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Light-emitting diode


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Light Emitting Diodes


An Introduction to Light-Emitting Diodes (LEDs) - Electronics for Absolute Beginners

A light-emitting diode (LED) is a semiconductor light source that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device.
  • Discoveries and early devices 

  • Initial commercial development 

  • Blue LED 

  • White LEDs and the illumination breakthrough 

  • Physics of light production and emission 

  • Blue and ultraviolet 

  • White 

  • RGB systems 

  • Phosphor-based LEDs 

  • Other white LEDs 

  • Organic light-emitting diodes (OLEDs) 

  • Miniature 

  • High-power 

  • Flashing 

  • Bi-color 

  • RGB tri-color 

  • Alphanumeric 

  • Digital RGB 

  • Filament 

  • Chip-on-board arrays 

  • Power sources 

  • Electrical polarity 

  • Safety and health 

  • Advantages 

  • Disadvantages 

  • Applications 

  • Indicators and signs 

  • Lighting 

  • Data communication and other signalling 

  • Machine vision systems 

  • Biological detection 

  • Other applications 

  • Key challenges 

  • Perovskite LEDs (PLEDs) 

  • Two-way LEDs