Light-emitting diodes (LEDs) are ruling the world of electronics because of their versatility and efficiency. LEDs are tiny lights that work together to form anything, from the numbers on digital clocks to images on the television screens. Since light-emitting diodes are small in size, it is easy to fit them in an electric circuit. These light sources are energy-efficient which means that they consume less electricity as compared to filament bulbs. LEDs are quickly replacing incandescent bulbs throughout the world because of their bright light, long-life, and cost-effectiveness. This article focuses on the working of this amazing invention.
LEDs are everywhere these days, they are used for illumination and decoration.
An LED consists of a semiconductor that gives off light when current passes through it the process is called electroluminescence. A semiconductor is a material that can’t conduct electricity as well as a metal conductor. The conductivity of a semiconductor lies somewhere between that of a conductor and an insulator. A popular example of semiconductors is Silicon.
Due to the way semiconductors are designed, the current flows in a single direction. This uni-directional flow of current across the diode is because of high resistance offered by it in one particular direction. Current can’t flow in the presence of high resistance thus it flows only in the direction that doesn’t have resistance.
An LED contains a combination of two types of semiconductors; a p-type semiconductor and an N-type semiconductor.
An N-type semiconductor is made by adding an impurity to the semiconductor by a process called doping. The impurity here refers to an element that can provide electrons. Common examples of such elements are phosphorus, antimony, and arsenic. Such impurities are called donor impurities and provide free-electrons to the semiconductor. Doping enhances the electrical conductivity of the semiconductor.
A p-type semiconductor is one that has more holes than electrons. This type of semiconductor is made by doping the host material with atoms that can accept electrons such as Boron or Gallium. Holes refer to spaces created in the atomic orbits that electrons occupy. Holes are positively charged and an abundance of these positively charged holes in the P-type semiconductor gives it its name.
As mentioned earlier, an LED consists of a P-type semiconductor and an N-type semiconductor. A region where both types of semiconductors are attached is called the PN junction. When a PN junction is formed, electrons from the N side fill up some of the holes on the p side. Thus, holes also appear to move from the p side to the n side.
This movement of electrons leads to the formation depletion zone that doesn’t have holes or electrons because all the holes have electrons in them. Since there are no charge carriers in the depletion zone electricity can’t flow through it.
Now that you understand the components of the LED, we can discuss how electricity is actually produced in the LED. In order to get your diode to emit light, you have to connect its P-side with the positive end of the circuit and its N-side with the negative end of the circuit. Now what happens is that the free electrons present on the N-side are repelled by the negative electrode. This results in a movement of electrons towards the positive electrode. Similarly, the holes on the P-side move towards the negative end of the circuit.
When there is a high voltage difference between the electrodes, the depletion zone vanishes. This happens because when the electrons inside the depletion zone are faced with the high voltage they can no longer stay in their holes. The voltage applied to the diode knocks them out of their holes are they start moving freely again.
This flow of current releases energy in the form of photons. Photons are packets of energy that are the basic units of light. In an LED majority of the energy comes off as light while only a minute amount is dissipated as heat.
The Other LEDs
The term LED is very loosely used for the visible light-emitting diode. In reality, diodes that give off visible light are not the only types of diodes used in electronics. Whether an LED would emit visible light or not depends on the type of semi-conductor used in it. A silicon LED, for example, doesn’t produce visible light, it produces light that falls in the infrared spectrum that is used in remote controls.
Different types of LEDs emit light of all colors in the visible spectrum. This makes these tiny bulbs an interesting thing to use. LED neon flexes are made using LEDs of different colors to help people advertise their business in a captivating way. Similarly, the color feature makes the light-emitting diodes a go-to for making decorative lighting.
LEDs are not only cost-effective but have a host of other benefits as well. They do not emit any harmful rays and are very resilient against tough weather. The lack of mercury in them makes them totally recyclable which is great for the environment. They also have a much longer life-span than other kinds of lights. Due to the process explained above, LEDs use 95% of the energy that enters them, which means brighter light and less wastage. Shift to LEDs today for a brighter and safer illumination experience.