An LED, or Light Emitting Diode, is a semiconductor device that emits light when electrical energy is applied to it. It consists of a computer chip that is attached to a positive power lead and a negative power lead. The ‘anvil’ on the top of the negative lead holds one side of the chip and the ‘whisker’ on top of the positive lead holds the other side. The LED is encased in clear epoxy resin.

The semiconductor chip contains two sides: the P-side has missing electrons called ‘holes’ that cover the area and the N-side is covered with electrons. Where the two sides meet, a PN junction is formed. When a current is applied to the electrodes, electrons from the N-region flow into the P-region where energy is then released in the form of photons of light. The color of the light depends on the type of materials used to construct the LED chip.