What is LED Light bulb and How LED Light Works?

The bulb was a wonderful invention of science and LED is the future. LED means ‘Light Emitting Diode’. It is also called ‘Luminous Efficacy’ on the market. A kind of solid-state lighting device which turns electricity into light more efficiently. In 1962, Nick Holonyak, Jr., invented the first visible-spectrum Led in the form of red diodes. As LED is much convenient to use, it has numerous uses. Like aviation lighting, automotive headlamps, Tailgate Light Bar, advertising, general lighting, traffic signals, camera flashes, lighted wallpaper, horticultural grow lights, and medical devices.

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What is LED Light Bulb?

Light Emitting Diode’ is called LED in general. This kind of bulb is approximately 90% more efficient than the traditional kinds of bulbs along this less energy consumed also. The main part of this bulb is a microchip which makes it environmentally friendly compared to others. The longevity of LEDs is around 60,000 hours. They are unbreakable and cool to touch. LED has an efficacy of 683 lm/W where a 60- to 100-watt incandescent bulb has an efficacy of 15 lm/W and an equivalent CFL has an efficacy of 73 lm/W.

How LED Light Works?

The working principle of LED is very simple which is based on quantum theory. The quantum theory says that when the electron comes down from the higher energy level to the lower energy level then, the energy emits from the photon. The photon energy is equal to the energy gap between these two energy levels. When the PN-junction diode will be in forward-biased, then the current will flow through the diode. As a result, two semiconducting materials get nicely arranged between their electrodes. 

The energy band-gap between the semiconductor used is crucial for the wavelength of the light because it determined the color of the light. When a suitable voltage is applied to the leads, electrons start to rejoin with electron holes within the device, releasing energy in the form of photons which is the visible part of the spectrum of light. LEDs basically made of aluminum-gallium-arsenide (AlGaAs) because of the strong nature of bonding of the atoms of this material. The high demand for these materials was because of their ability to produce photons. By Doping some impurities are being added with pure semi-conductor, extra atoms are introduced which effectively disturb the balance of the material and creates the desired type of material.

There are two types of semiconductors which are used in LED.

  1. P-type – Has extra holes or as they are more commonly known, extra particles with a positive charge.
  2. N-type – Has extra electrons or extra particles with a negative charge.

Step by Step Working Procedure:

How LED Works

The above diagram shows how the light-emitting diode works and the step-by-step process of the diagram is discussed below.

  • From the diagram, it is cleared that in the first step, the N-type silicon is in red and full of the electrons (black circles).
  • In the second step, the P-type silicon is in the blue color which is full of holes (white circles).
  • In the next step, the p-n junction becomes forward biased because of applying a specific voltage. As a result, it pushes the electrons from n-type to p-type and the holes in the opposite direction.
  • Then at the junction, electron, and holes get combined.
  • In the final stage, the photons are given off which causes visible part of the spectrum of light as the electrons and holes are recombined.

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Types of LED Light Bulbs

There are mainly 3 types of LEDs depends on the uses of these bulbs. In this part, the wattage of the bulb is the key factor because it determines the place where the bulbs should be used.

1. Miniature LEDs (Chip, Nano & Pico LEDs)

These LEDs are mainly used in remote controls, calculators, and mobile phones as indicators as they are the most common types of LEDs and also very small in size and always available in single color or shape. They don’t need any device to cool or control. As a result, they can be directly used on any circuit board. The sizes are generally (Chip- 3.2mm, Nano- 1.6mm, Pico- 1mm).

2. High Power LEDs

Because of the ability to produce a greater number of lumens than standard varieties it is also called High-output LEDs. Some heat-absorbent material is always connected to these LEDs because they generally become hot. They are mainly used in headlamps, car or motorbike headlights, several scientific, industrial, and mechanical applications.

3. Application-Specific LEDs

These LEDs can be again divided into few more subcategories. Such as-

I. Lighting LEDs

They can be of several sizes and shapes according to their use. They can be found in single, LED bars or LED strips. So, they are also called illuminators.

II. Alphanumeric LEDs

They are only used to display any alphabet or numeric number. There are 3 kinds of alphanumeric LEDs. They are-

  • 7- segment– They can display a specific set of letters an all the numbers.
  • 4- and 16- segment- They can show all numbers along with the entire Roman Alphabet in the upper case.
  • Matrix- They can display all kinds of alphabets in both upper and lower cases. Also able to produce a wide range of symbols and numbers.

III. RGB (Red Green Blue) LEDs-

These LEDs are made of red, green, and blue emitters which makes them able to produce every color of light. They are used in the video display, indicators, and lighting.

IV. Bi-color and Tri-color LEDs

There are 2 light-emitting dies, 3 leads, and a cathode or an anode. Because their inverse properties mean when one is backward and one is forward, which in turn, only one die can be on at one time. These LEDs can also change color.

V. Flashing LEDs

They are also like standard LEDs but there is an integrated circuit (IC) alongside the LED. So that it can produce an appropriate light or specific frequencies. They are directly connected to the power supply without any series resistor. They are mainly used to give signs, in cars, or any electronic gadgets. 


The invention of the bulb made the life of people so convenient. But after the appearance of LEDs, it has made a magnificent change in the life of people because of the benefits of the LEDs. People are having a better environment for reading, writing. Playing video games or watching videos has become more comfortable. At the end of the day, it helps people to save a huge amount of money by saving energy.

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