Posts: 1
Joined: Wed Dec 19, 2007 8:56 pm


Postby yolandy » Wed Dec 19, 2007 9:12 pm

Hello. This is Yolandy. This is my first time using this website. Thank you for having it open for me.

Will you please explain how LED lights work?

Thank you.

Former Expert
Posts: 932
Joined: Wed Oct 03, 2007 12:24 am

Postby barretttomlinson » Thu Dec 20, 2007 1:25 am

Try searching Google for "how LEDs work". It will return several good explanations, one of which is:


Hope this helps.

Wen Phan
Former Expert
Posts: 1
Joined: Wed Nov 07, 2007 3:32 am


Postby Wen Phan » Fri Feb 08, 2008 1:45 am

LED stands for "light-emitting diode." A diode consists of two "special" materials that are "put" together. For a regular (non-light emitting diode), when a voltage is applied with one polarity, current flows. In the other polarity, current does not flow. For an LED, when you apply the right voltage polarity (also called a bias) such that current flows, some of the electrons that flow in the current "move" to a lower "energy state." When an electron moves to a lower energy state in an LED, it emits a photon, or light. The amount of energy level change (also called the bandgap energy) determines the color (frequency) of the light.

I hope this helps.


Return to “Grades 9-12: Physical Science”