What is LED and how does it work?

Do you know what is LED ? Have you used it? Do you know how it works? If you know the answers to these questions then it is a very good thing and if not, there is no reason to panic at all. Because today we are going to get complete information about this in this article.

What is LED
What is LED

LED or also called light-emitting diode. It is a semiconductor device that emits light when it passes current or electricity. Here, light is produced only when the particles (which are electrons and holes) combine with each other in the same semiconductor material. Since light here is generated from solid semiconductor material itself, it is also called solid-state devices. LED has been a very important invention of this era because today it is being used by a large number of people. So today I thought that why should you all be provided complete information about what LED is, so that you people also know about this new invention. So let’s start without delay and know what LED is and how it works.

What is LED?

This LED’s full form is Light Emitting Diode , it is a very latest invention and it is being used most today. This magic light bulbs is used in a very wide range of applications from your cell phone to large advertising display boards. You can see it anywhere. Today its popularity and applications are increasing day by day because it has some such excellent properties. Especially LEDs are very small and with this they use very less power.

We can put these LEDs in the category of “active” semiconductor. We can also compare this diode with the general general purpose diode, but the biggest difference is that it has the capacity to emit different types of light. If both the terminals (anode and cathode) in this LED are connected with a voltage source in its correct polarity, then it can produce light of different colors, it also depends on the semiconductor substance located in it. Does.

The bright light that is generated when the LED is lit is monochromatic and that is of a single wavelength. The output range of an LED is red (at wavelength approximately 700 nanometer) to blue-violet (about 400 nanometer). Some LEDs emit infrared energy (IR) which is also known as IRED (infrare-emitting diode).

An LED mainly consists of two elements of processed material which are P-type semiconductor and N-type semiconductor. These two elements are placed in direct contact and a region is formed which is also called PN junction. They are similar to other diodes but it has a transparent package that helps visible or IR energy to pass.

History of LED

LED was first introduced to the world in 1907 when elecluminescence was discovered by British scientist HJRound at Marconi Labs. Then in 1961, when Gary Pittman and Robert Biard were doing their experiments in Texas Instruments, they discovered that gallium arsenide emits infrared radiation upon contact with electrical current, which they later called infrared LED. Patent created.

The first visible light LED (red) came after that in 1962. It was developed by Nick Holonyak Jr. By when he was working at General Electric. Hence, Holonyak is also called ” father of the light-emitting diode “. Then in 1972, M. George Craford, who was once a student of Holonyak, first reported yellow LED and he increased the light output of red and red-orange LEDs by a factor of 10, which was then I had a great achievement.

Working Principle of LED

A light-emitting diode is a two-lead semiconductor light source. This is a p – n junction diode that emits light when activated. When a suitable voltage is applied to its leads, the electrons in it are recombine with the electron holes in the device. With which they release energy in the form of photons. This effect is called electroluminescence and here the color of the light (which corresponds to the energy of the photon) is determined by the energy band gap of the semiconductor.

LED in full Working Principle detail

The material that LEDs use is basically aluminum-gallium-arsenide (AlGaAs). These atoms of this material are very strongly bonded in their original state. Due to the absence of free electrons, it is impossible to conduct electricity.

Here an impurity can be added which is also called doping, where extra atoms are introduced, which causes the balance of the material to be disturbed. By adding these impurities that are in the form of additional atoms, they either provide free electrons (N-type) in the system or remove the already existing electrons from these atoms (P-Type) from which atomic orbits “Holes” are created. In both these ways materials become very conductive. Here electrons are enabled in the N-type of material under the influence of electric current in traveling from anode (positive) to cathode (negative) and vice versa in the P-type of material. According to the semiconductor property, current never travels in reverse directions in these respective cases.

According to the above explanation here, it is completely clear that how much light will emit from the source LED depends on the energy level of the emitted photon and which depends how much energy is released when electrons jump. Is within the atomic orbits of the semiconductor material.

As we know that its energy level is raised to move the electron from lower orbital to higher orbital. In the same way if the energy level is reduced to move the electron from higher orbital to lower orbital.

And these phenomena are used correctly in LEDs. In P-type doping electrons of LEDs move from higher orbitals to lower orbitals, releasing their energy which is in the form of photons which is light. Orbitals that are far away from each other are light emit with greater intensity. In this process LEDs produce different colors according to different wavelengths. Therefore, what kind of light will emit from the device depends on which type of semiconductor material is used.

Infrared light is produced by using Gallium Arsenide (GaAs) according to the semiconductor. Red and yellow light is produced by using Gallium-Arsenide-Phosphorus (GaAsP) semiconductor. Red and green light is produced by using Gallium-Phosphorus (GaP) as a semiconductor.

Advantages of LEDs:

1. Very low voltage and current is required to light the LED.
Voltage range – 1 to 2 volts, Current – 5 to 20 milliamperes.

2. Here the total power output is much less than 150 milliwatts.

3. Here the response time is very short – which is only 10 nanoseconds.

4. This device does not require any heating and warm-up time.

5. Their size is very small and it is lightweight.

6. Their construction is very rugged and hence it can tolerate shock and vibrations.

7. The lifespan of LED is more than 20 years.

Disadvantages of LEDs:

1. If a little too much voltage and current is used on it, then it can easily go bad.
2. This device has a much wider and wider bandwidth compared to laser.
3. Here temperature depends on radiant output power and above wavelength.

What are Main LED materials

The main semiconductor materials that are used to manufacture LEDs:

  • Indium gallium nitride (InGaN): blue, green and ultraviolet high-brightness LEDs
  • Aluminum gallium indium phosphide (AlGaInP): yellow, orange and red high-brightness LEDs
  • Aluminum gallium arsenide (AlGaAs): red and infrared LEDs
  • Gallium phosphide (GaP): yellow and green LEDs

Types Of LED

Ever since the invention of LEDs, there has been a lot of change in its technology and a lot of variety is also being found, in which they have different properties and applications.

1.  Traditional inorganic LEDs: This type of LED is mainly the traditional form of diode which is also available since 1960s. They are manufactured using inorganic materials. The most commonly used compound semiconductors here are aluminum gallium arsenide, gallium arsenide phosphide, etc.

Here the color of these LEDs depends on which materials are being used.

There are many categories of these inorganic LEDs and it comes in many styles:

  • Single color 5 mm, etc. – This is the traditional LED package
  • Surface mount LEDs
  • Bi-color and multicolor LEDs – In these types of LEDs many individual LEDs are placed together and turn on through different voltages.
  • Flashing LEDs – which have a small time integrated into their package
  • Alphanumeric LED displays

2. High brightness LEDs: This is also a type of inorganic LED which is used for lighting applications. It is also similar to basic inorganic LED but has greater light output. These LEDs have to bear higher current levels and power dissipation to produce higher light output. These are mounted on top of the heatsink to remove unwanted heat. These lights are used in place of traditional lights.

3. Organic LEDs: Organic LEDs are a slightly advanced version of basic light emitting diode. These LEDs use organic materials as its name suggests. Organic types of LED displays are based on top of organic materials which are manufactured with the help of sheets and which provide a diffuse area of ​​light. Typically here a very thin organic material film is printed in the substrate which is made of glass. Then a semiconductor circuit is used so that the electrical charges can be brought to imprinted pixels, which helps in Glowing it.

In this way, LED technology is being improved gradually so that their efficiency level can be increased and they can be used more.

Applications of LEDs :

  • Indicator lights:
    They are used in Indicator lights. Which is used in two-state (ie, on / off), bar-graph, and alphabetic-numeric readouts.
  • LCD panel backlighting:
    Specialized white LEDs are used here in flat-panel computer displays.
  • Fiber optic data transmission:
    It is easy to perform modulation through them which allows to do wide communications bandwidth with minimal noise so that high-speed and accuracy are obtained.
  • Remote control:
    It is used in “remotes” in homes.
  • Optoisolator:
    They are used in optoisolator where it is easy to connect two stages without any unwanted interaction.

I sincerely hope that I have given you complete information about what is LED (Hindi) and I hope you have understood about what LED (Light Emitting Diode) is. I request all of you readers that you too should share this information in your neighborhood, relatives and friends, so that our awareness will be there and it will benefit everyone. I need your support so that I can convey more new information to you.

It has always been my endeavor that I always help my readers or readers from all sides, if you people have any doubt of any kind, then you can ask me irresponsibly. I will definitely try to solve those Doubts. What do you think this article is LED ? Tell us how you felt by writing a comment so that we too have a chance to learn from your ideas and improve something. Facebook

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