Light-emitting diode - Wikipedia

Light-emitting diode - Wiki - Department of Chemical Engineering

LED Lights - How it Works - History

LED lamp - Wikipedia

Light-emitting diode - Wikipedia

Why It Was Almost Impossible to Make the Blue LED

OLED - Wikipedia

What is LED? - Definition, Working, Properties, Uses, Advantages

Light-emitting diode - Wikipedia

File:Arduino led-4.jpg - Wikipedia

File:Orange LED emitting.png - Wikipedia