How Do LED Light Bulbs Work?

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LED lights have grown more popular in the last few years. In no small part because they are very efficient, environmentally friendly, and very quickly falling in cost. But how does an LED light bulb actually work? Read on.

A Brief History of LED Lighting

The first LED, which stands for Light Emitting Diode capable of emitting visible light was first invented in 1962. These lights were very low powered compared to other types of lights, but not very bright. It was the same little red light that you would find flashing in your remote control.

Early experiments with using LEDs for illumination were largely unsuccessful, partly because of low light outputs. In 1994 the first high brightness LED lights were tested, however they had a bluish-white shade of light that was very unpopular.

It wasn't until 2006 that scientists discovered that coating the LED in a phosphor would change the light spectrum to almost any color, including the warm white (yellowish glow) typically found in lighting.

These lights are called "high powered" chips and have been used in LEDs for years. Surface mount chips (SMC) and "Chip on Board" (COB) are thinner wafer like LED sets that emit light in a more even pattern and are typically much more efficient.

How The LED Chip Works

LED lights use anode and cathode to control the direction of the electrons moving through the device. This allows the electrons to recombine, releasing energy in the form of photons, or light. 

What's in an LED Light Bulb?

  • LED Chip: The LED chips are typically arranged in an array inside of the LED. There may be 4-15 "high powered" diodes, or a single COB wafer measuring an inch or so across, or as many as 75-150 smaller, square SMD chipsets. 
  • Lens or diffuser: Since LED lights only shine outward in a 120 degree beam, lenses can be used to concentrate the light down to as low as 15 degrees. Or a glass dome can be placed over it to disperse the light in nearly 360 degrees. 
  • Driver:  Below the array of chip there is a circuit board that houses the driver. The driver takes the 120 Volt AC used by most American lamps and fixtures and converts it to  the low voltage DC current needed to run the chipsets. 
  • Heatsink: The housing for the entire unit is usually made from aluminum or another heat conducting material that will move the heat produced by the driver away from the components of the LED. This keeps the unit from overheating. On some of the high powered units it may even use fins and ridges of aluminum to increase the surface area and improve heat dispersion. 
  • Base: Finally the cap on the bottom of each light uses a standard E26, E12, etc. so that it will connect to a standard light base. 

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