LEDs (light emitting diodes) are tiny semiconductor devices that emit light when electric current passes through them. They are found in many electronic devices to provide numbers, images, and indicators. Unlike incandescent bulbs, LEDs have a much longer lifespan and don't get hot. Depending on the material used, LEDs can produce light in the infrared, visible, or ultraviolet spectra. They are becoming increasingly popular for lighting and displays due to their efficiency and compact size.

1. LED
LIGHT EMITING DIODE

2. WHAT IS LED?
Light Emitting Diodes,
commonly called LED’s, are
real unsung heroes in the
electronics world.

3. • They do dozens of different jobs and are found
in all kinds of devices.
• Among other things, they form numbers on
digital clocks, transmit information from
remote controls, light up watches and tell you
when your appliances are turned on.
• Collected together, they can form images on a
jumbo television screen or illuminate a traffic
light.

4. • Basically, LED’s are just tiny light bulbs that fit
easily into an electrical circuit.
• But unlike ordinary incandescent, they don’t
have a filament that will burn out, and they
don’t get especially hot.
• The lifespan of an LED surpasses the short life
of an incandescent bulb by thousands of
hours.
• Tiny LED’s are already replacing the tubes that
light up LCD, HDTV’s to make dramatically
thinner televisions.

5. WHAT IS HAPPENING?
• The hole exist at a lower
energy level than the free
electrons.
• An electron releases an energy
when it drops from a higher
orbital to a lower one. This
energy is released in the form
of a photon.
• The energy is emitted in the
form of light photon.
• The size of the electrons fall
determines the energy level of
the photon, which determines
its color.
• A bigger fall produces a
photon with a higher energy
level and therefore a higher
light frequency.

6. DIODE VS LED
• In a ordinary diode, the
semiconductor material
itself ends up absorbing a
lot of the light energy.
• LED’s are specially
constructed to release a
large number of photons
outward.
• They are housed in a
plastic bulb that
concentrates a the light in
a particular direction.

7. INFRARED LED’s
• You can only see the photons when the diode is
composed of certain material.
• The atoms in a standard silicon diode, for
example, are arranged in such a way that the
electron drops a relatively short distance. As a
result, the photon’s frequency is so low that it is
invisible to the human eye.
• It is in the infrared portion of the light spectrum.
• Infrared LED’s are ideal for remote controls.

8. VISIBLE LED’s
• Visible LED’s are made of materials
characterized by a wider gap between
the conduction band and the lower
orbitals.
• The size of the gap determines the
frequency of the photon. In other
words, it determines the color of the
light.
• Visible LED’s are growing in
popularity and use thanks to their
long lifetimes and miniature size.
• Depending on the materials used in
the LED’s, they can be built to shine
in infrared, ultraviolet, and all the
colors of the visible spectrum in
between.

9. • LED’s are available in red,
orange, amber yellow,
green, blue and white. Blue
and white are much more
expensive than the other
colors.
• The cost of manufacturing
the product varies
depending on the type of
semi-conductor used.
• White LED’s are the most
expensive because red,
green and blue are
combined together to make
a white LED.

10. THANK
YOU!