The Light-Emitting Diode (LED)

You can purchase LEDs in a variety of designs. Open a catalog of an electronics supplier and you find a long list of LEDs in different colors, shapes and intensities.

In the experiments, you use standard 5mm LEDs of different colors.

The colors are determined by the materials used in the LEDs. These determine the main characteristics.

Standard 5mm LEDs of different colors. (Enlarge)

Circuit symbol LED. LEDs have two terminals which are designated as anode (A) and cathode (C). In the picture LEDs of different colors are shown.