LEDs are everywhere. Chances are you’re reading this article about LEDs because of the light emitted by one or more LEDs. But what exactly is an LED? In this guide, we’ll teach you the basics.

LED stands for Light-Emitting Diode, an electronic device made of two types of semiconductor material. Similar in concept to the semiconductor material used in computer components (such as RAM, processors, and transistors), diodes are devices that allow the flow of electricity to occur in only one direction.

An LED does the same thing. It blocks the flow of electricity in one direction, while allowing it to move freely in the other. When electricity, in the form of electrons, travels across the junction between the two types of semiconductor material, energy is released in the form of light.

The credit for the first use of an LED goes to Oleg Losev, a Russian inventor who demonstrated an LED in 1927. However, it took almost forty years for the invention to be put into practice.