presentation on light emmiting diodes, their uses and applications

1. LIGHT EMITTING DIODE(LED)

2. WHAT IS LED?
A light-emitting diode
(LED) is a
semiconductor device
that operate on the
principle of
electroluminescence,
that is it emits light
when an electric
current flows through it

3. LED SYMBOL

4. LED CIRCUIT DIAGRAM

5. HOW DOES A LED WORK?
 The LED works in the forward biased mode
 When the diode is forward biased, the minority electrons are
sent from p n while the minority holes are sent from n → p.
 At the junction boundary, the concentration of minority
carriers increases. The excess minority carriers at the junction
recombine with the majority charges carriers.
 The energy is released in the form of photons on
recombination.

6. WHAT DETERMINES THE COLOUR OF AN
LED?
The color of an LED is determined by the material used in
the semiconducting element. - The two primary
materials used in LEDs are aluminium gallium indium
phosphide alloys and indium gallium nitride alloys.
Aluminium alloys are used to obtain red, orange and
yellow light
Indium alloys are used to get green, blue and white light.

7. PROPERTIES OF LASER LIGHT
Monochromatic
Directional
Coherent

8. TYPES OF LED
Miniature LEDs
High-Power LEDs
Flash LED
Bi and Tri-Colour
Red Green Blue LEDs
Alphanumeric LED
Lighting LED

9. USES OF LED
Used for TV back-lighting
Used in displays
Used in Automotive
LEDs used in the dimming of lights

10. ADVANTAGES | DISADVANTAGES
It is cheap
It is portable
it is reliable
It is not fragile
It consumes very
little power
It can get damage
under high Voltage
Little effective in
wide-area
Causes backward
heat dissipation

11. Thank you