What are LEDs

A light-emitting diode (LED) is a semiconductor device that emits visible light when an electric current passes through it. led chipThe light is not particularly bright, but in most LEDs it is monochromatic, occurring at a single wavelength. The output from an LED can range from red (at a wavelength of approximately 700 nanometers) to blue-violet (about 400 nanometers).

An LED consists of two elements of processed material called P-type semiconductors and N-type semiconductors. These two elements are placed in direct contact, forming a region called the P-N junction. In this respect, the LED resembles most other diodetypes, but there are important blue-leddifferences. The LED has a transparent package, allowing visible energy to pass through. Also, the LED has a large PN-junction area whose shape is tailored to the application.

Benefits of LEDs compared with incandescent and fluorescent illuminating devices, include:

  • Low power requirement: Most types can be operated with battery power supplies.
  • High efficiency:Most of the power supplied to an LED is converted into radiation in the desired form, with minimal heat production.
  • Long life:When properly installed, an LED can function for decades.
  • Typical applications include:
  • Indicator lights:These can be two-state (i.e., on/off), bar-graph, or alphabetic-numeric readouts.
  • LCD panel backlighting:Specialized white LEDs are used in flat-panel computer displays.
  • Fiber optic data transmission:Ease of modulation allows wide communicationsbandwidth with minimal noise, resulting in high speed and accuracy.
  • Remote control:Most home-entertainment “remotes” use IREDs to transmit data to the main unit.
  • General Lighting : Today LED’s are also used as an efficient replacement to a typical light source