understanding these common components and what they do is key to mastering electronics and is very important as you begin to design and build your own electrical circuits and appliances.

Let’s get started!


electronics components - resistor
A basic resistor

The easy way to remember what a resistor does it to take the clue from the name – it resists! In electronics, a resistor resists electrical current. Let’s take a very basic circuit so we can understand the importance of using resistors:

basic circuit
A basic circuit with an LED, battery and resistor

Consider the power source in the bottom left of the drawing. For the sake of simplicity let’s assume that this is a 9v battery. Were we to connect our 9v battery directly to our tiny bulb or LED, we would either blow the bulb, or we would cause the lifespan of the bulb to be very short indeed!

This is where resistors come into play. Once the current hits the resistor, it is reduced before carrying on around the circuit. Essentially a resistor just comprises of a copper coil, depending how many times it is coiled and also the thickness of the coil will determine by how much the current is resisted.

As you start looking at electronics and at circuits you will often see different colour resistors, there is a standard behind this and there’s a very cool website which will allow you to enter the colours found on a resistor to determine the level of resistance that it will offer:

If you’re interested in the science behind how resistors work then you should read up on ohms law.


basic capacitor
A basic capacitor

A capacitor is essentially a temporary power storage. It is used to hold an electrical current for a certain amount of time before it is discharged to be used on other components within a circuit.

There are a number of reasons why we would use a capacitor in a circuit, but most commonly it is because of one of the following:

  • All electrical circuits generate ‘noise’ which is essentially unwanted ripples in electrical currents. In larger circuits, these ripples can cause us problems as they can be very damaging to components that are delicate and cannot handle large surges of power. In this instance, a capacitor would be capable of absorbing this ripple of current and storing it. These are often referred to as decouplingĀ orĀ bypass capacitors.
  • Capacitors can act as temporary power supplies for other components. For example if there is a slight drop in power from an actual power source within the circuit, the capacitor can step in and provide the additional required power for the components that need it
  • Circuits that require a time-delay system such as a blinking or flashing light circuit can utilize capacitors in conjunction with a resistor to vary the voltage in a circuit switching an LED or bulb on and off repeatedly.

You will find capacitors in just about every circuit and electrical appliance you can think of! They come in all different shapes and sizes depending on the circuits they are used in and they all offer different storage capacities, here are just a few:

lots of capacitors
A wide range of capacitors

LEDs (Light Emitting Diodes)

three basic leds
Three basic LEDs

LEDs are used for so many different reasons in electrical circuits. They are essentially very small and basic light bulbs. In the most common of instances they may be used to show that a circuit or an appliance has power. On your laptop or computer they are used to show your WiFi adapter is powered on, or to show that there is activity on your hard disk.

Generally speaking, LEDs come in two different types; single colour and multi colour. They also usually come in different power formats; low power and high power.

Imagine a simple laptop power LED, this would be a simple low power single colour LED. On the other hand, a multi colour LED might be used to alert to the status of something (think red for low power, amber for medium power and green for full power, or perhaps to signify battery capacity)

In terms of their power, a low power LED will simply be used to signify something and will use very little in terms of voltage. High power LEDs on the other hand will be more commonly used to illuminate something, these will obviously draw my voltage and in addition, further considerations are required for things like heat dissipation.


A basic Transistor
A basic Transistor

A transistor is where something of significance begins to happen within our electrical circuit. In its most basic form (and to keep our explanation reasonably simple!) you must imagine a transistor as an electronic switch, one that can turn a current on and off. Alternatively, you could consider a transistor to be similar to a simple relay.

Consider a basic circuit that has a power source (battery), a resistor and an LED. Were we to introduce a transistor into this example, we would have the transistor turn on and direct current through it once it received power from the power source (battery)

Many different types of transistors exist though. For example, PNP (Positive Negative Positive) transistors are used when a small current needs to be ‘redirected’ into a much larger current for various applications. You may find a PNP transistor in something like a security light, one that is required to come on in the dark or when there is an absence of sunlight.

That’s it for now! Part 2 will look at things like inductors and more complicated integrated circuits.

In the meantime, remember that if you’re new to the world of electronics and are looking for the perfect kit for beginners, then check out my post here which has some great advice on getting yourself a fully comprehensive electronic kit.




Electronics kits for beginners

If you’re new to the world of electronics you will probably appreciate the sheer volume of information on the Internet about the subject. In many ways this is great but also for most people it can be extremely overwhelming.

When i began my electronics journey I was lucky enough to have some great introductory books that took me through the fundamentals in a clear and easy to understand manner. With the evolution of the Internet we now have every conceivable bit of information at our fingertips, but finding the right resources can be hard work and frustrating!

If you’re beginning your electronics journey then I highly recommend you invest in a couple of good books and electronics kits that can make the beginning of your journey fun, exciting and most of all not overwhelming!

Greg Carpenter the world renown electronics master offers a fantastic set of resources for beginners electronics enthusiasts as well as a whole book dedicated on making basic circuits and an explanation as to all the components and tools you need and where you can get them from.

Gregs resource comes with all of this:

Introduction to basic electronics This is the bible of introductory electronics and explains in detail the fundamental concepts. It’s a very easy to understand but in depth book

Building simple circuits A great book that explains how to build simple circuits. It gives you all the materials and tools you’ll need and detailed instructions on building them

Basic electronic projects Once you’re comfortable with building a very basic circuit, this book has some fantastic little projects on building some very cool electronic gadgets!

Circuit symbols referenceOnce you begin to start designing your own electronic circuits you will need to be adept with understanding what all the different symbols mean. This book shows all the common symbols and what they mean

Radio and RF theoryIn the wireless world we live in today its important to understand the concept of wireless and RF technology. This book does a great job of explaining RF in detail and how it applies to the world of electronics

Glossary of electronic terms The world of electronics contains a very large vocabulary and terminology. It can be quite overwhelming at times and there is a lot to remember. This book contains all the electronic terms and an explanation as to what they are. A great little reference book

Soldering part 1Soldering is an absolutely essential skill to learn if you want to really advance your electronics building skills. Although it can be a daunting skill to practice, this book gives you some guidance on how to become a proficient solderer

Soldering part 2Because soldering is such a diverse skill, one book wouldn’t cover everything. Part 2 of the above expands on the current soldering knowledge and skills you’ll now have

Secrets of ohms lawOhms law is one of the most important fundamental concepts you’ll ever need to understand as an electronics enthusiast. This book is a fantastic theoretical look at ohms law and provides some very compelling reading into it

As far as beginners electronics kits go, I couldn’t recommend one higher than the resource pack Greg has put together. It’s an invaluable asset for anyone beginning their exciting journey into the world of electronics.

Check out Gregs beginner electronics kit right here

Welcome to electronics for beginners

I’ve been an avid electronics enthusiast for a couple of decades now and started this website as a way to share my knowledge and experience with the world. I quickly realised the internet has a lot of resources for beginner electronics but perhaps not that are quite as comprehensive as what I have in mind.

The world of electronics is a truly fascinating one and one which has evolved dramatically over the past couple of decades. Circuit boards are getting smaller and so are the microchips that we use. But the fundamentals are pretty much the same and this is what is at the heart of electronics.

Mastering these fundamentals is what I wanted this website to be all about. I want to start at the beginning with the most basic of terminology and explaining how basic boards and circuits operate. From here we can expand and start looking at more complex systems perhaps those you might find inside your computer.

As a beginner you will start by understanding how one of these operates:

Basic circuit board

And eventually you’ll be able to understand how one of these works:

Complex Circuit Board

Stay tuned and please subscribe to my updates!