Page 151 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

LESSON 84 - 89 : Light Emitting Diode (LED)

Objectives
At the end of this lesson you shall be able to:
• explain the principle, construction, advantages & disadvantages of LED.

A Light Emitting Diode (LED) is a semiconductor device that emits incoherent narrow-spectrum light when
electrically biased in the forward direction. This effect is a form of electroluminescence. The color of the emitted
light depends on the composition and condition of the semiconducting material used, and can be near ultraviolet,
visible or infrared.
Symbol of LED

Working of LED:
LED is nothing but a type of diode. It also possesses a unique unidirectional property like general purpose
diode. It cannot and should not be used for the purpose of rectifying AC to DC. The simple LED circuit and LED
construction diagram is shown below.
LED CONSTRUCTION

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