Light-emitting diodes are referred to as LEDs. Made of compounds containing gallium (GA), arsenic (AS), phosphorus (p), nitrogen (n), etc.
When electrons and cavities are combined, they radiate visible light and can be used to make light-emitting diodes. In the circuit and instrument as the indicator light, or composed of text or digital display. Gallium arsenide diode glows red, gallium phosphide diodes green, silicon carbide diode yellow light, gallium nitride diode blue light. The chemical properties are also divided into organic light-emitting diode OLED and inorganic light-emitting diode LEDs.