Working of LED

A light-emitting diode LED means a semiconductor light source with two leads. Nick Holonyak, who was working for General Electric, came up with the idea for a light-emitting diode in 1962. LEDs are a specific form of diode with electrical characteristics comparable to PN junction diodes. As a result, the operation of an LED permits electricity to flow in one direction while blocking it in the other. The LED takes up a very small space, less than one mm2. LEDs have been employed in a variety of electrical and electronic devices. The functioning concept of the LED and its uses will be discussed in this article.

What is LED?

The LED, meaning typical light source in electrical equipment, is the light-emitting diode (LED). From your phone to massive advertising boards, it can be used. They’re most typically found in clocks and other gadgets that show time and data. In light-emitting diodes, the P-n junctions are heavily doped. An LED will emit colored light at a specified wavelength when forward bias, depending on the semiconductor material used and the doping amount. An LED is wrapped in a transparent cover to allow the emitted light to escape.

Construction of LED

Because LEDs are made up of three semiconductor material layers deposited over a substrate, they are straightforward to make and LED working is simple. These three layers are stacked one on top of the other, with the top region being P-type, the middle region being active, and the bottom portion being N-type. The holes are located in the P-type region, elections are located in the N-type region, and both holes and electrons are located in the active region.

There is no flow of electrons and holes when no voltage is provided to the LED. Hence it is steady. When the voltage is provided, the LED becomes forward biassed, causing electrons from the N-region and holes from the P-region to migrate to the active area. The depletion region is another name for this area. Because charge carriers such as holes have a positive charge whereas electrons have a negative charge, light can be created via polarity charges recombination.

Construction and the LED function play a crucial role, and eventually, it allows the use of the LED for different applications. Based on the usage, you can select the best suitable LED type.

How LED function?

• The LED function is very simple. Simply, a diode is a light-emitting diode. When the diode is forward biassed, the electrons and holes move quickly across the junction, constantly combining and removing one another. The electrons merge with the holes as they transition from n-type to p-type silicon, then vanish. As a result, it stabilizes the entire atom and provides a small burst of energy in a tiny packet of photons or light.

Working Principle of LED

The quantum theory underpins the operation of the light-emitting diode. According to quantum theory, energy is emitted from the photon when the electron descends from a higher energy level to a lower energy level. The energy difference between these two energy levels is equal to the photon energy. The current passes through the diode if the PN-junction diode is forward biassed.

The passage of holes in the opposite direction of current and the flow of electrons in the current direction cause current flow in semiconductors. As a result of the movement of these charge carriers, recombination will occur.

The electrons in the conduction band jump down to the valence band during recombination. Electrons emit electromagnetic energy in the form of photons when they leap from one band to the next, and the photon energy is equal to the forbidden energy gap. This is how LED functions. 

Conclusion

LEDs use less energy, have a low operating voltage, and have a long life and ruggedness. LEDs are used in various industries, such as optical communication, alarm and security systems, remote-controlled operations, robotics, etc. Its long-lasting capability, low power needs, quick response time, and fast switching characteristics are useful in various applications. LEDs have a wide range of applications and are frequently used in everyday life. When it comes to light efficiency, it’s important to remember that energy efficiency, and hence potential overall savings, are relative. When comparing the efficiency of various light sources, LED light sources are adequate. They are power-saving and give huge and sufficient light.