Eli5: How do LEDs create light from electricity and why are they so much more efficient than incandescent bulbs?
In: Technology
First why Incandescent bulbs are so inefficient. They operate on the same principle that a glowing piece of wood does in a fire. When things get hot enough, they glow. Same with a bulb filament. In an incandescent light, the Filament can get to around 4500 degrees fahrenheit or 2500 degrees celsius (depending on the color of the light). As you can imagine, most of the electrical energy goes to making heat, not light, so incandescent bulbs are only around 7% efficient. In other words, when you use an incandescent bulb, you are making 93% heat and 7% light.
Instead of relying on thermal radiation, like Incandescent bulbs, LEDs rely on electroluminescence. Electroluminescence is basically when you take a material starved of electrons (the smallest pieces of electrical charge), and feed it electrons, and photons (pieces of light) get released in the process. These days we can make semiconductor materials with regions of excess electrons, and electron “holes”, and make LEDs out of them.
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