It’s consists of a semiconducting material which emits light when current is passed through it. It can emit light of different colour. When voltage is applied, it causes the hole present in p-side and the electron present in the n-side to move towards the space charge region. When hole and electron combine it emits photon. The wavelength of the photon(i.e colour of the light) depends on the band gap energy of the semiconductor used. An LED is shown below:
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| LED |
It has lot of advantages over the incandescent lamp. LED is more efficient, less power consuming; less heat emitted etc. therefore it is ideal for electronic circuits since it consumes less power.
The shorter terminal is usually the negative terminal and the longer terminal is the positive terminal. The current passing through it must not exceed the limit stated by the manufacturer.
LED has many applications such as lighting, monochrome Message Boards, Bar Code Readers, color & Money Sensors etc.
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