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Light Emitting Diode - Meaning, Principle, Uses, Types, FAQs

Light Emitting Diode - Meaning, Principle, Uses, Types, FAQs

Edited By Vishal kumar | Updated on Sep 24, 2024 12:45 PM IST

Light Emitting LED Diode Working

LED Definition and LED meaning: In the semiconductor, electrons recombine with electron holes to produce energy in the form of photons. The energy required for electrons to pass the semiconductor's band gap determines the hue of light (equivalent to the energy of photons). The white light can be produced by several semiconductors, or by the luminous phosphorus coating, on the semiconductor device.

The first LED, which appeared as functional electrical components in 1962, emitted low-intensity infrared (IR) light. Remote-control circuits, such as those found in a wide range of consumer gadgets, utilise infrared LED. The original visible-light LED had a low intensity and were only available in red. Modern LED come in visible, ultraviolet (UV), and infrared wavelengths and can produce high, low, or intermediate light output.

Early LED were commonly employed as indicator lamps and in seven-segment displays, replacing small incandescent bulbs. Recent technological advances have resulted in high-output white light LED that can be utilised to illuminate interiors and outdoor spaces. LED have spawned a slew of novel displays and sensors, and their rapid switching rates are important in sophisticated communications.

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What is LED light emitting LED diodes working?

LED stands for Light Emitting Diode and it is a device which emits light by flowing a current to the positive-negative junction like a semiconductor laser. It emits various wavelength lights in the ultraviolet, visible and infrared regions, corresponding to its band gap energy.

Circuit of a Light emitting LED diode working

Simple LED circuit with current limiting resistor

LED circuit diagram

LED symbol and LED diagram (LED circuit diagram)

In circumstances where traditional circuits, such as a standard diode are employed, the LED also have a specified voltage drop forward. The voltage drop is determined by the LED's current, the colour of the light generated and other factors. The voltage drop varies between 1.5V and 2.5V for currents ranging from 10 to 50 mA.

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Working of LED and Principle of LED

The LED is connected in the forward bias, which allows the current to flow in the forward direction. The flow of current is because of the movement of electrons in the opposite direction. The recombination shows that the electrons move from the conduction band to the valence band and they emit electromagnetic energy in the form of photons. The energy of photons is equal to the gap between the valence and the conduction band.

The energy is released in the form of heat in conventional LED diode workings. However, with an LED, the release of energy in the form of photons would result in the emission of light energy. The process is referred to as electroluminescence.

How much energy is discharged in the form of light in LED is determined by the forbidden energy gap. As a result, the light colour and visibility cannot be altered based on its wavelength. By doping the light with various contaminants, the colour and wavelength of the light emitted may be determined.

Uses of LED

LED are used in a variety of industries, such as optical communication, alarm and security systems, remote-controlled operations, robotics, and so on. Because of its long-lasting capability, low power needs, quick response time, and fast switching capabilities, it is uses of LED in a variety of applications. The following are some of the standards that LED adheres to:

  1. Backlighting for televisions
  2. Frequently seen in exhibits
  3. Applied to automobiles
  4. LED are utilised in light dimming.

NCERT Physics Notes:

Types of LED Light emitting LED diode working

  1. Gallium Arsenide (GaAs) is an infrared semiconductor.
  2. Red to infrared, orange Gallium Arsenide Phosphide (GaAsP).
  3. High-brightness red, orange-red, orange, and yellow Aluminium Gallium Arsenide Phosphide (AlGaAsP).
  4. Gallium Phosphide (GaP) comes in three colours: red, yellow, and green.
  5. Green Aluminium Gallium Phosphide (AlGaP).
  6. Green, emerald green gallium nitride (GaN).
  7. Near-ultraviolet gallium indium nitride (GaInN) — bluish-green and blue.
  8. As a substrate, Silicon Carbide (SiC) is blue.
  9. Blue Zinc Selenide (ZnSe).
  10. AlGaN (Aluminium Gallium Nitride) – ultraviolet.

LED have a wide range of shapes and sizes and colours. The colour of the plastic lens is frequently, but not always, the same as the colour of the light emitted. Infrared LED, for example, are frequently made of purple plastic, whereas most blue gadgets have colourless housings.

Light-emitting LED diode working

LED construction

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Frequently Asked Questions (FAQs)

1. What is the duration of a light emitting LED diode working?

The rated life of many LED is up to 50,000 hours. This is roughly 50 times longer than an incandescent bulb, 20-25 times longer than a halogen bulb, and 8-10 times longer than a CFL bulb. A 50,000 bulb will survive more than 11 years if uses of LED 12 hours a day.

2. What is the principle of operation of a light emitting LED diode working?

Principle of Operation: A light-emitting diode (LED) is a semiconductor light source with two leads. When triggered, it is a p–n junction diode that emits light. Electrons are able to recombine with electron holes within the device when a proper voltage is given to the leads, releasing energy in the form of photons.

3. What are some of the drawbacks of LED lighting?

Drawbacks of LED lighting are:

  1. High setup costs.

  2. Compatibility with transformers

  3. Colour shift throughout lamp life is a possibility.

  4. Standardization of performance has not yet been streamlined.

  5. Overheating can shorten the life of a lamp.

4. What is the power consumption of LED?

A light bulb's electricity consumption is measured in KWh. Over the course of a 15,000-hour lifespan, an LED bulb consumes 127.5KWh. Incandescent bulbs that are uses of LED for 15,000 hours (theoretically; incandescent bulbs do not last that long) consume 900KWh of electricity.

5. What is the purpose of a light emitting LED diode working?

LED (Light emitting LED diode workings) transform electrical energy directly into light, as opposed to traditional light sources that convert electrical energy into heat and subsequently into light, resulting in efficient light creation with minimal electricity waste.

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