LED Lightbulb working principle

We always come across LED Lightbulb in our homes and offices. We also know that LED bulbs consume less electricity. So, we need to pay less light bills. But the working of LED Lightbulbs is complex. We will explain here about its working in detail.

LED focus bulb
LED focus bulb

First of all, LED is a semiconductor light source. This light source emits light when a current passes through it. The electrons in semiconductor recombine with electron holes. This process releases energy in the form of photons in the surrounding. These photons are nothing but the light.

Furthermore, the energy requires to cross the band gap in semiconductors determines the colour of the emitting light. We have various colours in LED Lightbulbs. So, LED’s are more colourfull, efficient and bright. Hence, larger population all around the world now use LED’s in-home.

Working of LED Lightbulb

First of all, light travels in the form of particles having zero mass. We call them photons. The light is nothing but the release of energy as electrons move within the orbit of the atom.

Furthermore, the LED’s are made up of aluminum, gallium, and arsenide. The short form is (AlGaAs). This material has a strong bond of atoms. Hence it is more on a stable side. Without free electrons, the conduction of electricity is not possible.

So, to make this material unstable we need to introduce impurity. This process is doping. Hence, by introducing extra atoms the material becomes unstable. These introduced atoms by impurities either introduce free electrons or suck out existing electrons in orbit. Thus it creates holes in the orbit.

Furthermore, the above condition also provides the base for transferring electrons from anode to cathode. So, basically nonconductive material becomes conductive when we introduce impurity. Hence, the intensity of the light depends upon the emitted photons.

The photon emission further depends upon energy release from electrons as they jump from higher to lower orbits and vice versa. All this happens in a semiconductor material.

The electrons in LEDs jump from higher orbits to lower orbits releasing energy. So, higher the distance between orbitals greater the intensity of the light. Actually, the whole process is a bit complex.

Application of LED Lightbulbs

The application of LED is very diverse in nature. The automotive industry now heavily relies on LED Headlamps. The aviation lighting, railway & traffic lights, general lighting, advertising, home, and industrial lighting, camera flashes, etc. all use LED’s in different ways.


The LED Lightbulbs are highly efficient when we compare them with traditional lights. We can simply emit many colours from the same light source. The LED’s have very little warm up time. The size of the LED is very small. They also have a long on-off cycle time.

In addition, The LED’s emit very cool light and almost no heat. The lifetime of these lights is long and they are not prone to failures. You can easily dim them as well as per your needs. In addition, they have a very clear focus and they are shockproof as well.


The functioning of LED Lightbulbs largely depends on the operating environment. The very high and very low-temperature results in a higher failure rate. The object colour may change as they have a poor rendering of green and red surfaces.

In addition, they also require a regulated voltage. Variation in voltage levels is not advisable. Large outdoor use of LED light creates light pollution. Higher voltage leads to higher heating and this is particularly harmful for LED’s lifetime.

Furthermore, these lights have a high impact on insects. These lights attract more insects than traditional light bulbs. LED Lightbulbs in parallel connection also lead to LED failure. This is because the forward voltage has manufacturing tolerance.

In conclusion, LED Lightbulbs are more efficient and can reduce greenhouse gas emission but we should not neglect the disadvantages as well.

Image courtesy: Philips

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