The abbreviation LED stands for Light Emitting Diode. This is a semiconductor that emits light as soon as current flows in the forward direction. Depending on the material used, an LED shines in different colours.
While in the early days of this technology only red and green LEDs were possible, the entire colour spectrum from infrared to ultraviolet light can now be covered. With the last major development step so far, white LEDs have also become possible.
A distinction is made between two different types of LEDs, whereby the more modern SMD LEDs are clearly superior to conventional wired LEDs due to their higher potential output and have largely replaced them.