Light-Emitting Diodes

Diodes - conduct electricity in one direction. They use DC current and low amperage.

Periodic Table of the Elements

Semiconductors:
  • photocells
  • light emitting diodes
  • laser diodes
  • LEDs are composed of tiny crystals of gallium, Ga from column IIIA, and atoms of elements from Group VA elements.

    Size of an individual LED. I am holding a typical size of LED between my thumb and little finger.

    These are greatly enlarged images of LEDs, left one without the plastic lens, straight down.

    Railroad crossing flasher using a large number of LEDs. They last 10 times longer and use 1/10 the energy of an incandescent light bulb in the same situation.

    Which color of LED goes out first? The blue, green, yellow, orange, or red?
    The LED which does not show to your eye is an infra-red LED.
    Which color LED goes out first? It requires the highest voltage, most energy. Click on the picture below to get the video. You may have to then follow the instructions posted.
    The video was created by students from Mrs Analice Sowell's Chemistry II: Material Science class at Memphis University School.

    This page was designed and is maintained by Mike Condren. If you have materials
    that you would like to contribute, contact me at mcondren@cbu.edu