How does an LED work anyway?

29 April

We love the blinky awesomeness that are LEDs.  But have you ever asked yourself, how do they work anyway?

L.E.D. stands for Light Emitting Diode.  OR a diode that gives off light.  A Diode is a type of electronic component that will only allow electricity to flow in one direction.  What makes LED’s different from other diodes is they are very good at emitting light when electricity is run through them.  But how do they do that?

Inside your LED are Gallium alloy crystals.  I won’t bore you with the specifics, you can read Wikipedia if you want more scientific jargon.  However, based on their structure the Gallium  alloy crystals can either be called P-type or N-type.  N-type has an excess of electrons, P-type is missing electrons. Put these two types next to each other and you have the beginning of an LED.

But to make it emit light you need to add electricity to the LED. When you add electricity to the two sides of the LED, electrons will jump the gap between the P and N types of Gallium alloy.  When they jump the gap (actually called a band gap), they emit light.


LED explanation0


So how do you get different colors of LED light?  By alloying different elements with Gallium.  The different elements determine how much energy it takes for the electron to jump the gap.  The larger the gap, the higher energy photon the LED emitts.  So a smaller gap would be a red photon and a larger gap would be a blue photon.  Neato!  Wikipedia has a great list of all the different types of gallium alloys and their corresponding color.

LED’s are very energy efficient and last longer than traditional lighting sources.  LED’s use 7.5 times LESS power than an incandescent bulb and last 40 times longer! (Source Design recycle Inc) So over the life of the bulb you will save a lot of money.

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