Light Emitting Diode (LED)
LEDs, or light-emitting diodes, are widely used as a standard light source in electrical devices. It may be used in a variety of ways, from your phone to large advertising billboards. They find applications in devices that display the time and various forms of data.Table of Contents
What is Light Emitting Diode
When an electric current passes through it, a light-emitting diode emits light. It is a semiconductor-based light source. When current is passed through the LED, electrons recombine with holes, resulting in the emission of light. It's a sort of diode that shares many of the same features as a p-n junction diode.
This means that an LED permits electricity to flow in one direction but prevents it from flowing in the opposite direction. A weak layer of heavily doped semiconductor material is used to construct light-emitting diodes. When forward biassed, an LED emits colored light at a specific spectral wavelength depending on the semiconductor material used and the amount of doping.
LED Symbol
The LED symbol is demonstrated in the image below. The p-n junction diode's symbol is similar to this one. The two arrows indicate that the diode is emitting light, which is also the main difference between these two symbols.
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Working Principle of LED
The free electrons are in the conduction band, whereas the holes lie in the valence band. The electron from the n-type semiconductor material would pass the p-n junction and unite with the holes in the p-type semiconductor material if the p-n junction had a forward bias. As a result, the free electrons would be in the higher energy bands.
The figure demonstrates the elementary process principle
As the voltage drops from the conduction band to the valance band during this movement of free electrons and holes, the energy level changes. The motion of the electron causes a release of energy. The release of energy in the form of heat in standard diodes. However, with an LED, the release of energy in the form of photons would result in the emission of light energy. That this whole process is called electroluminescence, and the diodes are called light-emitting diodes.
The forbidden energy gap determines how much energy is discharged in the form of light in LEDs. The wavelength of the light produced could be adjusted. As a result, the light color and visibility cannot be controlled based on its wavelength. By dopping it with various impurities, the color and wavelength of the light emitted may be determined.
Uses of LED
LEDs are used in a variety of fields, such as optical communication, alarm, and security systems, remote-controlled operations, robotics, and so on. Because of its long-lasting capability, low power needs, quick response time, and fast switching capabilities, it is used in a variety of applications. The following are some of the standards that LED adheres to:
- Used for TV back-lighting
- Uses in displays
- Used in automotive
- LEDs used in the dimming of lights
Types of LED
LEDs are used in a variety of industries, such as optical communication, alarm and security systems, remote-controlled operations, robotics, and so on. Because of its long-lasting capability, low power needs, quick response time, and fast switching capabilities, it is used in a variety of applications. The following are some of the standards that LED adheres to:
The following is a list of the various varieties of LEDs that have been designed for us. Lighting LED
- Miniature LEDs
- Bi and Tri-Colour
- Flash LED
- Red Green Blue LEDs
- High-Power LEDs
- Alphanumeric LE
Main LED materials
The main semiconductor materials used to manufacture LEDs are:
- Indium gallium nitride (InGaN): blue, green, and ultraviolet high-brightness LEDs
- Aluminum gallium indium phosphide (AlGaInP): yellow, orange, and red high-brightness LED
- Aluminum gallium arsenide (AlGaAs): red and infrared LEDs
- Gallium phosphide (GaP): yellow and green LEDs
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