How do LEDs work

Have you ever wondered why, when a bunch of electrons fly out of their orbit —thus  occupying a higher energy level inside the atom—, once they are back to their initial place due to the nucleus attraction, they are able to release the extra energy —the one they got when briefly occupying a higher orbit— through a photon discharge?

Probably not. At least, we don’t usually do it. Even though the above is just the basic explanation of the phenomenon that allows an incandescent bulb to emit light. But, certainly, this is nothing to keep us awake at night.

However, it is fairly usual that we wonder, when we come across a LED, about the strange process that we see: a process that allows a solid to be able to transform electric power into light. And0 it is also usual that, when we have the intention to present an informational document that includes the word LED, we feels compelled to offer a preliminary explanation about the physical phenomenon behind this mechanism.

All this usually brings the person who plays the role of —or finds him/herself in the role of— the expert, to end up including an initial paragraph full of concepts like semiconductor, conduction bands, and so on. And, inexorably, his/her explanation will be too brief as to fully clarify the phenomenon, and too long, causing most readers to yawn by the end of it.

Once this procedure is complete, most of us will simply assume that we are seeing something that emits light in exchange of electric power. Something that surprised us when it first came up, some years ago, to join the rest of light sources already existing, senior by then. Some light sources whose working mechanisms we were already used to ignore.

That’s how LED work. In the upcoming posts, we will talk about their features.

ca2L Team.

P.S.- https://www.nema.org/Products/Documents/ies-led-doc-tm16.pdf