LYCOS RETRIEVER 
Light-Emitting Diode: Electric Current
built 608 days ago
An LED, or light-emitting diode, is a special type of diode that emits light when connected in a circuit. A diode is an electronic device that has two electrodes arranged in such a manner as to allow electrical current to flow in one direction only. With its ability to control the flow of electrons, a diode is often used as a rectifier, which is a device that converts alternating current into direct current. Alternating current is an electric current that flows first in one direction and then in the other. Since alternating current fed into a diode can move in one direction only, the diode converts the current to a one-way flow known as a direct current.
Source:
A LED is a special type of semiconductor diode. Like a normal diode, it consists of a chip of semiconducting material impregnated, or doped, with impurities to create a structure called a pn junction. Charge-carriers (electrons and holess) are created by an electric current passing through the junction, and release energy in the form of photons as they recombine. The wavelength of the light, and therefore its colour, depends on the bandgap energy of the materials forming the pn junction. A normal diode, typically made of silicon or germanium, emits invisible far-infrared light, but the materials used for a LED have bandgap energies corresponding to near-infrared, visible or near-ultraviolet light.
Source:
An LED is a special type of semiconductor diode. Like a normal diode, it consists of a chip of semiconducting material impregnated, or doped, with impurities to create a structure called a pn junction. Charge-carriers (electrons and holes) are created by an electric current passing through the junction. When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon as it does so.
Source:
MORE ABOUT
Electric Current