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working of different LAMPS

Presentedby

Nagaraju(L09EE140)

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INTRODUCTION:

Light plays an important part inmodern day to day life ,because allactivities to human beings ultimately

depend up on the light .

moreover ,where natural light is notavailable, use artificial light is made.

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SOURCES OF LIGHTS :

LIGHT

NATURALEX:SUN,STAR

NON ELECTERICALEX:CANDLE,

KEROSENE LAMPS

ELECTRICALEX:INCANDESCENT

LAMP

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WHAT IS LIGHT ?

Light is an electromagnetic radiation.

A hot body about 500 c to 800 cbecomes a red hot & about 2500c to3000c the body becomes white hot.

In both the cases a part of radiationis in the form of heat and the rest inthe form of light.

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PRODUCTION OF LIGHT :

It is produced by electronicoscillations with in the atom it self.

If two electrodes are placed in gaspotential difference applied betweenthem , the free electrons will beattracted toward the anode with

velocity depending on the potentialgradient.

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PRODUCTION OF LIGHTINCLUDES:

Elastic collision.

Excitation .

Ionization . Incandescence.

Fluorescence &phosphorescence.

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Requirements of good lighting:

Illumination level

Absence of glare

Absence of contrast Shadows

Colour rendering

Ease of maintenance

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Types of lamps:

lamps

Arc lampsIncandescent

lampsGas discharge

lamps

Sodium vapourlamp

Mercury vapourlamp

Neon lamps Fluorescent lamps

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Arc lamps:

An arc is strucked between two carbonrods and white light will be produced whentwo rods are separated slightly.

The arc is maintained by transfer ofcarbon particles from +ve rod to ve rod.

The efficiency of the lamp is 9lumens/watt.

It mainly used for outdoor use.

Disadvantage of lamp flicker &noise.

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Incandescent lamps (or)filament lamps:

It works on the principle of incandescene.

They have long life of about 1000 hours ata specified filament temperature of 2700c

and voltage is 230v. The bulb is filled with an inert gas

(argon,nitrogen,neon) to reduce theevaporation of the filament.

tungsten filament can run at temperatureranging from 2500c to 3000c

Efficiency of lamp is 12 lumen/watt.

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Gas discharge lamps:

Electric current is passed through agas or vapour.

It works on the principle of excitation& ionisation.

The colours of light produceddepends on the nature of gas orvapour.

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Sodium vapour lamp: It consists of an inner tube of u-shaped

filled with sodium and inert gas neon orargon & is fitted two elements.

This lamp is used horizontally to help the

sodium when spread along the tube. When sodium vaporizes the colour

changes from red to yellow. The efficiency is about 50-70 lumen/watt

for a 140w and life is 3000 working hours. These lamps are used for street lighting,

high lighting.

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Mercury vapour lamp:

The inner tube contains argon gas and afew mercury drops and two mainelectrodes in the from of oxide coatedcoils.

The operation takes about 5-7 minutes.

It emits greenish blue light.

The efficiency of lamp is 30-40

lumens/watt. It is mounted vertically. It is used for

industrial lighting, ports,shopping centre.

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Neon lamps:

This lamp consists of a glass tubecontaining neon gas with a small amountof helium.

This lamp gives orange pink colour.

It requires 110v for A.C &150v for D.C

Efficiency of lamp is 15-40 lumens/watt.

consumption is 5watts. Used for night lamps, indicator lamps,

decoration and advertising.

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Fluorescent lamps:

The inside of tube is coated with afluorescent material (zinc berylliumsilicate, calcium tungstate, calcium

borate.)

The efficiency of the lamp is about40 lumens/wattand life is 4000

hours.

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Lamps for differentsituations:

s.No Lighting scheme Lamps used

1. Domestic Fluorescent,incandescent, CLFlamps

2. Industrial M.V.lamps,fluorescent

3. Decoration M.V, S.V ,

neon,halogen lamps

4. Advertising M.V, neon, halogenlamps

5. Street M.V, S.V , fluorescent

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