automatic headlight2, rajib

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AUTOMATIC HEAD LIGHTAUTOMATIC HEAD LIGHT

PRESENTED BY :

RAJIB KUMAR PANDA

ROLL NO. 25226REG NO. 0601105091

19-Feb-11 EE/IGIT

GUIDED BY:

MRS. A .ROUT

Electrical Engineering Department

Indira Gandhi Institute of Technology

Sarang-759146, Dhenkanal, Orissa

1



OUTLINESOUTLINES

INTRODUCTION

LIGHT SOURCE

CONSTRUCTION

TWO FILAMENT BULBS

HEAD LIGHT DAZZLES

AUTOMATIC DIPPER

WORKING OF AUTOMATIC DIPPERCONCLUSION

19-Feb-11 EE/IGIT 2



INTRODUCTIONINTRODUCTION

The number of vehicles on our roads is increasing dayby day. An automatic dipper is a unit, which canautomatically judge when the headlight beam needs to

be lowered, and which dip the headlamp from whichbeam to a dipped beam.

As the dipper unit is well connected to the lightingsystem of the vehicle, we have to look into the typeand construction of a head light before discussing the

wiring diagram or the construction of Automaticdippers.

19-Feb-11 EE/IGIT 3



LIGHT SOURCELIGHT SOURCE

There are two kinds of light sources

One that emits light.

Other that reflects lights.

The headlight is composed of three elements:

The light filament that gives off light when a currentflows through it.

The parabolic reflector that reflect the light infront.

The lens that refracts of distorts the light beaminto an illuminating pattern.

19-Feb-11 EE/IGIT 4



CONSTRUCTIONCONSTRUCTION

Earlier the bulb was placed at the focus of a

parabolic silvered reflector in order to give a

parallel beam of light.

The following figure shows a parabolicreflector with bulb, the lines showing light rays

emitted from the filament of the bulb in all

directions.

This type of headlight given a parallel lightbeam.

19-Feb-11 EE/IGIT 5



The parabolic reflector showing light

rays emitted from the filament of the bulb

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The effect of changing the position of

filament on the nature of the light beam

19-Feb-11 EE/IGIT 7



TWO FILAMENT BULBSTWO FILAMENT BULBS

In two filaments headlights there uses atwo-filament bulb with a fixed reflector.In this case, one filament is meant for the

dipping beam and the other main beam The main beam filament is located at the

focus of the reflector.

The dip beam filament is located behindthe focus.

19-Feb-11 8



A double ± filament lamp

19-Feb-11 EE/IGIT 9



HEADLIGHT DAZZLESHEADLIGHT DAZZLES

The dazzle effect is one of the major problems

faced by a driver in night driving

Automatic Dipper is one such mechanism,

which is employed for safety night drivingwithout the intense dazzling effects

The dazzling effect can be prevented by

Reducing the brightness of the headlights of the

vehicles.

Stopping high intensity light from entering the

vehicles of on-coming drivers or road users.

19-Feb-11 EE/IGIT 10



MAIN COMPONENTSMAIN COMPONENTS

Light sensitive photocell

High-low beam relay

Sensitivity control

Amplifier.




WORKINGWORKING

The photoelectric cell senses the intensity of light fromthe oncoming vehicles.

The sensitivity control sets the intensity level at which

the photocell amplifier will energize.

When the light from the oncoming strikes the lightsensitive plate provided in it, an electric current is

released.

When the oncoming vehicle is nearing, its strong light

sets the amplifier unit(thyraton) into operation. The thyraton greatly amplifies the current provided by

the phototube.

It becomes strong enough to put the power relay unit

into operation.19-Feb-11 EE/IGIT 13



SINGLE POLE DOUBLESINGLE POLE DOUBLE

THROW RELAYTHROW RELAYy Current will flow between the movable contact and

one fixed contact when the coil is DEenergized and

between the movable contact and the alternate fixed

contact when the relay coil is energized.




WORKING OF AUTO DIPPERWORKING OF AUTO DIPPER




CONCLUSIONCONCLUSION

Auto dippers are devices, which will attain

more and more importance in the

forthcoming years.

When we are driving on busy street, it is

a great problem to change the light from

head to dipper or vise versa.

So, this mechanism can give the solutionfor the above problems.




THANK YOU


automatic headlight2, rajib

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