tesis rekacipta

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MARA JUNIOR SCIENCE COLLEGE MERSING NUR FATIN BINTI MOHD HANIFF SITI SAIDATUL SYAFIKA BINTI MOHD ZAHIR AMIRAH BINTI NASIR THIS THESIS HAD BEEN DONE TO FULFILL THE GRADUATION CONDITION OF MARA JUNIOR SCIENCE COLLEGE INVENTION CATEGORY

description

contoh tesis tuntuk sem

Transcript of tesis rekacipta

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MARA JUNIOR SCIENCE COLLEGE MERSING

 

 

 

 

 

NUR FATIN BINTI MOHD HANIFF

 

SITI SAIDATUL SYAFIKA BINTI MOHD ZAHIR

 

AMIRAH BINTI NASIR

 

 

 

 

 

THIS THESIS HAD BEEN DONE TO FULFILL

 

THE GRADUATION CONDITION OF

 

MARA JUNIOR SCIENCE COLLEGE

 

 

 

 

INVENTION CATEGORY

 

 

 

MARA JUNIOR SCIENCE COLLEGE

MERSING

 

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PROJECT ADVISOR’S CONFIRMATION

 

 

 

 

This thesis is prepared by:

 

 

 

NUR FATIN BINTI MOHD HANIFF

 

AMIRAH BINTI NASIR

 

SITI SAIDATUL SYAFIKA BINTI MOHD ZAHIR

 

 

 

 

 

..............................                                   .............................

( FATIN )                                     ( AMIRAH )

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..............................

( SYAFIKA )

 

 

 

Accepted as to fulfil part

 

of the graduation requirement of

 

Mara Junior Science College, Mersing

 

 

 

 

                                                                         Project’s Advisor : ……………………..

                                                                         ( PUAN NOOR SALINAWATI )

 

 

 

                                                Date: ………………..

 

 

 

 

 

 

 

 

 

CONFESSION

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We confessed that this masterpiece are

 

By own works accept for some of the

 

Information which the sources had been stated.

 

 

 

Signature :   …………………                                   …………………..

 

 

 

 

…………………

 

 

 

 

 

 

Members :                   NUR FATIN BINTI MOHD HANIFF

 

AMIRAH BINTI NASIR

 

SITI SAIDATUL SYAFIKA BINTI MOHD ZAHIR

 

 

 

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Date :      11th June 2007

 

 

 

 

 

 

 

 

 

 

 

 

DEDICATION

 

 

 

 

 

 

 

For our beloved parents and families

 

That had sacrificed a lot of energy and money

 

To help us finish our project.

 

To our helpful friends,

 

not forgotten also others that we didn’t mention their name.

 

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We would like to thank Mr..Mohd Haniff’s family.

 

To Mr. Nasir’s family,

 

To Mr. Mohd Zahir’s family,

 

Not to be forgotten to our advisor Mrs. Noor Salinawati

 

A lot of thank you for our cooperation

 

And support for us to finish this project succesfully.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

APPRECIATION

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We would like to give this taken appreciation to our project’s supervisor. Mrs. Noor

 

Salinawati regarding her guidance, advise and remarkable opinions while research

 

Was conducted.

 

 

 

We also would like to thanks our family whom made a big sacrification  regarding

 

times, money and energy n order to complete this project. A big thanks to our friend

 

whom helped a lot to make this invention a success.

 

 

 

 

Lastly yet importantly to everyone involved either directly or indirectly.

 

 

 

 

 

 

 

 

 

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ABSTRACT

 

 

 

 

 

 

 

 

This Automatical Lamp was specially designed to simplify the use of car’s light when

 

the condition is necessary to use high and low lights alternately. This is because most

 

of the drivers will have dazzle problems when clashing with other car which use high

 

light.  With this invention of ours, drivers will have not complication instead car drive

 

comfortably.  There’s  a  lot  of  advantage  of this invention, can lead for decreases in

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rate of accidents. Therefore, we highly put our hope in those who will to judge our

 

project on work with full of fairness. Thank you.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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LIST OF CONTENT

 

 

 

 

TITLE                                                                                                                 PAGE         

 

 

 

Supervisor’s authenticate

 

Confession

 

Dedication

 

Appreciation

 

Abstract

 

List of content 

 

 

 

 

 

CHAPTER  1

 

 

1.0  Introduction

 

               1.1 Definision                                                                                                   1

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               1.2 Idea of invention                                                                                        1

 

                                                                                                        

 

 

 

 

 

 

 

 

 

 

 

 

  CHAPTER   2

 

 

2.0  Objective

 

               2.1 To fulfill the graduation’s need                                                                   2

 

               2.2 Applying the concept of physics, science and technology                     2

 

               2.3 Usage of creative ideas                                                                           3

 

 

 

 

 

 

 CHAPTER  3

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3.0   Procedure

 

 

               3.1 Problem statement                                                                                   4

 

               3.2 Drawing the project plan                                                                        5

 

               3.3 Make the  prototype                                                                               5

 

               3. 4 Improve the prototype                                                                           5

 

               3.5 Benifits                                                                                                   6

 

               3.6 Strategy of promoting the products                                                       7

 

               3.8 Product’s cost                                                                                          8

                       

 

 

 

 

 

 CHAPTER  4

 

 

               4.1 Inquiry form                                                                                        9

 

               4.2 The percentage of the respondent                                                      10

 

               4.3 Graph                                                                                                 11

 

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 CHAPTER  5

 

 

               5.1 Conclusion                                                                                          12

 

 

 

  CHAPTER     6

 

 

               6.1 Duties division                                                                                 13-14

 

               6.2 Writer’s Profile                                                                                15- 16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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CHAPTER 1 

INTRODUCTION 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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1.0  INTRODUCTION

 

 

 

.1.1 DEFINITION

 

 

 

 Automatical Lamp

 

 Automatical means a gadget  which  functioning by itself  without frequent  control.

 

This lamp give imagination  to  our car  model  that  will change  from  high lamp to

 

lower   lamp  when   light  emitted   diod  is  show to  light.  Automatical  Lamp  is 

 

prototype  which use electric that  can allow the light emitted  diod  to function.

 

 

 

 

 

 

 1.2 INVENTORY IDEA

 

 The  idea  was  at  first  came  when one of our group member told us her father’s

 

complaint  when  driving  during  night time.  This  happen  when driver’s  from

 

opposite  direction  frequently did not change the lights from high to  low when 

 

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passing  causing  dazzle to opposite drivers. This situation will naturally lead into

 

unwanted accidents. After lot of discussion, we had made our decision to create an

 

automatic lamp to benefits today’s drivers.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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 CHAPTER 2

 OBJECTIVES

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2.0 Objective

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2.1 As to fulfill MJSC Mersing graduation’s need

 

 

 

Each   students of MJSC Mersing   must  followed  and  done the School And

 

Enrichment Module (S.E.M)  and Type 3  and also work out the investigation with the

 

scoop that have been  given by   the college. Every   student   and  succeed  and pass

 

this program will be given the certificate  .

 

 

 

 

 

 

 

 

 

2.2 Apllication of Physics, Science and Technology concepts.

 

 

 

In  order  to complete  this  invention  we had  used  physics concept  and combined 

 

with Science  and Technology  nowadays. The  usage of light – sensitive – receptor

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connected vehicle’s lamp  wire and   able   high light switched to low light

 

automatically describes the technology that we are trying to convey.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2.3              Usage of creative ideas to develop something

 

 

 

 

 

This   design   had  taught   us   to   be   more confident in making the new product . 

 

This experiences can also be used for the future ,especially  when we are in the

 

university one day . Our country need their  people to be creative and can compete

 

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each other .

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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CHAPTER 3 

PROCEDURE 

 

 

 

 

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3.0 : PROCEDURE

 

 

3.1 Problem statement

 

We had found a  problem of the drivers  especially when it  comes night. When  two cars 

 

reach nearer to each other from  different ways at night , especially on  the road   without

 

any  source of light, the light from both  cars will  cause the  both of  the  drivers difficult

 

to  see  clearly. This will  makes it dangerous to  a  drivers to drive at   night. One of   the 

 

drivers   had  to  lowered  his  car’s light  quickly  and   had to open  the  highlight  again.

 

But if the number of cars are big , this  will cause difficulties to the drivers. This also can

 

 cause accident to happen.

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3.2   Drawing The Project’s Plan

 

 

The drawing started when we get the imagination from a light sensitive receptor that

 

Will connect  to   the vehicle’s lamp. We   choose   light sensitive   receptor as the

 

main thing because this receptor is very sensitive to the light.

 

 

 

 

 

 

3.3              Make The Prototype

 

The prototype is build after we had drew the plan’s drawing. We need to set up the

 

things that needed. This prototype needs to be connected to the wire of the vehicles.

 

Other than that,  the prototype must have a box that contains other component.

 

 

 

 

 

3.4              Improve The Prototype

 

After that is the process of   improvement   of the prototype. This   process is to make

 

the prototype looks more neat and attractive. After that, we need to make final check

 

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to the prototype ,that is improve the outside components of the prototype by covering

 

the box that contain the circuit by using  black paper.

 

 

 

 

 

 

 

 

 

 

 

 

 

BENEFITS

 

 

 

 

 

1.                  It can be used to all of the transport .

 

 

2.                  Cos of making this project is cheap and affordable .

 

 

3.                  Decrease the statistic of accident on the road at night.

 

 

4.                  Make an easier to driver especially who is always drive at night .

 

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5.                  Drivers can be more focus on driving.

 

 

 

 

 

 

 

 

 

 

 

 

                                                                                   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Strategy Of Promoting The Product

 

 

 

 

 

                    Introduce the product to the university such as University Technology of

            Malaysia  to add the quality of the product.

 

 

                    Introduce the product to the automotive factory such as Proton Edar .

 

 

                    Promote to the internet , news paper and the television.

 

 

                    Make an open carnival at the National Science Centre.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Cost for making this project

 

 

NO. COMPONENT QUANTITY COST TOTAL

1 Adaptor 1 RM10.00 RM10.00

2 Light sensor 1 RM12.00 RM12.00

3 L.E.D 4 RM0.50 RM2.00

4 Glue (UHU) 1 RM1.80 RM1.80

5 Cellophane tape 1 RM1.00 RM1.00

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6 Transistor 3 RM8.00 RM24.00

7 Switch 2 RM4.00 RM8.00

8 Wire _ RM3.00 RM3.00

9 Relay 1 RM6.00 RM6.00

                                                                                       TOTAL Rm67.80

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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CHAPTER 4 

CONCLUSION 

 

 

 

 

 

 

 

 

 

 

 

 

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.

 

 

 

Inquiry Form

 

Name:

Age:

Occupation:

 

Do you think that this ‘Automatical magic lamp’ is important for today life?

Yes                                                     No

 

Will you use this ‘Automatically magic lamp’ to your transportation?

Yes                                                     No

 

Comments:

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___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

__________________________________________________

 

 

 

 

 

 

 

 

 

 

 

 

 

4.2 The percentage of the respondent results

 

 

 

Based on the form that we had done, it is shows that more respondent were attracted

 

and agreed to choose and use this automatical lamp  as if it will be put in their

 

vehicles. However, there were less respondent do not attracted to this project. Many

 

comment that we received shows that this project has many benefit for our future life.

 

other than that it is also can reduce the risk of an accidents.

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GRAPH OF NUMBER OF RESPONDENT THAT AGREE OR DISAGREE WITH AUTOMATICAL LAMP

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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CHAPTER 5 

CONCLUSION 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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            Conclusion

 

As the conclusion  , we hope that our invention which is Automatically Magic Lamp

will give a lot of benefit to the society for the future when it has been commercial . We are

also been  proud if our invention get a support from the society around this country. Other

than that, we are also want to thanks to everybody who gives us a lot of support for helping

us in the process for finishing this project especially to our advisors, Mdm. Noor Salinawati   

who had gives us many advice in doing this invention

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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CHAPTER 6

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 ENCLOSURE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Duties division

 

 

 

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Fatin

- Act as the leader

- involve in making the prototype.

- typing the thesis

-give the creative ideas

 

Syafika

-involve in making the prototype.

- typing the thesis

-give the creative ideas

 

 

 

 

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Amirah

-involve in making the prototype.

- typing the thesis

-give the creative ideas

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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GROUP MEMBERS PROFILE

 

 

 

Name :  Siti Saidatul Syafika Bt. Mohd Zahir

I/C Number : 900511-01-5946

Matrix number : M064075

Address : No.21,Jalan Hulubalang, Taman Bendahara,85000 Segamat Johor Darul

                 Takzim

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Ambition : Architect

 

 

 

 

Name: Amirah bt. Nasir

I/C Number: 900304-01-5388

Matrix number: M064133

Address: No.10, Jalan Perdana 2/11 A, Taman Bukit Perdana, 83000 Batu Pahat,

                Johor Darul takzim.  

Ambition: Doctor

 

 

 

 

 

 

 

 

 

Name: Nur Fatin Bt. Mohd Haniff

I/C Number: 901206-01-5282

Matrix number: M064012

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Address: 697, Quarters Kajicuaca, Jalan Endau, 86800 Mersing, Johor Darul

                Takzim.       

Ambition: Cardiologist

 

 

 

 

 

 

 

 

 

 

Name: Nurul Syahidah Bt. Mohamad Radzali

I/C Number: 901010-11-5038

Matrix number: M064117

Address: A55045 Ladang Paya Lang, Batu Anam, 85100 Segamat, Johor

               Darul Takzim

Ambition: Electrical Engineering

 

 

 

 

 

 

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RelayFrom Wikipedia, the free encyclopedia

Jump to: navigation, searchThis article is about the electronic component. For other uses, see Relay (disambiguation).Automotive style miniature relayA relay is an electrical switch that opens and closes under the control of another electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. It was invented by Joseph Henry in 1835. Because a relay is able to control an output circuit of higher power than the input circuit, it can be considered, in a broad sense, to be a form of an electrical amplifier.

Contents

[hide] 1 Operation 2 Types of relay

o 2.1 Latching relay o 2.2 Reed relay

2.2.1 Mercury-wetted relay

o 2.3 Polarized relay o 2.4 Machine tool relay o 2.5 Contactor relay o 2.6 Solid state contactor relay o 2.7 Buchholz relay o 2.8 Forced-guided contacts

relay o 2.9 Solid-state relay o 2.10 Overload protection relay

3 Pole & Throw 4 Applications 5 Relay application considerations 6 Protective relay 7 Overcurrent relay

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8 See also 9 References 10 External links

 

[edit] Operation

When a current flows through the coil, the resulting magnetic field attracts an armature that is mechanically linked to a moving contact. The movement either makes or breaks a connection with a fixed contact. When the current to the coil is switched off, the armature is returned by a force approximately half as strong as the magnetic force to its relaxed position. Usually this is a spring, but gravity is also used commonly in industrial motor starters. Most relays are manufactured to operate quickly. In a low voltage application, this is to reduce noise. In a high voltage or high current application, this is to reduce arcing.If the coil is energized with DC, a diode is frequently installed across the coil, to dissipate the energy from the collapsing magnetic field at deactivation, which would otherwise generate a spike of voltage and might cause damage to circuit components. If the coil is designed to be energized with AC, a small copper ring can be crimped to the end of the solenoid. This "shading ring" creates a small out-of-phase current, which increases the minimum pull on the armature during the AC cycle.[1]

By analogy with the functions of the original electromagnetic device, a solid-state relay is made with a thyristor or other solid-state switching device. To achieve electrical isolation, a light-emitting diode (LED) is used with a photo transistor.

[edit] Types of relay

Small relay as used in electronics

[edit] Latching relay

A latching relay has two relaxed states (bistable). These are also called 'keep' relays. When the current is switched off, the relay remains in its last state. This is achieved with a solenoid operating a ratchet and cam mechanism, or by having two opposing coils with an over-center spring or permanent magnet to hold the armature and contacts in position while the coil is relaxed, or with a remnant core. In the ratchet and cam example, the first pulse to the coil turns the relay on and the second pulse turns it off. In the two coil example, a pulse to one coil turns the relay on and a pulse to the opposite coil turns the relay off. This type of relay has the advantage that it consumes power only for an instant, while it is being switched, and it retains its last setting across a power outage.

[edit] Reed relay

A reed relay has a set of contacts inside a vacuum or inert gas filled glass tube, which protects the contacts against atmospheric corrosion. The contacts are closed by a magnetic field generated when current passes through a coil around the glass tube. Reed relays are capable of faster switching speeds than conventional relays. See also reed switch.

[edit] Mercury-wetted relay

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A mercury-wetted reed relay is a form of reed relay in which the contacts are wetted with mercury. Such relays are used to switch low-voltage signals (one volt or less) because of its low contact resistance, or for high-speed counting and timing applications where the mercury eliminates contact bounce. Mercury wetted relays are position-sensitive and must be mounted vertically to work properly. Because of the toxicity and expense of liquid mercury, these relays are rarely specified for new equipment. See also mercury switch.

[edit] Polarized relay

A Polarized Relay placed the armature between the poles of a permanent magnet to increase sensitivity. Polarized relays were used in middle 20th Century telephone exchanges to detect faint pulses and correct telegraphic distortion. The poles were on screws, so a technician could first adjust them for maximum sensitivity and then apply a bias spring to set the critical current that would operate the relay.

[edit] Machine tool relay

A machine tool relay is a type standardized for industrial control of machine tools, transfer machines, and other sequential control. They are characterized by a large number of contacts (sometimes extendable in the field) which are easily converted from normally-open to normally-closed status, easily replaceable coils, and a form factor that allows compactly installing many relays in a control panel. Although such relays once were the backbone of automation in such industries as automobile assembly, the programmable logic controller mostly displaced the machine tool relay from sequential control applications.

[edit] Contactor relay

A contactor is a very heavy-duty relay used for switching electric motors and lighting loads. With high current, the contacts are made with pure silver. The unavoidable arcing causes the contacts to oxidize and silver oxide is still a good conductor. Such devices are often used for motor starters. A motor starter is a contactor with overload protection devices attached. The overload sensing devices are a form of heat operated relay where a coil heats a bi-metal strip, or where a solder pot melts, releasing a spring to operate auxiliary contacts. These auxiliary contacts are in series with the coil. If the overload senses excess current in the load, the coil is de-energized. Contactor relays can be extremely loud to operate, making them unfit for use where noise is a chief concern.

[edit] Solid state contactor relay

25 amp or 40 amp solid state contactorsA solid state contactor is a very heavy-duty solid state relay, including the necessary heat sink, used for switching electric heaters, small electric motors and lighting loads; where frequent on/off cycles are required. There are no moving parts to wear out and there is no contact bounce due to vibration. They are activated by AC control signals or DC control signals from Programmable logic controller (PLCs), PCs, Transistor-transistor logic (TTL) sources, or other microprocessor controls.

[edit] Buchholz relay

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A Buchholz relay is a safety device sensing the accumulation of gas in large oil-filled transformers, which will alarm on slow accumulation of gas or shut down the transformer if gas is produced rapidly in the transformer oil.

[edit] Forced-guided contacts relay

A forced-guided contacts relay has relay contacts that are mechanically linked together, so that when the relay coil is energized or de-energized, all of the linked contacts move together. If one set of contacts in the relay becomes immobilized, no other contact of the same relay will be able to move. The function of forced-guided contacts is to enable the safety circuit to check the status of the relay. Forced-guided contacts are also known as "positive-guided contacts", "captive contacts", "locked contacts", or "safety relays".A solid state relay, which has no moving parts

[edit] Solid-state relay

A solid state relay (SSR) is a solid state electronic component that provides a similar function to an electromechanical relay but does not have any moving components, increasing long-term reliability. With early SSR's, the tradeoff came from the fact that every transistor has a small voltage drop across it. This collective voltage drop limited the amount of current a given SSR could handle. As transistors improved, higher current SSR's, able to handle 100 to 1,200 amps, have become commercially available. Compared to electromagnetic relays, they may be falsely triggered by transients.

[edit] Overload protection relay

One type of electric motor overload protection relay is operated by a heating element in series with the electric motor . The heat generated by the motor current operates a bi-metal strip or melts solder, releasing a spring to operate contacts. Where the overload relay is exposed to the same environment as the motor, a useful though crude compensation for motor ambient temperature is provided.

[edit] Pole & Throw

Circuit symbols of relays. "C" denotes the common terminal in SPDT and DPDT types.Since relays are switches, the terminology applied to switches is also applied to relays. A relay will switch one or more poles, each of whose contacts can be thrown by energizing the coil in one of three ways:

Normally-open (NO) contacts connect the circuit when the relay is activated; the circuit is disconnected when the relay is inactive. It is also called a Form A contact or "make" contact.

Normally-closed (NC) contacts disconnect the circuit when the relay is activated; the circuit is connected when the relay is inactive. It is also called a Form B contact or "break" contact.

Change-over, or double-throw, contacts control two circuits: one normally-open contact and one normally-closed contact with a common terminal. It is also called a Form C contact or "transfer" contact.

The following types of relays are commonly encountered:

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SPST - Single Pole Single Throw. These have two terminals which can be connected or disconnected. Including two for the coil, such a relay has four terminals in total. It is ambiguous whether the pole is normally open or normally closed. The terminology "SPNO" and "SPNC" is sometimes used to resolve the ambiguity.

SPDT - Single Pole Double Throw. A common terminal connects to either of two others. Including two for the coil, such a relay has five terminals in total.

DPST - Double Pole Single Throw. These have two pairs of terminals. Equivalent to two SPST switches or relays actuated by a single coil. Including two for the coil, such a relay has six terminals in total. It is ambiguous whether the poles are normally open, normally closed, or one of each.

The diagram on the package of a DPDT AC coil relay DPDT - Double Pole Double Throw. These have two rows of change-over terminals.

Equivalent to two SPDT switches or relays actuated by a single coil. Such a relay has eight terminals, including the coil.

QPDT - Quadruple Pole Double Throw. Often referred to as Quad Pole Double Throw, or 4PDT. These have four rows of change-over terminals. Equivalent to four SPDT switches or relays actuated by a single coil, or two DPDT relays. In total, fourteen terminals including the coil.

[edit] Applications

A DPDT AC coil relay with "ice cube" packagingRelays are used:

to control a high-voltage circuit with a low-voltage signal, as in some types of modems,

to control a high-current circuit with a low-current signal, as in the starter solenoid of an automobile,

to detect and isolate faults on transmission and distribution lines by opening and closing circuit breakers (protection relays),

to isolate the controlling circuit from the controlled circuit when the two are at different potentials, for example when controlling a mains-powered device from a low-voltage switch. The latter is often applied to control office lighting as the low voltage wires are easily installed in partitions, which may be often moved as needs change. They may also be controlled by room occupancy detectors in an effort to conserve energy,

to perform logic functions. For example, the boolean AND function is realised by connecting NO relay contacts in series, the OR function by connecting NO contacts in parallel. The change-over or Form C contacts perform the XOR (exclusive or) function. Similar functions for NAND and NOR are accomplished using NC contacts. The Ladder programming language is often used for designing relay logic networks.

o Early computing. Before vacuum tubes and transistors, relays were used as logical elements in digital computers. See ARRA relay computer, Harvard Mark II relay computer, Zuse Z2 relay computer, Zuse Z3 relay computer.

o Safety-critical logic. Because relays are much more resistant than semiconductors to nuclear radiation, they are widely used in safety-critical logic, such as the control panels of radioactive waste-handling machinery.

to perform time delay functions. Relays can be modified to delay opening or delay closing a set of contacts. A very short (a fraction of a second) delay would use a

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copper disk between the armature and moving blade assembly. Current flowing in the disk maintains magnetic field for a short time, lengthening release time. For a slightly longer (up to a minute) delay, a dashpot is used. A dashpot is a piston filled with fluid that is allowed to escape slowly. The time period can be varied by increasing or decreasing the flow rate. For longer time periods, a mechanical clockwork timer is installed.

[edit] Relay application considerations

A large relay with two coils and many sets of contacts, used in an old telephone switching system.Selection of an appropriate relay for a particular application requires evaluation of many different factors:

Number and type of contacts - normally open, normally closed, changeover (double-throw)

In the case of changeover, there are two types. This style of relay can be manufactured two different ways. "Make before Break" and "Break before Make". The old style telephone switch required Make-before-break so that the connection didn't get dropped while dialing the number. The railroad still uses them to control railroad crossings.

Rating of contacts - small relays switch a few amperes, large contactors are rated for up to 3000 amperes, alternating or direct current

Voltage rating of contacts - typical control relays rated 300 VAC or 600 VAC, automotive types to 50 VDC, special high-voltage relays to about 15,000 V

Coil voltage - machine-tool relays usually 24 VAC or 120 VAC, relays for switchgear may have 125 V or 250 VDC coils, "sensitive" relays operate on a few milliamperes

Package/enclosure - open, touch-safe, double-voltage for isolation between circuits, explosion proof, outdoor, oil-splashresistant

Mounting - sockets, plug board, rail mount, panel mount, through-panel mount, enclosure for mounting on walls or equipment

Switching time - where high speed is required "Dry" contacts - when switching very low level signals, special contact materials may

be needed such as gold-plated contacts Contact protection - suppress arcing in very inductive circuits Coil protection - suppress the surge voltage produced when switching the coil current Isolation between coil circuit and contacts Aerospace or radiation-resistant testing, special quality assurance Expected mechanical loads due to acceleration - some relays used in aerospace

applications are designed to function in shock loads of 50 g or more Accessories such as timers, auxiliary contacts, pilot lamps, test buttons Regulatory approvals Stray magnetic linkage between coils of adjacent relays on a printed circuit board.

[edit] Protective relay

A protective relay is a complex electromechanical apparatus, often with more than one coil, designed to calculate operating conditions on an electrical circuit and trip circuit breakers when a fault was found. Unlike switching type relays with fixed and usually ill-defined operating voltage thresholds and operating times, protective relays had well-established,

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selectable, time/current (or other operating parameter) curves. Such relays were very elaborate, using arrays of induction disks, shaded-pole magnets, operating and restraint coils, solenoid-type operators, telephone-relay style contacts, and phase-shifting networks to allow the relay to respond to such conditions as over-current, over-voltage, reverse power flow, over- and under- frequency, and even distance relays that would trip for faults up to a certain distance away from a substation but not beyond that point. An important transmission line or generator unit would have had cubicles dedicated to protection, with a score of individual electromechanical devices. Each of the protective functions available on a given relay are denoted by standard ANSI Device Numbers. For example, a relay including function 51 would be a timed overcurrent protective relay.Design and theory of these protective devices is an important part of the education of an electrical engineer who specializes in power systems. Today these devices are nearly entirely replaced (in new designs) with microprocessor-based instruments (numerical relays) that emulate their electromechanical ancestors with great precision and convenience in application. By combining several functions in one case, numerical relays also save capital cost and maintenance cost over electromechanical relays. However, due to their very long life span, tens of thousands of these "silent sentinels" are still protecting transmission lines and electrical apparatus all over the world.Top, middle: reed switches, bottom: reed relay

[edit] Overcurrent relay

An "Overcurrent Relay" is a type of protective relay. The ANSI Device Designation Number is 50 for an Instantaneous OverCurrent (IOC), 51 for a Time OverCurrent (TOC). In a typical application the overcurrent relay is used for overcurrent protection, connected to a current transformer and calibrated to operate at or above a specific current level. When the relay operates, one or more contacts will operate and energize a trip coil in a Circuit Breaker and trip (open) the Circuit Breaker.

[edit] See also

Contactor Dry contact Wire spring relay

[edit] References

1. Vladimir Gurevich "Electrical Relays: Principles and Applications", CRC Press (Taylor & Francis group), London - New York, 2005, 704 pp. 2. Westinghouse Corporation, Applied Protective Relaying, 1976, Westinghouse Corporation, no ISBN, Library of Congress card no. 76-8060 - a standard reference on electromechanical protection relays (out of print - current edition published by ABB)3. Terrell Croft and Wilford Summers (ed), American Electricians' Handbook, Eleventh Edition, McGraw Hill, New York (1987) ISBN 0-07-013932-6

1. ̂ Mason, C. R., Art & Science of Protective Relaying, Chapter 2, GE Consumer & Electrical [1],

[edit] External links

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Information about relays and the Latching Relay circuit Example of the circuitry within a solid state relay Solid state relay -- heat sink and thermal considerations Relay Cross Reference Protective relay technical resource library from Manta Test Systems "Harry Porter's Relay Computer", a computer made out of relays.

Retrieved from "http://en.wikipedia.org/wiki/Relay" 

                                          

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                              4.2 The percentage of the respondent results  

 

 

 

Based on the form that we had done, it is shows that more respondent were attracted and

agreed to choose and use this automatical magic lamp as if it will be put in their vehicles.

However, there were less respondent do not attracted to this project. Many comment that we

received shows that this project has many benefit for our future life. Other than that it is also

can reduce the risk of an accident.

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