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What Is The Reason For The LED Light Emitting Diode?

Jan. 23, 2019

The LED Light Emitting Diode is a type of semiconductor diode that converts electrical energy into light energy. LED LEDs, like ordinary diodes, consist of a PN junction and also have unidirectional conductivity. When a forward voltage is applied to the LED light-emitting diode, holes injected from the P region into the N region and electrons injected into the P region from the N region are separated from the electrons and the P region of the N region within a few micrometers of the PN junction. The holes recombine and the fluorescence of spontaneous emission occurs.

The energy states of electrons and holes in different semiconductor materials are different. When the energy released by the recombination of electrons and holes is different, the more energy is released, the shorter the wavelength of the declared light. Commonly used are diodes that emit red, green or yellow light. The reverse breakdown voltage of the LED light emitting diode is greater than 5 volts. Its forward volt-ampere characteristic curve is very steep, and it is necessary to use a series current limiting resistor to control the current through the diode. The current limiting resistor R can be calculated by the following formula: R=(E-UF)/IF

In the LED light-emitting diode type, E is the power supply voltage, UF is the forward voltage drop of the LED, and IF is the normal operating current of the LED. The central portion of the LED light-emitting diode is a wafer composed of a P-type semiconductor and an N-type semiconductor, and a transition layer between the P-type semiconductor and the N-type semiconductor is referred to as a PN junction.

In some PN junctions of semiconductor materials, the injection of a small number of carriers recombines with the majority of carriers to release the remaining energy in the form of light, thereby directly converting the electrical energy into light energy. The PN junction adds a reverse voltage, and a small amount of carriers are difficult to inject, so they do not emit light. Such a diode fabricated by the principle of injection electroluminescence is called an LED light-emitting diode, and is generally called an LED. When it is in a forward working condition (ie, a forward voltage is applied to both ends), when the current flows from the anode of the LED to the cathode, the semiconductor crystal declares light of different colors from ultraviolet to infrared, and the intensity of the light is related to the current.

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