How LEDs work

What Is An LED and How Do They Work?

The majority of people know about incandescent bulbs and that warm glow they provide that cuts through the darkness and brings light into our life. We all know how they make us feel and that they do work. However,  most people (including those of you who are reading this now) probably have no idea how they actually work.

There’s nothing wrong with that, there is so much to be aware of and understand in the world that we mostly spend our time taking in knowledge of the things that matter to us most and for a huge percentage of people, its only important knowing that incandescent light bulbs do work, not how they work.


While we are on the subject though – incandescent bulbs are able to produce light because the filament inside is heated until it glows. About 90% of the energy used to turn an incandescent light on is actually used to generate that heat.

Before you can understand more about LEDs, it’s vital to understand what they are a replacement for and why.

Many governments around the world have in recent years been trying to phase out the use of these traditional types of light bulbs, mainly due to their high energy consumption. The idea is that they will be replaced with more energy-efficient lighting solutions such as LEDs.

However, and this brings us back full circle as to why we explained how LEDs work, as LEDs are unfamiliar territory for many people, you may wonder why there is a need to change and making the change from what you know works (even if you didn’t know ‘how’ it worked) to something completely new can be overwhelming.

In the following post though, we want to put your mind at ease a little about making that change by helping you to understand what LEDs are and how they work. We are sure this will help you see why you should change out your incandescent bulbs for modern LED lights.

What is an LED?

So first things first, we have all seen those three letters on numerous products, but what does LED actually mean? It’s an abbreviation that stands for ‘Light Emitting Diode‘. The first two-thirds of the name are fairly self-explanatory – we hope – with light emitting meaning it produces light/gives off light. However, you might need further explanation about what a diode is and what it does. In order to explain this, as Jennifer Aniston once said in a hair product commercial ‘here’s the science bit’.

All diodes, in general, emit electromagnetic energy particles (photons). However, it’s only specific kinds of diodes that emit that energy in the form of light rather than heat. An LED is an SSL or solid-state lighting technology. This means that the light it produces is from a solid piece of matter. In an LED the solid piece of matter is a 2-lead semiconductor. More on that later.

If you still need any help understanding how LEDs work, check out this great video from Luxeon:

Basic Types of LEDs Used

As noted earlier, the vast majority of us have seen and used LEDs in all manner of ways. There are two basic kinds used and these are as follows:

  • Indicators – low powered, inexpensive devices used in panels, cars and all kinds of electronic devices as indicator (and warning) lights.
  • Illuminators – higher powered LEDs that produce illumination. You probably have this kind of LED at home or even in your office. They come in an amazing range of different colors shapes and sizes. You are able, therefore, to find an LED to suit most applications.

How Do They Work?

Now to the nitty-gritty. The reason an LED can produce light is that of two semiconductor materials and how they are arranged between its electrodes.

The semiconductors in question are:

  • P-type – Semiconductor that has extra holes or as they are more commonly known, extra particles with a positive charge
  • N-type – Semiconductor with extra electrons, or extra particles with a negative charge

When the P-type semiconductor is connected to the positive electrode and the N-type semiconductor is connected to the negative electrode, the electrons are activated and start to flow from the negative side of the junction to the positive. As these negatively charged electrons move across cross the positively charged particles, the create light.

Normally the conductive material used in LEDs is AIGaAs or Aluminum-Gallium-Arsenide. However, it is worth noting that there are alternative kinds used. These materials are chosen because of their ability to produce photons that when they are released with appear on the visible part of the spectrum of light. The amount used and type of material chosen determines the light color because all conductive materials produce photons with different wavelengths, which in turn as an affect on how they appear and are perceived by our eyes.

Geeky Light Fact – White LEDs don’t exist, well not anything that is completely and purely white. Any so-called white LED lights either have an orange or yellow coating (usually phosphor) that turns the color of the LED into white light, or they consist of a mixture of various colored LEDs.

So there you have it, we hope that has cleared up some of the mystery surrounding LEDs for you. We also hope you can now see that as LEDs are significantly more energy-efficient than incandescent bulbs, converting and replacing to these modern lighting solutions is a very sensible thing to do. Not only do they cost less in the long run, because they need replacing less; but, they are also more versatile when it comes to offering options for different colors of lights.

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