LED book cover

How To Use Light Emitting Diodes

Ron Heath

Version 1.0
Copywrite 2012
All Rights Reserved


  This book is intended to be both too simple and too complex. The reader who is in a hurry may skip over the parts that are too far one way or the other, however, I have found useful nuggets of knowledge while reading the most simple things, as well as things that seemed to be too complex to be actually useful.

     Commercially available light emitting diodes started out as fairly dim lights that had a size of around 0.2 inch diameter and a length of around 0.34 inches. These were used as indicator lights for electronic devices. In fact, this is the most common place that you will see them today.
     The first color was red, but green and yellow soon followed. Infra-red LEDs soon became available also. The infra-red LEDs are used in the remote control for TVs, and for the small flag sensors that are in most anything that moves.
    All different shapes of LEDs have become available. Some of these have been installed onto printed circuit boards with plastic light pipes that direct the light to the front panel.
   Ultra-violet, or black light LEDs are now available. These are used in black light flashlights. Black light flashlights are used in law enforcement for viewing powders that glow in black light.
   Blue LEDs are rather recent, but they are also commonly available now.

Chapter 1