the potentials of using led as commercial light

7/31/2019 The Potentials of Using LED as Commercial Light

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LED as Commercial Light Source

Physicsis UM

Prosacks UM

http://prosacksblog.blogspot.com


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Introduction

Q: What is LED?

A: LED Light Emitting

Diode


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Basic Principle of LED

Basically, an LED is just a special type of diode.

Diode is the simplest sort of semiconductor

device.

Most semiconductors are made of a poor

conductor that has had impurities (atoms of

another material) added to it.

The process of adding impurities is called

doping.


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A semiconductor with

extra electrons is called

N-type material.

In N-type material, freeelectrons move from a

negatively charged area

to a positively charged

area.


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A semiconductor withextra holes is called P-type material.

Electrons can jump from

hole to hole, moving froma negatively charged areato a positively chargedarea.

As a result, the holes

themselves appear tomove from a positivelycharged area to anegatively charged area.


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Now, lets see the basicworking principle of LED.


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At the junction, free

electrons from the N-

type material fill holes

from the P-typematerial. This creates

an insulating layer in

the middle of the diode

called the depletionzone.


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When the negative end

of the circuit is hooked

up to the N-type layer

and the positive end ishooked up to P-type

layer, electrons and

holes start moving and

the depletion zonedisappears.


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When the positive endof the circuit is hookedup to the N-type layerand the negative end ishooked up to the P-typelayer, free electronscollect on one end ofthe diode and holes

collect on the other. Thedepletion zone getsbigger.


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In the LEDs, the conductor material is typically

aluminum-gallium-arsenide (AlGaAs).

In pure aluminum-gallium-arsenide, all of the

atoms bond perfectly to their neighbors,

leaving no free electrons (negatively charged

particles) to conduct electric current.


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In doped material, additional atoms change

the balance, either adding free electrons or

creating holes where electrons can go.

Either of these alterations make the material

more conductive.

The interaction between electrons and holes

in this setup has an interesting side effect -- it

generates light!


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LED Lamp in CommercialUse


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LED Lamp in Commercial Use

LED lamps which are used comercially usuallyconsist of three parts, ie;


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The LED that emitting

light


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The lens which focusing

and aim that light.


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Heat sink draws heat

away from the lamp,

keeps them from

overheating.


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Now, lets look at some benefits of

using LED lamps as the major light

source in daily life.


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1) Longer lifetime

Good quality LED lamps

can have a lifetime up

to 50,000 hours.

Incandescent bulb (bulbwith filaments) 1,000

hours.

CFL (compact

fluorescent lamp)

10,000 hours.


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1) Longer lifetime


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2) Energy Efficient

Less energy needed to

light them, thus, cutting

cost, and environment

friendly.


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3) Non-hazardous

LED lamp do not contains mercury as in CFLand fluorescent lamp.

Safer to be used at home.


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Disadvantages

More expensive as the cost of production ishigh, however, in long-term usage, it isactually will save a lot of maintenance cost.

Vulnerable to high temperatures. If LEDcircuitry gets too hot, more current will passthrough thejunction mentioned earlier in thisarticle. When too much current coursesthrough the junction, it will cause irreversibleburn-out often called LED meltdown.


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Thank you for listening.


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References:

http://electronics.howstuffworks.com/led.ht

m

http://www.youtube.com/watch?v=vDYZxWN

Dm4k
http://electronics.howstuffworks.com/led.htmhttp://electronics.howstuffworks.com/led.htmhttp://www.youtube.com/watch?v=vDYZxWNDm4khttp://www.youtube.com/watch?v=vDYZxWNDm4khttp://www.youtube.com/watch?v=vDYZxWNDm4khttp://www.youtube.com/watch?v=vDYZxWNDm4khttp://electronics.howstuffworks.com/led.htmhttp://electronics.howstuffworks.com/led.htm

the potentials of using led as commercial light

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