Monday, May 16, 2011

How LED Light Bulbs Work

Simple LED circuit

If you’ve followed the latest trends in environmentally conscious lighting at all, you know that LED light bulbs are going to be replacing your incandescent and CFLs in the next few years. But how exactly does an LED light bulb work?

More and more, the advantages of using LED lighting are becoming clear.

  • Eighty percent more efficient than incandescent
  • Safer. No mercury, unlike CFLs
  • A pleasant, warm light
  • A lifespan of more than 30 years
  • Very little energy is wasted as heat. 

What is it about an LED light bulb that allows it to do all of this?

Oh no. Not history! I’ll keep it brief. LED stands for Light Emitting Diode and it was invented in 1962. At first LEDs could only emit a red light, like the ones you would find in an old digital alarm clock. As time went on, they discovered how to use the diodes to emit nearly the entire light spectrum. Today they are used in everything from TV screens, to small electronics, to light bulbs.

How the LED works
Magic. Ok it’s not magic, but I’m a writer not an engineer, so I’ll do my best to give you the real answer. The LED (light emitting diode) works by using an electric current traveling through a negatively charged anode to a positively charged cathode. What is this science fiction you ask? Basically, a diode only allows an electric current to travel in one direction. This current causes electrons to recombine, which releases energy in the form of photons, AKA light.

Why LEDs last so long
Unlike an incandescent light bulb, there is no filament, so there is almost nothing to burn out. The LED is a simple electronic circuit and has no moving parts, and is a solid state device. It’s essentially a small circuit like you might find in a computer chip. Without any components to burn, or wear out from movement, an LED can last a nearly infinite amount of time.

Why LEDs Are So Energy Efficient.
This question also actually relates to why an LED runs so much cooler than a regular light bulb. To understand we need to see how an incandescent works. An incandescent light uses a strong electrical current to heat a thin metal wire, called a filament. The metal grows so hot that it begins glow. The metal cannot ignite because it is contained inside a vacuum in the bulb, however it does give off a tremendous amount of energy. However, only about 20 percent of this is energy is in the form of light, the rest is almost all wasted as heat.
As mentioned above, LEDs do not use heat to produce light. Instead it uses a small electrical current to excite electrons, which in turn release energy as light. Only a very small fraction of the energy is lost as heat.

Hopefully this helped explain to you how an LED light bulb works. It’s not magic after all. 
To learn more about LED lighting, or to find a wide selection of LED light bulbs to upgrade your home or business with, visit our sister site, Wholesale LED.

Have more questions or want to add something to the conversation? Leave a comment below. 


  1. You have a great blog buddy. Keep writing this informative content.


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  2. This article never does get around to describing how an LED light Bulb works?
    It describes how an LED works but not how and LED based light bulb works. For instance how is 115vac converted to a dc voltage for the LED?
    Also, I would like to find out if the light output (in lumens) of an LED bulb is the same as its incandescent equevelent.
    And, LED bulbs that I have used do heat up. So they are equipped with heat sinks.

    1. Some LEDs do heat up which, I believe, comes from the electronics they're mounted on while others emit no heat. I have some in my house that do have hot heatsinks while others are completely cool to the touch so it's not the LED itself producing the heat.

  3. Nevada Jockey, try this link for your answer if you didn't get one yet

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  6. Great Post!!
    You have posted such a nice post which is knowledgeable and impressive. As we know LED is a new technology which is being used on the place of traditional Light blubs. LED lights consume low power and produce high brightness.

  7. Thanks for the answer :)

  8. LED has revolutionized the lighting industry. Impressive technology.


  9. Thanks, Ian! Several people have passed along a similar idea, but suggest tape on the bottom of the battery to remove it. Both make sense. led for signage companies