How does a LED light bulb work

A brief look at how LED light bulbs work.

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How does an LED light bulb work - LED Green Clock
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Today our blog post looks at how does a LED light bulb work. Simple put an LED light bulb works by containing several LEDs. Under power a current passes through the LED which then give out light.

So what is an LED?

What is a LED and how does it work?

Firstly LED stands for Light Emitting Diode. LEDs have been around for a long time. Remember those old displays with the green numbers? LEDs emitted green light produced them.

So how do LEDs work?

LEDs are small pieces of semiconductor that give off light when a current passes through them. And semiconductors are materials that are poor conductors. For example, silicon or gallium-arsnide. Then, a more conductive material is added to them in a process called doping. By doping these materials we can control how and when electrical currents flow through them. Semiconductor technology is the basis for the electronics in our phone and computers.

LEDs are a very simple semiconductor device. Normally the base material is aluminum-gallium-arsenide. Which is then doped making it more conductive. In a single LED itself there is a flat round piece of this material with two connectors. And on top of the LED there is normally a lens focusing the light produced.

Historically LED light bulbs contain 3 different LEDs. One red, one blue and one green. The three colors combine to form white night. However recent research has developed a white LED. In fact the LED is blue. A phosphorous coated changes the blue white to white. Thus LED light bulbs made with these LEDs only require one LED in place of the normal three.  

How does a LED vintage filament bulbs work?

So, in an normal LED light bulbs there are lots of little square LEDs happily emitting light. Hidden away behind a frosted coating. Then one day a team at the University of California Santa Barbara developed a new process. Instead of the LEDs being little squares they where spread along a thin wire. Then a transparent covering sits on top with a phosphor coating. This coating changes the blue light from the LED to a warm yellow light. And the metal strip looks like the old vintage filaments.

Additionally the LEDs wrap around the wire. This produces light in all directions. Again, like the old incandescent filaments.

How does a LED light bulb work?

Now that we have an idea of how LEDs work we are on our way to understanding how LED light bulbs work.

Within a LED light bulb there are several components:

  • LED Chips. These are the pieces of semiconductor that produce the light.
  • A lens to focus the light.
  • A heat sink to take heat away from the LED.
  • Circuit driver to turn on and control the LED chips
  • The housing, which is the bulb itself
  • The base, with its screw connector

As discussed in the earlier section the LED chip, the bit that produces the light, can be structured in different ways. For example as a single device, or multiples on a circuit board, or formed into a filament.

Hopefully this has answered the question how does a LED light bulb work.

To summarize and LED light bulb contains multiple LEDs. Or one long thin strip coated with LED material. Then current passes through the LEDs and they emit light. Finally the lens focuses the light and you have a LED light bulb.

If you would like to know the best LED light bulbs to buy then why not look read our article on the best E26 bulbs.

Also if you want to find out how an actual LED manufacturer make their bulbs then see this excellent blog post from TCPI.