Explain the working of LED and what are its advantages over conventional in can descent low power lamps.

Explanation

Light emitting diode ( LED) `:` It is a photoelectronic device which converts electrical energy into light energy.
It is a heavily doped p-n junction diode which under forward bias emits spontaneous radiation. The diode is covered with a transparent cover so that the emitted light may be come out.
Working `:` When p-n junction diode is forward biased , the movement of majority charge carriers takes place across the junction. The electrons move from n-side to p-side through the junction and holesmove from p-side to n-side.
As a result of it, concentration of majority carriers increases rapidly at the junction.
When there is no bias across the junction , therefore there are excess minority carriers on either side of the junction, which recombine with majority carriers near the junction.
On recombination of electrons and hole, the energy is given out in the form of heat and light.
Advantages of LED's over in can descent lamp`:`
(1) LED is cheap and easy to handle.
(2) LED has less power and low operational voltage.
(3) LED has fast action and requires no warm up time.
(4) LED can be usedin burglar alarm system.