Leds (Light Emitting Diode), also called light-emitting diodes (leds), it is a solid-state semiconductor devices, can be directly put electric into light.
The heart of the LED is a semiconductor chip, the chip attached on a bracket, at the end of the end is negative, the other end connected to the power of the anode, the whole chip is encapsulated by epoxy resin.
Semiconductor chip consists of three parts, one part is a p-type semiconductor, dominated by holes in it, the other end is n-type semiconductor, mainly electronics, here in the middle is usually one to five cycles of quantum well.
When a current flows through a wire to the chip, electrons and holes will be into the quantum well, in a quantum well electron and hole compound, then to home light.