Old fashioned incandescent light bulbs pass electricity through highly-resistant wire filaments, that get hot and glow brightly. This process occurs inside a glass containment under vacuum, or holding an inert gas to extend filament life. But this method is energy-greedy when we compare it to LEDs. This post explains how these light emitting diodes work.
How Light Emitting Diodes Brighten Our Lives
An LED is a semi-conductor light source, with resistance between a conductor like copper, and an insulator such as glass. When electric current flows through it, it emits light, although not in the same way as an incandescent light bulb. Here’s how light emitting diodes work differently:
- Electrons in an LED recombine with electron holes in a different position, without them.
- This releases energy packets in the form of photons that emit the familiar light we see.
- However, the actual color of that light depends on the energy necessary to achieve this.
But white LED light is a result of combining basic red, blue, and green colors through using multiple semiconductors. Although technicians can also achieve this by adding a layer of light-emitting phosphor on the semiconductor device.
A Very Short History of These Diodes Emitting Light
LED’s first appeared commercially in 1962, although they only emitted low-intensity infrared light. They often functioned as indicator lamps, instead of small incandescent light bulbs. However, the idea caught on when designers realized the potential energy savings.
Nowadays we see them almost everywhere we go, including aviation lighting, fairy lights, automotive headlamps, and advertising and general lighting. But we also find them in traffic signals, camera flashes, lighted wallpaper, horticultural grow lights, and medical devices too.
They have many advantages over incandescent light bulbs. These include lower power consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. But they do need electronic support components to function, whereas incandescent light bulbs are stand-alone devices.
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