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!
Resistors
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:
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: http://resistor.cherryjourney.pt/
If you’re interested in the science behind how resistors work then you should read up on ohms law.
Capacitors
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 decoupling or 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:
LEDs (Light Emitting Diodes)
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.
Transistors
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 For Beginners 