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What is LED and how does it work?

What is LED and how does it work?

What is LED and how does it work?

Do you know what is LED ? Have you used it? Do you know how this works? If you know the answers to these questions then it is a very good thing and if not then there is nothing to panic at all. Because today we are going to get complete information about this in this article.

LED or it is also called Light-Emitting Diode. It is a semiconductor device that emits light when current or electricity is passed through it. Here light is produced only when the internal particles (which are electrons and holes) combine with each other in the same semiconductor material.

Since here light is generated from the 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 lot of people.

So that’s why today I thought that why should you not be provided complete information about what is LED, so that you people also know about this new invention. So without delay let’s start and know what is LED and how it works.

What is LED

This is the full form of LED Light Emitting Diode. This is a very latest invention and it is being used the most today. These magic light bulbs are used in a very wide range of applications, from your cell phone to large advertising display boards.

You can watch it anywhere. Today its popularity and applications are increasing day by day because it has some very good properties like this. Especially LEDs are very small and with this they use very little power.

We can place this LED in the category of “active” semiconductor. We can also compare this diode with the normal general purpose diode, but the biggest difference in it is that it has the ability to emit different types of light.

If both the terminals (anode and cathode) in this LED are connected to a voltage source in its correct polarity, then it can produce light of different colors, along with it also depends on the semiconductor substance located in it. does.

The bright light produced when LED is lit is monochromatic and has 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 called IRED (infrare-emitting diode).

An LED mainly consists of two elements of the 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 P-N junction.

They are similar to other diodes but have a transparent package that helps the visible or IR energy to pass through.

History of LED

For the first time in the year 1907, LED was brought to this world when elecluminescence was discovered by British scientist H.J.Round in Marconi Labs.

After that in 1961, when Gary Pittman and Robert Biard were doing their experiments at Texas Instruments, they discovered that gallium arsenide emits infrared radiation when exposed to electrical current, which they later named infrared LED. Patent made.

After that, the first visible light LED (red) came in the year 1962. It was developed by Nick Holonyak Jr. By when he was working at General Electric. That’s why Holonyak is also called the “father of the light-emitting diode”.

Then in 1972, M. George Craford, who was once a student of Holonyak, introduced yellow LED first and he increased the light output of red and red-orange LEDs by a factor of 10 which was at that time. It was a great achievement.

Working Principle of LED

A light-emitting diode is a two-lead semiconductor light source. It is a p–n junction diode which emits light when activated. When a suitable voltage is applied to its leads, the electrons in it 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.

Complete Working Principle of LED

The material used by LEDs is basically aluminum-gallium-arsenide (AlGaAs). In their original state, the atoms of this material are very strongly bonded. Here it is impossible to conduct electricity due to the absence of free electrons.

Here an impurity can be added, also called doping, where extra atoms are introduced, so that the balance of the material is disturbed. By adding these impurities, those that are in the form of additional atoms either provide

Free electrons in the (N-type) system or already existing electrons are removed from these atoms (P-type), creating “holes” from atomic orbits.

In both these methods the materials become very conductive. Here electrons in N-type of material are able to travel from anode (positive) to cathode (negative) under the influence of electric current and vice versa in P-type of material. According to the semiconductor property, the current never travels in the opposite directions in these respective cases.

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

As we know that in order to move the electron from the lower orbital to the higher orbital, its energy level is increased. In the same way, if the energy level of the electron is reduced to move it from higher orbital to lower orbital.

And these phenomena are used properly in LEDs. In p-type doping, the electrons in the LEDs move from higher orbitals to lower orbitals, releasing their energy in the form of photons, which is light. Orbitals, which are farther away from each other, emit light with more intensity.

In this process different colors are produced according to different wavelength in LEDs. Therefore, what kind of light will be emitted from the device depends on which type of semiconductor material is used.

Infrared light is produced by using Gallium Arsenide (GaAs) as a semiconductor. Red and yellow light are produced by using Gallium-Arsenide-Phosphorus (GaAsP) as a semiconductor.

Red and green light are produced by using Gallium-Phosphorus (GaP) as a semiconductor.

LEDs Advantages

Let us now know about the advantages of LEDs: –

  • Very little voltage and current is required to light the LED.
  • Voltage range – 1 to 2 volts, Current – ​​5 to 20 milliamperes.
  • Here the total power output is very less than 150 milliwatts.
  • Here the response time is very short – which is only 10 nanoseconds.
  • This device does not require any heating and warm-up time.
  • Their size is very small and it is lightweight.
  • They have very rugged construction and hence can tolerate shocks and vibrations.
  • The life of LED is more than 20 years.

LEDs Disadvantages

Let us now know about the disadvantages of LEDs: –

  • If even a little more voltage and current is used on it, then it can easily get damaged.
  • This device has a much wider and wider bandwidth in comparison to laser.
  • Here the temperature depends on the radiant output power and wavelength

Types of LEDs

Ever since the invention of LEDs, there has been a lot of change in its technology and its 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 they come 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 put together and they are turned on through different
  • voltages.
  • Flashing LEDs – In which small time is integrated in their package
  • Alphanumeric LED Displays

2. High Brightness LEDs

This is also a type of inorganic LED which is used for lighting applications. This is also similar to the basic inorganic LED but it has a greater light output.

These LEDs have to tolerate higher current levels and power dissipation to produce higher light output. These are mounted on top of the heatsink so that unwanted heat can be removed. These lights are used in place of traditional lights.

3. Organic LEDs

Organic LEDs are a slightly advanced version of the basic light emitting diode. Organic materials are used in these LEDs as its name suggests. Organic type of LED display is based on organic materials which are manufactured with the help of key sheets and which provide a diffuse area of ​​light. Here usually a very thin organic material film is printed in the substrate which is made of glass.

Then a semiconductor circuit is used to bring the electrical charges to the imprinted pixels.

what did you learn today

I sincerely hope that I have given you complete information about what is LED (LED ) and I hope you people have understood about what is LED (Light Emitting Diode).

I request all of you readers that you also share this information in your neighborhood, relatives, your friends, so that there will be awareness among us and everyone will benefit a lot from it. I need your cooperation so that I can pass more new information to you guys.

It has always been my endeavor that I should always help my readers or readers from all sides, if you people have any doubt of any kind, then you can ask me without any hesitation. I will definitely try to solve those doubts. You like this article What is LED? How did you feel, do tell us by writing a comment so that we too get a chance to learn something from your thoughts and improve something.

Aslam Mathakiya

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