LIGHT EMITTING DIODES (LED) BY AARTHI.M (221710303001)
WHAT IS LED? It is a p-n junction diode that emits light when activated.When suitable voltage is being applied to the LED electrons are able to recombine with the electron holes within the device releasing energy in the form of photons. This effect is called electroluminescence and the colour of the light is determined by the energy band gap of the semiconductor.The first typical LED was of low intensity and was limited to red.Modern LED are available across the visible,ultraviolet and infrared wavelengths,with very high brightness. WORKING PRINCIPLE The p-n junction diode can convert absorbed light energy into proportional electric current.The same process is reversed here. this process is called electroluminescence which can be defined as the emission of light from the semiconductor under the influence of an electric field.the charge carriers recombine in forward bias p-n junction as the electrons flow from the N region and recombine with the holes existing in the
