A Project Report on

“ADVANCED SPEED BREAKER”

Submitted in partial fulfilment of the requirement for Award of the Degree

Bachelors of Technology

In

Mechanical Engineering

Under The Guidance of

Er. ANS KHAN

(Assistant Prof.)

Submitted By

Asad Ahmad (1232140013)

Deepak Jindal (1232140020)

Ishant Gautam (1232140025)

Jawed Akhtar (1232140028)

Kafeel Ahmad (1232140030)

Department Of Mechanical Engineering

TRANSLAM INSTITUTE OF TECHNOLOGY & MANAGEMENT

(Dr. A.P.J Abdul Kalam Technical University, Lucknow)

(Batch: 2012-2016)

i

A Project Report on

“ADVANCED SPEED BREAKER”

Submitted in partial fulfilment of the requirement for Award of the Degree

Bachelors of Technology

In

Mechanical Engineering

Submitted By:

Under The Guidance of

Er. Anas Khan

(Assistant Prof.)

Asad Ahmad (1232140013)

Deepak Jindal (1232140020)

Ishant Gautam (1232140025)

Jawed Akhtar (1232140028)

Kafeel Ahmad (1232140030)

Department Of Mechanical Engineering

TRANSLAM INSTITUTE OF TECHNOLOGY & MANAGEMENT

(Dr. A.P.J Abdul Kalam Technical University, Lucknow)

(Batch: 2012-2016)

ii

DECLARATION

We hereby declare that the work, which is being presented in the project report,

entitled “Advanced Speed Breaker”. In the partial fulfillment for the award of

degree of “Bachelors of Technology” in department of Mechanical Engineering

and submitted to the Mechanical Engineering Department, Translam Institute of

Technology & Management affiliated to Dr. A.P.J Abdul Kalam Technical

University, Lucknow (U.P) is a record of our to own investigations carried under

the guidance of Er. Anas Khan, Assistant professor.

The matter of presented in the project has been submitted in any other

University/Institute for the award of Bachelors degree.

Signature: Signature:

Name: Asad Ahmad Name: Deepak Jindal

(Roll No.: 1232140013) (Roll No.: 1232140020)

Signature: Signature:

Ishant Gautam Jawed Akhtar

(Roll No.: 1232140025) (Roll No.: 1232140028)

Signature:

Kafeel Ahmad

(Roll No.: 1232140030)

iii

CERTIFICATE

This is to certify that Asad Ahmad (1232140013), Deepak Jindal (1232140020),

Ishant Gautam (1232140025), Jawed Akhtar (1232140028), Kafeel Ahmad

(1232140030) have carried out a project and study work on “Advanced Speed

Breaker” for the partial fulfillment of the award of the degree of Bachelors of

Technology in Mechanical Engineering in Translam Institute of Technology &

Management (Affiliated to Dr. A.P.J Abdul Kalam Technical University,

Lucknow) during the academic year 2012-2016.

Prof. Vikas Singh Er. Anas Khan

(H.O.D) (Project Guidance)

iv

ACKNOWLEDGEMENT

It gives us a great sense of pleasure to present the report of Advanced Speed

Breaker undertaken during B. Tech. Final Year. We owe special debt of gratitude

to Professor Anas Khan, Department of Mechanical Engineering, Translam

Institute Of Technology And Management, Meerut for his constant support and

guidance throughout the course of our work. His sincerity, thoroughness and

perseverance have been a constant source of inspiration for us. It is only his

cognizant efforts that our endeavors have seen light of the day.

We also take the opportunity to acknowledge the contribution of Professor Vikas

Singh, Head, Department of Mechanical Engineering, Translam Institute of

Technology And Management, Meerut for his full support and assistance during

the development of the project.

We also do not like to miss the opportunity to acknowledge the contribution of all

faculty members of the department for their kind assistance and cooperation

during the development of our project. Last but not the least, we acknowledge our

friends for their contribution in the completion of the project.

Asad Ahmad

Deepak Jindal

Ishant Gautam

Jawed Akhtar

Kafeel Ahmad

v

LIST OF FIGURES

Sl. No.

TITLE OF FIGURE

PAGE NO.

1.1

Wood structure 2

1.2

Screw jack 2

1.3

Relay 2

1.4

Buzzer 2

1.5

LEDs 2

1.6

Working of screw jack 4

1.7

Circuit diagram of relay 6

1.8

Actual diagram of relay 6

1.9

Stepper motor 8

1.10

Inside view of dc motor 8

2.1

Block diagram of microcontroller 9

2.2

Circuit diagram of capture mode 11

2.3

Circuit diagram of up and down counter 12

2.4

Circuit diagram of Baud Rate Generator 14

2.5

Circuit representation of Programmable Clock Out

16

3.1

Output characteristics of power down mode

16

3.2

AC characteristics 17

4.1

The ideal transformer as a circuit element

18

4.2

A step-down transformer 19

5.1

Schematic diagram of a bridge rectifier 20

vi

5.2

Output characteristics of rectifier 21

5.3

Bridge rectifier with smoothen output 22

5.4

Block diagram of voltage regulator 23

5.5

Internal block diagram of voltage regulator 24

6.1

Line diagram of fixed resistor 26

6.2

Colour coding of resistor 27

7.1

Circuit diagram of n-p-n & p-n-p transistor

29

7.2

Composition of transistor 29

7.3

Representation of emitter, base & collector in transistor

30

7.4

Heat sink 30

8.1

Representation of diode 33

8.2

Power diode & Signal diode 33

8.3

Line diagram of semiconductor diode

35

8.4

Line diagram of Zener diode

36

8.5

VI characteristics of Zener diode 36

9.1

Various types of Capacitor 37

9.2 Working of parallel plate capacitor

38

9.3

A simple demonstration of a parallel-plate capacitor 38

9.4

Circuit arrangement of capacitor and resistor 40

vii

LIST OF SYMBOLS

Fload force on the jack exerts by the load

Fin rotational force exerted on the handle of the jack

r length of the jack handle, from the screw axis to where the force is applied

l lead of the screw

V volt

mA milli ampere

MHz mega hertz

pF Pico farad

µF micro farad

IP Current in primary winding

IS Current in secondary winding

VP Induced emf in primary winding

VS Induced emf in secondary winding

NS Number of turns in secondary winding

NP Number of turns in primary winding

τ typical time constant

R resistance

C Capacitance

A ampere

Ohm

W watt

Q Charge

E Electric field

D Plate separation

VC Charging voltage across the capacitor

IE Emitter current

IB Base current

IC Collector current

viii

LIST OF ABBREVIATIONS

COM Common

NC Normally Closed

NO Normally Open

BLDC Brushless DC electric motor

MMF Magneto motive force

EMF Electromotive force

AM Amplitude modulation

FM Frequency modulation

GVW Gross Vehicle Weight

SFR Special Function Register

I/O Input/output

RAM Random Access Memory

VHF Very High Frequency

UHF Ultra High Frequency

WRT with respect to

DCEN Down Counter Enable

ix

TABLE OF CONTENTS

PAGE

DECLARATION ……………………………………………………………………………….i

CERTIFICATE ...……………………………….……………………………...….....................ii

ACKNOWLEDGEMENT ……………………………………………………………….…….iii

LIST OF FIGURES ………………………………………………………………………….....iv

LIST OF SYMBOLS …………………………………………………………..……….………v

LIST OF ABBREVIATIONS ………………………………………………………….....…....vi

CHAPTER 1 INTRODUCTION …………………………………………………………….1-8

1.1 Aim of project ………………………………………………………...………....1

1.2 Hardware requirements ………………………………………………………....2

1.3 Block diagram ……………………………………………………………….......3

1.4 Working of the project ……………………………………………….……….... 4

1.4.1 Screw jack ……………………………………………….…....…4

1.4.1.1 Mechanical advantage ………….…………………..5

1.4.1.2 Limitations ………………………………….…........5

1.4.1.3 Applications ………………………………….……..6

1.5 Relays …………………………………………………………………………....6

1.6 DC motor ………………………………………………………………….……..7

1.6.1 Working of DC motor ……………………………………….….8

CHAPTER 2 MICROCONTROLLER ……………………………………………….……9-15

2.1 Features ……………………………………………………………………………......……..9

2.2 Special function resistors …………………………………………………………...….....…10

2.3 Interrupt resistors ……………………………………………………………........................10

2.3.1 Timer 0 & 1 ……………………………………………………….…...10

2.3.2 Timer 2 ………………………………………………………………...10

2.4 Capture mode ………………………………………………………………….…….….…...11

2.5 Auto-reload (Up or Down Counter) ……………………………………………….........…. 12

2.6 Baud rate generator ………………………………………………………………….………13

2.7 Programmable clock out ……………………………………………………………........… 14

2.8 Idle mode oscillator characteristics ……………………………………..………………......15

x

CHAPTER 3 POWER DOWN MODE …………………………………………………...16-17

3.1.1 AC characteristics ……………………………………………………………17

CHAPTER 4 TRANSFORMER ………………………………………………………… 18-19

4.1 Basic principle …………………………………………………………..........18

4.2 Transformer equation ………………………………………………………...19

CHAPTER 5 RECTIFIER ………………………………………………………………...20-25

5.1 Basic operation …………………………………………………………....… 20

5.2 Output smoothing …………………………………………………………...... 22

5.3 Bridge rectifier with smoothen output ……………………………………...…22

5.4 Voltage regulators …………………………………………………………..…23

5.4.1 Terminal fixed voltage regulator ……………………………..….......23

5.4.2 Internal block diagram …………..………………..…………....……..24

5.4.2.1 Features ……………………..…………..…………..…….….....……24

5.5 Crystal oscillator …………………………………………….………….…..…25

CHAPTER 6 RESISTOR ……………………………………………………………….…26-28

6.1 Types of resistors ………………………………………………………….....…26

6.1.1 Fixed resistors ……………………………………………….…..….26

6.2 Wire wound resistors ………………………………………….……. .27

6.2 Coding of resistors …………………………………..……………………...……27

6.2.1 Resistor colour chart ………………………………………….…......27

6.3 Variable resistors ………………………………………………………….….....28

CHAPTER 7 TRANSISTOR ………………………………………………………..……..29-31

7.1 Emitter ………………………………………………………………………….30

7.2 Base ……………………………………………………………………….……30

7.3 Collector …………………………………………………………….…..……...30

7.4 Heat sink ……………………………………………………………..………...30

7.5 Connectors …………………………………………………………...……..….31

CHAPTER 8 LED (LIGHT EMITTING DIODE) ………………………………...……..32-36

8.1 LED material ……………………………………………………………………32

8.2 Diode ……………………………………………………………………….…...33

xi

8.3 Some common diodes ………………………………………….…………….....34

8.3.1 Zener diode …………………………………………………...……....34

8.3.2 Photo diode ……………………………………………………………34

8.3.3 LED.………………………………………………...…………………34

8.4 Advantages of LED ………………………………………………………………..34

8.5 Semiconductor diode ………………………………………………………………35

8.6 Zener diode …………………………………………………………………...……36

CHAPTER 9 CAPACITOR ……………………………………………………………… 37-41

9.1 Theory of operation ………………………………………………………………38

9.2 Energy storage in capacitor ………………………………………….……….......39

9.3 current-voltage relation …………………………………………………………..39

9.4 DC circuit configuration …………………………………………..……………...40

CHAPTER 10 Specification of Maximum GVW by Govt. of India ……..……………...42-44

CHAPTER 11 CONCLUSION ……………………………………………….................……45

CHAPTER 12 Area of utility and future scope ……………………………………..……....46

References……………………………………………………………………………..………...47

Bibliography ………………………………………………………………………….………...48

xii

A

PROJECT REPORT

ON

ADVANCED SPEED BREAKER

ACTUAL VIEW OF PROJECT

Page 1

CHAPTER-1

INTRODUCTION Energy from Advanced Speed Breaker is a wonderful project for every science student. This is a

very new concept to prevent the accidents and control the speed of vehicles. By using this model

we show the concept, how we can protect the accidents with the help of the speed breaker.

Having an automatic speed breaker on time demand using Embedded Systems tool; it an idea

which is very innovative and useful for the requirements of today’s speedy life.

The concept of the mentioned idea is to give the performance to vehicles as well as to make them

slow. The coding used in the completion of the research work is shown in the thesis. The real

working demo of the research work is very realistic and charming. This can be a very useful in

real life.

1.1 AIM OF PROJECT

In this project we use the automatic speed breaker to control the speed of vehicles at the time of

school and colleges. When the students come at the road, automatically the streets red light ON

for their fix time, then the speed breaker comes out on the road automatically. After the fix time

the breaker automatically gets OFF.

In the fast speed world, there are two perspectives, one is keeping speed and another is to

maintain safety mediums as well. So keeping speed is quite easy for a person and in case of

safety mediums, there must be a lot of attention. For safety purpose, preventing accidents on

road, there is a conventional method of having concrete speed breakers on road.

Page 2

1.2 HARDWARE REQUIREMENTS

1) Wood structure

2) Speed breaker

3) Screw jack

4) Relay

5) Controlling cards

6) BUZZER

7) LEDs

Fig. 1.1 Wood structure Fig. 1.2 Screw jack

Fig. 1.3 Relay Fig. 1.4 Buzzer

Fig. 1.5 LEDs

Page 3

1.3 BLOCK DIAGRAM

CONTROL UNIT

POWER SUPPLY

SENSOR RED

LEDs

SCREW JACK TO

LIFT THE SPEED

BREAKER

SOUND

SYSTEM

Page 4

1.4 WORKING OF THE PROJECT

When speed breaker not required(right to say that when not a single student is on the road) then

there is no speed breaker and all vehicles are going on smoothly (constant speed) on the road. If

there are about to people (students) on the road then firstly sound (bell) will be created and red

light will be glow for dangerous condition. After glowing red lights, speed breaker comes up on

road. So there will be speed breaker on the road that’s why vehicles are going at limited speed.

So we can protect outer areas of schools, colleges, playgrounds etc. by using this project.

1.4.1 SCREW JACK

A jackscrew is a type of jack that is operated by turning a leadscrew. In the form of a screw jack it

is commonly used to lift moderately heavy weights, such as vehicles. More commonly it is used as an

adjustable support for heavy loads, such as the foundations of houses, or large vehicles. These can support a

heavy load, but not lift it.

An advantage of jackscrews over some other types of jack is that they are self-locking, which

means when the rotational force on the screw is removed, it will remain motionless where it was

left and will not rotate backwards, regardless of how much load it is supporting. This makes

them inherently safer than hydraulic jacks, for example, which will move backwards under load

if the force on the hydraulic actuator is accidentally released.

Fig. 1.6 Working of Screw jack

Page 5

1.4.1.1 Mechanical advantage

The mechanical advantage of a screw jack, the ratio of the force the jack exerts on the load to the

input force on the lever, ignoring frictionis

where,

is the force on the jack exerts by the load

is the rotational force exerted on the handle of the jack

is the length of the jack handle, from the screw axis to where the force is applied

is the lead of the screw.

This derives from two factors, the simple lever advantage of a long operating handle and also the

advantage of the inclined plane of the leadscrew. However, most screw jacks have large amounts

of friction which increase the input force necessary, so the actual mechanical advantage is often

only 30% to 50% of this figure.

1.4.1.2 Limitations

Screw jacks are limited in their lifting capacity. Increasing load increases friction within the

screw threads. A fine pitch thread, which would increase the advantage of the screw, also

reduces the size and strength of the threads. Longer operating levers soon reach a point where the

lever will simply bend at their inner end.

Screw jacks have now largely been replaced by hydraulic jacks. This was encouraged in 1858

when jacks by the Tangye company to Bramah's hydraulic press concept were applied to the

successful launching of Brunel's SS Great Britain, after two failed attempts by other means. The

maximum mechanical advantage possible for a hydraulic jack is not limited by the limitations on

screw jacks and can be far greater. After WWII, improvements to the grinding of hydraulic

rams and the use of O ring seals reduced the price of low-cost hydraulic jacks and they became

widespread for use with domestic cars. Screw jacks still remain for minimal cost applications,

such as the little-used tyre-changing jacks supplied with cars.

Page 6

1.4.1.3 Applications

A jackscrew's threads must support heavy loads. In the most heavy-duty applications, such as

screw jacks, a square thread or buttress thread is used, because it has the lowest friction. In other

application such as actuators, an Acme thread is used, although it has higher friction.

The large area of sliding contact between the screw threads means jackscrews have high friction

and low efficiency as power transmission linkages, around 30%–50%. So they are not often used

for continuous transmission of high power, but more often in intermittent positioning

applications.

The ball screw is a more advanced type of leadscrew that uses a recirculating-ball nut to

minimize friction and prolong the life of the screw threads. The thread profile of such screws is

approximately semicircular (commonly a "gothic arch" profile) to properly mate with thebearing

balls. The disadvantage to this type of screw is that it is not self-locking. Ball screws are

prevalent in powered leadscrew actuators.

Jackscrews form vital components in equipment. For instance, the failure of a jackscrew on

a McDonnell Douglas MD80 airliner due to a lack of grease resulted in the crash of Alaska

Airlines Flight 261 off the coast of California in 2000.

The jackscrew figured prominently in the classic novel Robinson Crusoe. It was also featured in

a recent History Channel program as the saving tool of the Pilgrims' voyage – the main

crossbeam, a key structural component of their small ship, cracked during a severe storm. A

farmer's jackscrew secured the damage until landfall.

1.5 RELAYS

Fig. 1.7 Circuit diagram of Relay

Fig. 1.8 Actual diagram of Relay

Page 7

A relay is an electrically operated switch. Current flowing through the coil of the relay creates a

magnetic field, which attracts a lever and changes the switch contacts. The coil current can be on

or off so relays have two switch positions and they are double throw (changeover) switches.

Relays allow one circuit to switch a second circuit that can be completely separate from the

first. For example a low voltage battery circuit can use a relay to switch a 230V AC mains

circuit. There is no electrical connection inside the relay between the two circuits, the link is

magnetic and mechanical.

The coil of a relay passes a relatively large current, typically 30mA for a 12V relay, but it

can be as much as 100mA for relays designed to operate from lower voltages. Most ICs

(chips) cannot provide this current and a transistor is usually used to amplify the small

IC current to the larger value required for the relay coil.

The maximum output current for the popular 555 timer IC is 200mA so these devices can supply

relay coils directly without amplification.

The relay's switch connections are usually labeled COM, NC and NO:

COM = Common, always connect to this, it is the moving part of the switch.

NC = Normally Closed, COM is connected to this when the relay coil is off.

NO = Normally Open, COM is connected to this when the relay coil is on.

Connect to COM and NO if you want the switched circuit to be on when the relay coil is on.

Connect to COM and NC if you want the switched circuit to be on when the relay coil is off.

1.6 DC MOTOR A DC motor is an electric motor that runs on direct current (DC) electricity.

Brushed

The brushed DC motor generates torque directly from DC power supplied to the motor by using

internal commutation, stationary permanent magnets, and rotating electrical magnets.It works on

the principle of Lorentz force , which states that any current carrying conductor placed within an

external magnetic field experiences a torque or force known as Lorentz force. Advantages of a

brushed DC motor include low initial cost, high reliability, and simple control of motor speed.

Disadvantages are high maintenance and low life-span for high intensity uses.

Synchronous

Synchronous DC motors, such as the brushless DC motor and the stepper motor, require external

commutation to generate torque. They lock up if driven directly by DC power. However, BLDC

motors are more similar to a synchronous ac motor.

Brushless

Brushless DC motors use a rotating permanent magnet in the rotor, and stationary electrical

magnets on the motor housing. A motor controller converts DC to AC. This design is simpler

Page 8

than that of brushed motors because it eliminates the complication of transferring power from

outside the motor to the spinning rotor. Advantages of brushless motors include long life span,

little or no maintenance, and high efficiency. Disadvantages include high initial cost, and more

complicated motor speed controllers.

Fig. 1.9 Stepper motor

1.6.1 Working of DC motor

In any electric motor, operation is based on simple electromagnetism. A current-carrying

conductor generates a magnetic field; when this is then placed in an external magnetic field, it

will experience a force proportional to the current in the conductor, and to the strength of the

external magnetic field. As you are well aware of from playing with magnets as a kid, opposite

(North and South) polarities attract, while like polarities (North and North, South and South)

repel. The internal configuration of a DC motor is designed to harness the magnetic interaction

between a current-carrying conductor and an external magnetic field to generate rotational

motion.

Fig. 1.10 Inside view of DC motor

Every DC motor has six basic parts -- axle, rotor, stator, commutator, field magnet(s), and

brushes. In most common DC motors, the external magnetic field is produced by high-strength

permanent magnets1. The stator is the stationary part of the motor -- this includes the motor

casing, as well as two or more permanent magnet pole pieces. The rotor rotate with respect to the

stator. The rotor consists of windings (generally on a core), the windings being electrically

connected to the commutator. The above diagram shows a common motor layout -- with the

rotor inside the stator (field) magnets.

Page 9

CHAPTER-2

MICROCONTROLLER

(MICROCONTROLLER AT89C51/89s52)

2.1 Features:

• Compatible with MCS-51™ Products

• 8K Bytes of In-System Re programmable Flash Memory

• Endurance: 1,000 Write/Erase Cycles

• Fully Static Operation: 0 Hz to 24 MHz

• Three-level Program Memory Lock

• 256 x 8-bit Internal RAM

• 32 Programmable I/O Lines

•Three 16-bit Timer/Counters

• Eight Interrupt Sources

• Programmable Serial Channel

• Low-power Idle and Power-down Modes

Fig. 2.1 Block diagram of microcontroller

Page 10

2.2 Special Function Resistors

A map of the on-chip memory area called the Special Function Register (SFR) space is shown in

Table 1.

Note that not all of the addresses are occupied, and unoccupied addresses may not be

implemented on the chip. Read accesses to these addresses will in general return random data,

and write accesses will have an indeterminate effect. User software should not write 1s to these

unlisted locations, since they may be used in future prod new features. In that case, the reset or

inactive values of the new bits will always be 0.

2.3 Interrupt Resistors

The individual interrupt enable bits are in the IE register. Two priorities can be set for each of the

six interrupt sources in the IP register. Instructions that use indirect addressing access the upper

128 bytes of RAM. For example, the following indirect addressing instruction, where R0

contains 0A0H, accesses the data byte at address 0A0H, rather than P2 (whose address is 0A0H).

MOV @R0, #data

Note that stack operations are examples of indirect addressing, so the upper 128 bytes of data

RAM are avail available as stack space.

2.3.1 Timer 0 and 1

Timer 0 and Timer 1 in the AT89C52 operate the same way as Timer 0 and Timer 1 in the

T89C51.

2.3.2 Timer 2

Timer 2 is a 16-bit Timer/Counter that can operate as either a timer or an event counter. The type

of operation is selected by bit C/T2 in the SFR T2CON (shown in Table 2).Timer 2 has three

operating modes: capture, auto-reload (up or down counting), and baud rate generator. The

modes are selected by bits in T2CON, as shown in Table 3.Timer 2 consists of two 8-bit

registers, TH2 and TL2. In the Timer function, the TL2 register is incremented every machine

cycle. Since a machine cycle consists of 12 oscillator periods, the count rate is 1/12 of the

oscillator input pin, T2. In this function, the external input is sampled during S5P2 of every

machine cycle. When the samples show a high in one cycle and a low in the next cycle, the count

is incremented.

The new count value appears in the register during S3P1 of the cycle following the one in which

the transition was detected. Since two machine cycles (24 oscillator periods) are required to

recognize a 1-to-0 transition, the maximum count rate is 1/24 of the oscillator frequency. To

ensure that a given level is sampled at least once before it changes, the level should be held for at

least one full machine cycle.

Page 11

2.4 Capture Mode

In the capture mode, two options are selected by bit EXEN2 in T2CON. If EXEN2 = 0, Timer 2

is a 16-bit timer or counter which upon overflow sets bit TF2 in T2CON.This bit can then be

used to generate an interrupt. If EXEN2 = 1, Timer 2 performs the same operation, but a 1-to-0

transition at external input T2EX also causes the current value in TH2 and TL2 to be captured

into CAP2H and RCAP2L, respectively. In addition, the transition at T2EX causes bit EXF2 in

T2CON to be set. The EXF2 bit, like TF2, can generate an interrupt. The capture mode is

illustrated in Figure 2.2.

Fig. 2.2 Circuit diagram of capture mode

Page 12

2.5 Auto-reload (Up or Down Counter)

Timer 2 can be programmed to count up or down when configured in its 16-bit auto-reload

mode. This feature is invoked by the DCEN (Down Counter Enable) bit located in the SFR

T2MOD (see Table 4). Upon reset, the DCEN bit is set to 0 so that timer 2 will default to count

up. When DCEN is set, Timer 2 can count up or down, depending on the value of the T2EX pin.

Figure 2 shows Timer 2 automatically counting up when DCEN = 0. In this mode, two options

are selected by bitEXEN2 in T2CON. If EXEN2 = 0, Timer 2 counts up to 0FFFFH and then

sets the TF2 bit upon overflow. The overflow also causes the timer registers to be reloaded with

the 16-bit value in RCAP2H and RCAP2L. The values in Timer in Capture ModeRCAP2H and

RCAP2L are preset by software. If EXEN2 = 1, a 16-bit reload can be triggered either by an

overflow or by a 1-to-0 transition at external input T2EX. This transition also sets the EXF2 bit.

Both the TF2 and EXF2 bits can generate an interrupt if enabled. Setting the DCEN bit enables

Timer 2 to count up or down, as shown in Figure 3. In this mode, the T2EX pin controls the

direction of the count. A logic 1 at T2EX makes Timer 2 count up. The timer will overflow at

0FFFFH and set the TF2 bit. This overflow also causes the 16-bit value in RCAP2H and

RCAP2L to be reloaded into the timer registers, TH2 and TL2, respectively. A Logic 0 at T2EX

makes Timer 2 count down. The timer underflows when TH2 and TL2 equal the values stored in

RCAP2H and RCAP2L. The underflow sets the TF2 bit and causes 0FFFFH to be reloaded into

the timer Registers. The EXF2 bit toggles whenever Timer 2 overflows or underflows and can be

used as a 17th bit of resolution. In this operating mode, EXF2 does not flag an interrupt.

Fig. 2.3 Circuit diagram of up and down counter

Page 13

2.6 Baud Rate Generator

Timer 2 is selected as the baud rate generator by setting TCLK and/or RCLK in T2CON (Table

2). Note that the baud rates for transmit and receive can be different if Timer 2 is used for the

receiver or transmitter and Timer 1 is used for the other function. Setting RCLK and/or TCLK

puts Timer 2 into its baud rate generator mode, as shown in Figure4. The baud rate generator

mode is similar to the auto-reload mode, in that a rollover in TH2 causes the Timer 2 registers to

be reloaded with the 16-bit value in registers RCAP2H and RCAP2L, which are preset by

software.

The baud rates in Modes 1 and 3 are determined by Timer2’s overflow rate according to the

following equation.

The Timer can be configured for either timer or counter operation. In most applications, it is

configured for timer operation (CP/T2 = 0). The timer operation is different for Timer 2 when it

is used as a baud rate generator. Normally, as a timer, it increments every machine cycle (at 1/12

the oscillator frequency).As a baud rate generator, however, it increments every state time (at 1/2

the oscillator frequency).

The baud rate formula is given below.

Where (RCAP2H, RCAP2L) is the content of RCAP2H and RCAP2L taken as a 16-bit unsigned

integer. Timer 2 as a baud rate generator is shown in Figure 4. This figure is valid only if RCLK

or TCLK = 1 in T2CON. Note that a rollover in TH2 does not set TF2 and will not generate an

interrupt. Note too, that if EXEN2 is set, a 1-to-0 transition in T2EX will set EXF2 but will not

cause a reload from (RCAP2H, RCAP2L) to (TH2, TL2). Thus when Timer 2 is in use as a baud

rate generator, T2EX can be used as an extra external interrupt.

Note that when Timer 2 is running (TR2 = 1) as a timer in the baud rate generator mode, TH2 or

TL2 should not be read from or written to. Under these conditions, the Timer is incremented

every state time, and the results of a read or write may not be accurate. The RCAP2 registers

may be read but should not be written to, because a write might overlap a reload and cause write

and/or reload errors. The timer should be turned off (clear TR2) before accessing the Timer 2 or

RCAP2 registers.

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Fig. 2.4 Circuit diagram of Baud Rate Generator

2.7 Programmable Clock Out

A 50% duty cycle clock can be programmed to come out on P1.0, as shown in Figure 5. This pin,

besides being a regular I/O pin, has two alternate functions. It can be programmed to input the

external clock for Timer/Counter 2 or to output a 50% duty cycle clock ranging from 61 Hz to 4

MHz at a 16 MHz operating frequency. To configure the Timer/Counter 2 as a clock generator,

bit C/T2 (T2CON.1) must be cleared and bit T2OE (T2MOD.1) must be set. Bit TR2 (T2CON.2)

starts and stops the timer. The clock-out frequency depends on the oscillator frequency and the

reload value of Timer 2 capture registers (RCAP2H, RCAP2L), as shown in the following

equation.

In the clock-out mode, Timer 2 roll-overs will not generate an interrupt. This behavior is similar

to when Timer 2 is used as a baud-rate generator. It is possible to use Timer 2 as a baud-rate

generator and a clock generator simultaneously. Note, however, that the baud-rate and clock-out

Frequencies cannot be determined independently from one another since they both use RCAP2H

and RCAP2L.

Page 15

Fig. 2.5 Circuit representation of Programmable Clock Out

2.8 Idle Mode Oscillator Characteristics

XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier that can be

configured for use as an on-chip oscillator, as shown in Figure 7. Either a quartz crystal or

ceramic resonator may be used. To drive the device from an external clock source, XTAL2

should be left

Un connected while XTAL1 is driven, as shown in Figure 8.There are no requirements on the

duty cycle of the external clock signal, since the input to the internal clocking circuitry is through

a divide-by-two flip-flop, but minimum and maximum voltage high and low time specifications

must be observed.

In idle mode, the CPU puts itself to sleep while all the on chip peripherals remain active. The

mode is invoked by software. The content of the on-chip RAM and all the special functions

registers remain unchanged during this mode. The idle mode can be terminated by any enabled

interrupt or by a hardware reset.

Note that when idle mode is terminated by a hardware reset, the device normally resumes

program execution from where it left off, up to two machine cycles before the internal reset

algorithm takes control. On-chip hardware inhibits access to internal RAM in this event, but

access to the port pins is not inhibited. To eliminate the possibility of an unexpected write to a

port pin when idle mode is terminated by a reset, the instruction following the one that invokes

idle mode should not write to a port pin or to external memory.

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CHAPTER-3

3.1 POWER DOWN MODE

In the power-down mode, the oscillator is stopped, and the instruction that invokes power-down

is the last instruction executed. The on-chip RAM and Special Function Registers retain their

values until the power-down mode is terminated. The only exit from power-down is a hardware

reset. Reset redefines the SFR s but does not change the on-chip RAM. The reset should not be

cultivated before VCC is restored to its normal operating level and must be held active long

enough to allow the oscillator to restart and stabilize.

Fig. 3.1 Output characteristics of power down mode

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3.1.1 AC Characteristics

Under operating conditions, load capacitance for Port 0, ALE/PROG, and PSEN = 100 pF; load

capacitance for all otheroutputs = 80 Pf.

Fig. 3.2 AC characteristics

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CHAPTER-4

4.1 TRANSFORMERS

A transformer is a device that transfers electrical energy from one circuit to another by magnetic

coupling without requiring relative motion between its parts. It usually comprises two or more

coupled windings, and, in most cases, a core to concentrate magnetic flux. A transformer

operates from the application of an alternating voltage to one winding, which creates a time-

varying magnetic flux in the core. This varying flux induces a voltage in the other windings.

Varying the relative number of turns between primary and secondary windings determines the

ratio of the input and output voltages, thus transforming the voltage by stepping it up or down

between circuits.

4.1.1 Basic principle

The principles of the transformer are illustrated by consideration of a hypothetical ideal

transformer consisting of two windings of zero resistance around a core of negligible reluctance.

A voltage applied to the primary winding causes a current, which develops a magnetomotive

force (MMF) in the core. The current required to create the MMF is termed the magnetising

current; in the ideal transformer it is considered to be negligible. The MMF drives flux around

the magnetic circuit of the core.

Fig. 4.1 The ideal transformer as a circuit element

An electromotive force (EMF) is induced across each winding, an effect known as mutual

inductance. The windings in the ideal transformer have no resistance and so the EMFs are equal

in magnitude to the measured terminal voltages. In accordance with Faraday's law of induction,

they are proportional to the rate of change of flux:

and

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EMF induced in primary and secondary windings

where:

and are the induced EMFs across primary and secondary windings,

aVnd are the numbers of turns in the primary and secondary windings,

and are the time derivatives of the flux linking the primary and secondary windings.

In the ideal transformer, all flux produced by the primary winding also links the secondary, and

so , from which the well-known transformer equation follows:

4.1.2 Transformer Equation

The ratio of primary to secondary voltage is therefore the same as the ratio of the number of

turns; alternatively, that the volts-per-turn is the same in both windings. The conditions that

determine Transformer working in STEP UP or STEP DOWN mode are:

Ns > Np

Fig. 4.2 A step-down transformer

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CHAPTER-5

RECTIFIER

A bridge rectifier is an arrangement of four diodes connected in a bridge circuit as shown

below, that provides the same polarity of output voltage for any polarity of the input voltage.

When used in its most common application, for conversion of alternating current (AC) input into

direct current (DC) output, it is known as a bridge rectifier. The bridge rectifier provides full

wave rectification from a two wire AC input (saving the cost of a center tapped transformer) but

has two diode drops rather than one reducing efficiency over a center tap based design for the

same output voltage.

Fig. 5.1 Schematic diagram of a bridge rectifier

The essential feature of this arrangement is that for both polarities of the voltage at the bridge

input, the polarity of the output is constant.

5.1 Basic Operation

When the input connected at the left corner of the diamond is positive with respect to the one

connected at the right hand corner, current flows to the right along the upper colored path to the

output, and returns to the input supply via the lower one.

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When the right hand corner is positive relative to the left hand corner, current flows along the

upper colored path and returns to the supply via the lower colored path.

Fig. 5.2 Output characteristics of rectifier

In each case, the upper right output remains positive with respect to the lower right one. Since

this is true whether the input is AC or DC, this circuit not only produces DC power when

supplied with AC power: it also can provide what is sometimes called "reverse polarity

protection". That is, it permits normal functioning when batteries are installed backwards or DC

input-power supply wiring "has its wires crossed" (and protects the circuitry it powers against

damage that might occur without this circuit in place).

Prior to availability of integrated electronics, such a bridge rectifier was always constructed from

discrete components. Since about 1950, a single four-terminal component containing the four

diodes connected in the bridge configuration became a standard commercial component and is

now available with various voltage and current ratings.

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5.2 Output Smoothing

For many applications, especially with single phase AC where the full-wave bridge serves to

convert an AC input into a DC output, the addition of a capacitor may be important because the

bridge alone supplies an output voltage of fixed polarity but pulsating magnitude.

Fig. 5.3 Bridge rectifier with smoothen output

5.3 Bridge Rectifier with smoothen output

The function of this capacitor, known as a 'smoothing capacitor' is to lessen the variation in (or

'smooth') the raw output voltage waveform from the bridge. One explanation of 'smoothing' is

that the capacitor provides a low impedance path to the AC component of the output, reducing

the AC voltage across, and AC current through, the resistive load. In less technical terms, any

drop in the output voltage and current of the bridge tends to be cancelled by loss of charge in the

capacitor. This charge flows out as additional current through the load. Thus the change of load

current and voltage is reduced relative to what would occur without the capacitor. Increases of

voltage correspondingly store excess charge in the capacitor, thus moderating the change in

output voltage / current.

The capacitor and the load resistance have a typical time constant τ = RC where C and R are the

capacitance and load resistance respectively.

As long as the load resistor is large enough so that this time constant is much longer than the

time of one ripple cycle, the above configuration will produce a well smoothed DC voltage

across the load resistance. In some designs, a series resistor at the load side of the capacitor is

added. The smoothing can then be improved by adding additional stages of capacitor–resistor

pairs, often done only for sub-supplies to critical high-gain circuits that tend to be sensitive to

supply voltage noise.

Page 23

5.4 Voltage Regulators

A voltage regulator is an electrical regulator designed to automatically maintain a constant

voltage level. It may use an electromechanical mechanism, or passive or active electronic

components. Depending on the design, it may be used to regulate one or more AC or DC

voltages. With the exception of shunt regulators, all voltage regulators operate by comparing the

actual output voltage to some internal fixed reference voltage. Any difference is amplified and

used to control the regulation element. This forms a negative feedbackservo control loop. If the

output voltage is too low, the regulation element is commanded to produce a higher voltage. For

some regulators if the output voltage is too high, the regulation element is commanded to

produce a lower voltage; however, many just stop sourcing current and depend on the current

draw of whatever it is driving to pull the voltage back down. In this way, the output voltage is

held roughly constant. The control loop must be carefully designed to produce the desired

tradeoff between stability and speed of response.

5.4.1 LM7805 (3-Terminal Fixed Voltage Regulator)

The MC78XX/LM78XX/MC78XXA series of three terminal positive regulators are available in

the

TO-220/D-PAK package and with several fixed output voltages, making them useful in a wide

range of applications. Each type employs internal current limiting, thermal shut down and safe

operating area protection, making it essentially indestructible. If adequate heat sinking is

provided, they can deliver over 1A output current. Although designed primarily as fixed voltage

regulators, these devices can be used with external components to obtain adjustable voltages and

currents.

Fig. 5.4 Block diagram of voltage regulator

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5.4.2 Internal block Diagram

Fig. 5.5 Internal block diagram of voltage regulator

5.4.2.1 Features:

• Output Current up to 1A

• Output Voltages of 5, 6, 8, 9, 10, 12, 15, 18, 24V

• Thermal Overload Protection

• Short Circuit Protection

• Output Transistor Safe Operating Area Protection

Page 25

5.5 CRYSTAL OSCILLATOR

It is often required to produce a signal whose frequency or pulse rate is very stable and exactly

known. This is important in any application where anything to do with time or exact

measurement is crucial. It is relatively simple to make an oscillator that produces some sort of a

signal, but another matter to produce one of relatively precise frequency and stability. AM radio

stations must have a carrier frequency accurate within 10Hz of its assigned frequency, which

may be from 530 to 1710 kHz. SSB radio systems used in the HF range (2-30 MHz) must be

within 50 Hz of channel frequency for acceptable voice quality, and within 10 Hz for best

results. Some digital modes used in weak signal communication may require frequency stability

of less than 1 Hz within a period of several minutes. The carrier frequency must be known to

fractions of a hertz in some cases. An ordinary quartz watch must have an oscillator accurate to

better than a few parts per million. One part per million will result in an error of slightly less than

one half second a day, which would be about 3 minutes a year. This might not sound like much,

but an error of 10 parts per million would result in an error of about a half an hour per year. A

clock such as this would need resetting about once a month, and more often if you are the

punctual type. A programmed VCR with a clock this far off could miss the recording of part of a

TV show. Narrow band SSB communications at VHF and UHF frequencies still need 50 Hz

frequency accuracy. At 440 MHz, this is slightly more than 0.1 part per million.

Ordinary L-C oscillators using conventional inductors and capacitors can achieve typically 0.01

to 0.1 percent frequency stability, about 100 to 1000 Hz at 1 MHz. This is OK for AM and FM

broadcast receiver applications and in other low-end analog receivers not requiring high tuning

accuracy. By careful design and component selection, and with rugged mechanical construction,

.01 to 0.001%, or even better (.0005%) stability can be achieved. The better figures will

undoubtedly employ temperature compensation components and regulated power supplies,

together with environmental control (good ventilation and ambient temperature regulation) and

“battleship” mechanical construction. This has been done in some communications receivers

used by the military and commercial HF communication receivers built in the 1950-1965 era,

before the widespread use of digital frequency synthesis. But these receivers were extremely

expensive, large, and heavy. Many modern consumer grade AM, FM, and shortwave receivers

employing crystal controlled digital frequency synthesis will do as well or better from a

frequency stability standpoint.

An oscillator is basically an amplifier and a frequency selective feedback network (Fig 1). When,

at a particular frequency, the loop gain is unity or more, and the total phaseshift at this frequency

is zero, or some multiple of 360 degrees, the condition for oscillation is satisfied, and the circuit

will produce a periodic waveform of this frequency. This is usually a sine wave, or square wave,

but triangles, impulses, or other waveforms can be produced. In fact, several different waveforms

often are simultaneously produced by the same circuit, at different points. It is also possible to

have several frequencies produced as well, although this is generally undesirable.

Page 26

CHAPTER-6

RESISTOR

6.1 TYPES OF RESISTORS

Resistors are used to limit the value of current in a circuit. Resistors offer opposition to the flow

of current. They are expressed in ohms for which the symbol is ‘’. Resistors are broadly

classified as

(1) Fixed Resistors

(2) Variable Resistors

6.1.1 FIXED RESISTORS

The most common of low wattage, fixed type resistors is the molded-carbon composition

resistor. The resistive material is of carbon clay composition. The leads are made of tinned

copper. Resistors of this type are readily available in value ranging from few ohms to about

20M, having a tolerance range of 5 to 20%. They are quite inexpensive. The relative size of all

fixed resistors changes with the wattage rating.

Another variety of carbon composition resistors is the metalized type. It is made by deposition a

homogeneous film of pure carbon over a glass, ceramic or other insulating core. This type of

film-resistor is sometimes called the precision type, since it can be obtained with an accuracy of

1%.

Lead Tinned Copper Material

Colour Coding Molded Carbon Clay Composition

Fig. 6.1 Line diagram of fixed resistor

Page 27

6.1.2 A WIRE WOUND RESISTOR

It uses a length of resistance wire, such as nichrome. This wire is wounded on to a round hollow

porcelain core. The ends of the winding are attached to these metal pieces inserted in the core.

Tinned copper wire leads are attached to these metal pieces. This assembly is coated with an

enamel coating powdered glass. This coating is very smooth and gives mechanical protection to

winding. Commonly available wire wound resistors have resistance values ranging from 1 to

100K, and wattage rating up to about 200W.

6.2 CODING OF RESISTOR

Some resistors are large enough in size to have their resistance printed on the body. However

there are some resistors that are too small in size to have numbers printed on them. Therefore, a

system of colour coding is used to indicate their values. For fixed, moulded composition resistor

four colour bands are printed on one end of the outer casing. The colour bands are always read

left to right from the end that has the bands closest to it. The first and second band represents the

first and second significant digits, of the resistance value. The third band is for the number of

zeros that follow the second digit. In case the third band is gold or silver, it represents a

multiplying factor of 0.1to 0.01. The fourth band represents the manufacture’s tolerance.

6.2.1 RESISTOR COLOUR CHART

Fig. 6.2 Colour coding of resistor

5 green

0 black

1 brown

2 red

3 orange

4 yellow

6 blue

7 purple

8 silver

9 white

0 black

1 brown

2 red

3 orange

4 yellow

6 blue

7 purple

8 silver

9 white

5green 5 green

0 black

1 brown

2 red

3 orange

4 yellow

6 blue

7 purple

8 silver

9 white

5 green

0 black

1 brown

2 red

3 orange

4 yellow

6 blue

7 purple

8 silver

9 white

Page 28

For example, if a resistor has a colour band sequence: yellow, violet, orange and gold

Then its range will be—

Yellow=4, violet=7, orange=10³, gold=±5% =47KΏ ±5% =2.35KΏ

Most resistors have 4 bands:

The first band gives the first digit.

The second band gives the second digit.

The third band indicates the number of zeros.

The fourth band is used to show the tolerance (precision) of the resistor.

This resistor has red (2), violet (7), yellow (4 zeros) and gold bands.

So its value is 270000 = 270 k .

The standard colour code cannot show values of less than 10 . To show these small values two

special colours are used for the third band: gold, which means × 0.1 and silver which means

× 0.01. The first and second bands represent the digits as normal.

For example:

The fourth band of the colour code shows the tolerance of a resistor. Tolerance is the precision of

the resistor and it is given as a percentage. For example a 390 resistor with a tolerance of ±10%

will have a value within 10% of 390 , between 390 - 39 = 351 and 390 + 39 = 429 (39 is

10% of 390).

A special colour code is used for the fourth band tolerance: silver ±10%, gold ±5%, red

±2%, brown ±1%. If no fourth band is shown the tolerance is ±20%.

6.3 VARIABLE RESISTOR

In electronic circuits, sometimes it becomes necessary to adjust the values of currents and

voltages. For n example it is often desired to change the volume of sound, the brightness of a

television picture etc. Such adjustments can be done by using variable resistors.

Although the variable resistors are usually called rheostats in other applications, the smaller

variable resistors commonly used in electronic circuits are called potentiometers.

Page 29

CHAPTER-7

TRANSISTORS

A transistor is an active device. It consists of two PN junctions formed by sandwiching either p-

type or n-type semiconductor between a pair of opposite types.

There are two types of transistor:

1. n-p-n transistor

2. p-n-p transistor

Fig. 7.1 Circuit diagram of n-p-n & p-n-p transistor

An n-p-n transistor is composed of two n-type semiconductors separated by a thin section of p-

type. However a p-n-p type semiconductor is formed by two p-sections separated by a thin

section of n-type.Transistor has two pnjunctions one junction is forward biased and other is

reversed biased. The forward junction has a low resistance path whereas a reverse biased

junction has a high resistance path.

The weak signal is introduced in the low resistance circuit and output is taken from the high

resistance circuit. Therefore a transistor transfers a signal from a low resistance to high

resistance.Transistor has three sections of doped semiconductors. The section on one side is

emitter and section on the opposite side is collector. The middle section is base.

Fig. 7.2 Composition of transistor

TRANSISTOR

BASE

EMITTER

COLLECTOR

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7.1 Emitter: The section on one side that supplies charge carriers is called emitter. The emitter

is always forward biased w.r.t. base.

Fig. 7.3 Representation of emitter, base & collector in transistor

7.2 Base: The middle section which forms two pn-junctions between the emitter and collector

is called base.

7.3 Collector: The section on the other side that collects the charge is called collector. The

collector is always reversed biased.

A transistor raises the strength of a weak signal and thus acts as an amplifier. The weak signal is

applied between emitter-base junction and output is taken across the load Rc connected in the

collector circuit. The collector current flowing through a high load resistance RC produces a

large voltage across it. Thus a weak signal applied in the input appears in the amplified form in

the collector circuit.

7.4 Heat sink

Fig. 7.4 Heat sink

Waste heat is produced in transistors due to the current flowing through them. Heat sinks are

needed for power transistors because they pass large currents. If you find that a transistor is

becoming too hot to touch it certainly needs a heat sink! The heat sink helps to dissipate

(remove) the heat by transferring it to the surrounding air.

Page 31

7.5 CONNECTORS

Connectors are basically used for interface between two. Here we use connectors for having

interface between PCB and 8051 Microprocessor Kit.

There are two types of connectors they are male and female. The one, which is with pins inside,

is female and other is male.

These connectors are having bus wires with them for connection.

For high frequency operation the average circumference of a coaxial cable must be limited to

about one wavelength, in order to reduce multimodal propagation and eliminate erratic reflection

coefficients, power losses, and signal distortion. The standardization of coaxial connectors

during World War II was mandatory for microwave operation to maintain a low reflection

coefficient or a low voltage standing wave ratio.

Seven types of microwave coaxial connectors are as follows:

1.APC-3.5

2.APC-7

3.BNC

4.SMA

5.SMC

6.TNC

7.Type N

Various types of microwave coaxial connectors

Page 32

CHAPTER-8

LED (LIGHT EMITTING DIODE)

A junction diode, such as LED, can emit light or exhibit electro luminescence. Electro

luminescence is obtained by injecting minority carriers into the region of a pn junction where

radiative transition takes place. In radiative transition, there is a transition of electron from the

conduction band to the valence band, which is made possibly by emission of a photon. Thus,

emitted light comes from the hole electron recombination. What is required is that electrons

should make a transition from higher energy level to lower energy level releasing photon of

wavelength corresponding to the energy difference associated with this transition. In LED the

supply of high-energy electron is provided by forward biasing the diode, thus injecting electrons

into the n-region and holes into p-region.

The pn junction of LED is made from heavily doped material. On forward bias condition,

majority carriers from both sides of the junction cross the potential barrier and enter the opposite

side where they are then minority carrier and cause local minority carrier population to be larger

than normal. This is termed as minority injection. These excess minority carrier diffuse away

from the junction and recombine with majority carriers. In LED, every injected electron takes

part in a radiative recombination and hence gives rise to an emitted photon. Under reverse bias

no carrier injection takes place and consequently no photon is emitted. For direct transition from

conduction band to valence band the emission wavelength.

In practice, every electron does not take part in radiative recombination and hence, the efficiency

of the device may be described in terms of the quantum efficiency which is defined as the rate of

emission of photons divided by the rate of supply of electrons. The number of radiative

recombination, that take place, is usually proportional to the carrier injection rate and hence to

the total current flowing.

8.1 LED Materials

One of the first materials used for LED is GaAs. This is a direct band gap material, i.e., it

exhibits very high probability of direct transition of electron from conduction band to valence

band. GaAs has E= 1.44 eV. This works in the infrared region.

GaP and GaAsP are higher band gap materials. Gallium phosphide is an indirect band gap

semiconductor and has poor efficiency because band to band transitions are not normally

observed.

Gallium Arsenide Phosphide is a tertiary alloy. This material has a special feature in that it

changes from being direct band gap material.

Blue LEDs are of recent origin. The wide band gap materials such as GaN are one of the most

promising LEDs for blue and green emission. Infrared LEDs are suitable for optical coupler

applications.

Page 33

8.2 DIODE

The simplest semiconductor device is made up of a sandwich of P-type semi-conducting

material, with contacts provided to connect the p-and n-type layers to an external circuit.

This is a junction Diode. If the positive terminal of the battery is connected to the p-type

material (cathode) and the negative terminal to the N-type material (Anode), a large current

will flow. This is called forward Current or forward biased.

If the connections are reversed, a very little current will flow. This is because under this

condition, the p-type material will accept the electron from the negative terminal of the

battery and the N-type material will give up its free electrons to the battery, resulting in

the state of electrical equilibrium since the N-type material has no more electrons. Thus

there will be a small current to flow and the diode is called Reverse biased. Thus the

Diode allows direct current to pass only in one direction while blocking it is the other

direction. Power diodes are used in concerting AC into DC. In this , current will flow freely

during the first half cycle (forward biased) and practically not at all during the other half

cycle (reverse biased). This makes the diode an effective rectifier, which convert ac into

pulsating dc. Signal diodes are used in radio circuits for detection. Zener diodes are used in

the circuit to control the voltage.

Fig. 8.1 Representation of diode

Fig. 8.2 Power diode & Signal diode

Page 34

8.3 Some common diodes

1. Zener diode.

2. Photo diode.

3.Light Emitting diode.

8.3.1 ZENER DIODE

A zener diode is specially designed junction diode, which can operate continuously without

being damaged in the region of reverse break down voltage. One of the most important

applications of zener diode is the design of constant voltage power supply. The zener diode is

joined in reverse bias to d.c. through a resistance R of suitable value.

8.3.2 PHOTO DIODE

A photo diode is a junction diode made from photo- sensitive semiconductor or material. In such

a diode, there is a provision to allow the light of suitable frequency to fall on the p-n junction. It

is reverse biased, but the voltage applied is less than the break down voltage. As the intensity of

incident light is increased, current goes on increasing till it becomes maximum. The maximum

current is called saturation current.

8.3.3 LIGHT EMITTING DIODE (LED)

When a junction diode is forward biased, energy is released at the junction diode is forward

biased, energy is released at the junction due to recombination of electrons and holes. In case of

silicon and germanium diodes, the energy released is in infrared region. In the junction diode

made of gallium arsenate or indium phosphide, the energy is released in visible region. Such a

junction diode is called a light emitting diode or LED.

8.4 ADVANTAGES OF LEDs

1.Low operating voltage, current, and power consumption makes Leds compatible with

electronic drive circuits. This also makes easier interfacing as compared to filament incandescent

and electric discharge lamps.

2.The rugged, sealed packages developed for LEDs exhibit high resistance to mechanical shock

and vibration and allow LEDs to be used in severe environmental conditions where other light

sources would fail.

3.LED fabrication from solid-state materials ensures a longer operating lifetime, thereby

improving overall reliability and lowering maintenance costs of the equipment in which they are

installed.

4.The range of available LED colours-from red to orange, yellow, and green-provides the

designer with added versatility.

Page 35

LEDs have certain limitations such as:

1. Temperature dependence of radiant output power and wave length.

2. Sensitivity to damages by over voltage or over current.

3. Theoretical overall efficiency is not achieved except in special cooled or pulsed conditions.

There are also two different types of diodes:-

8.5 SEMICONDUCTOR DIODE

A PN junctions is known as a semiconductor or crystal diode.A crystal diode has two terminal

when it is connected in a circuit one thing is decide is weather a diode is forward or reversed

biased. There is a easy rule to ascertain it. If the external CKT is trying to push the conventional

current in the direction of error, the diode is forward biased. One the other hand if the

conventional current is trying is trying to flow opposite the error head, the diode is reversed

biased putting in simple words.

Fig. 8.3 Line diagram of semiconductor diode

8.5.1 Characteristics of Semiconductor diode

1.If arrowhead of diode symbol is positive W.R.T Bar of the symbol, the diode is forward biased.

2.The arrowhead of diode symbol is negative W.R.T bar , the diode is the reverse bias.

When we used crystal diode it is often necessary to know that which end is arrowhead and which

end is bar. So following method are available.

3.Some manufactures actually point the symbol on the body of the diode e. g By127 by 11 4

crystal diode manufacture by b e b.

4.Sometimes red and blue marks are on the body of the crystal diode. Red mark do not arrow

where’s blue mark indicates bar e .g oa80 crystal diode.

Page 36

8.6 ZENER DIODE

It has been already discussed that when the reverse bias on a crystal diode is increased a critical

voltage, called break down voltage. The break down or zener voltage depends upon the amount

of doping. If the diode is heavily doped depletion layer will be thin and consequently the break

down of he junction will occur at a lower reverse voltage. On the other hand, a lightly doped

diode has a higher break down voltage, it is called zener diode.

Fig. 8.4 Line diagram of Zener diode

Fig. 8.5 VI characteristics of Zener diode

Page 37

CHAPTER-9

CAPACITOR

A capacitor or condenser is a passive electronic component consisting of a pair of conductors

separated by a dielectric (insulator). When a potential difference (voltage) exists across the

conductors, an electric field is present in the dielectric. This field stores energy and produces a

mechanical force between the conductors. The effect is greatest when there is a narrow

separation between large areas of conductor; hence capacitor conductors are often called plates.

An ideal capacitor is characterized by a single constant value, capacitance, which is measured in

farads. This is the ratio of the electric charge on each conductor to the potential difference

between them. In practice, the dielectric between the plates passes a small amount of leakage

current. The conductors and leads introduce an equivalent series resistance and the dielectric has

an electric field strength limit resulting in a breakdown voltage.

Capacitors are widely used in electronic circuits to block the flow of direct current while

allowing alternating current to pass, to filter out interference, to smooth the output of power

supplies, and for many other purposes. They are used in resonant circuits in radio frequency

equipment to select particular frequencies from a signal with many frequencies

Fig. 9.1 Various types of Capacitor

Page 38

9.1 THEORY OF OPERATION

Fig. 9.2 Working of parallel plate capacitor

Charge separation in a parallel-plate capacitor causes an internal electric field. A dielectric

(orange) reduces the field and increases the capacitance.

Fig. 9.3 A simple demonstration of a parallel-plate capacitor

A capacitor consists of two conductors separated by a non-conductive region. The non-

conductive substance is called the dielectric medium, although this may also mean a vacuum or a

semiconductordepletion region chemically identical to the conductors. A capacitor is assumed to

be self-contained and isolated, with no net electric charge and no influence from an external

electric field. The conductors thus contain equal and opposite charges on their facing surfaces,

and the dielectric contains an electric field. The capacitor is a reasonably general model for

electric fields within electric circuits.

Page 39

An ideal capacitor is wholly characterized by a constant capacitance C, defined as the ratio of

charge ±Q on each conductor to the voltage V between them

Sometimes charge buildup affects the mechanics of the capacitor, causing the capacitance to

vary. In this case, capacitance is defined in terms of incremental changes:

In SI units, a capacitance of one farad means that one coulomb of charge on each conductor

causes a voltage of one volt across the device.

9.2 Energy storage in capacitor

Work must be done by an external influence to move charge between the conductors in a

capacitor. When the external influence is removed, the charge separation persists and energy is

stored in the electric field. If charge is later allowed to return to its equilibrium position, the

energy is released. The work done in establishing the electric field, and hence the amount of

energy stored, is given by:

9.3 Current-voltage relation

The current i(t) through a component in an electric circuit is defined as the rate of change of the

charge q(t) that has passed through it. Physical charges cannot pass through the dielectric layer of

a capacitor, but rather build up in equal and opposite quantities on the electrodes: as each

electron accumulates on the negative plate, one leaves the positive plate. Thus the accumulated

charge on the electrodes is equal to the integral of the current, as well as being proportional to

the voltage (as discussed above). As with any antiderivative, a constant of integration is added to

represent the initial voltage v (t0).

Page 40

This is the integral form of the capacitor equation,

.

Taking the derivative of this, and multiplying by C, yields the derivative form.

.

The dual of the capacitor is the inductor, which stores energy in the magnetic field rather than the

electric field. Its current-voltage relation is obtained by exchanging current and voltage in the

capacitor equations and replacing C with the inductance L.

9.4 DC circuit configuration

Fig. 9.4 A simple resistor-capacitor circuit demonstrates charging of a capacitor.

A series circuit containing only a resistor, a capacitor, a switch and a constant DC source of

voltage V0 is known as a charging circuit. If the capacitor is initially uncharged while the switch

is open, and the switch is closed at t = 0, it follows from Kirchhoff's voltage law that

Taking the derivative and multiplying by C, gives a first-order differential equation,

Page 41

At t = 0, the voltage across the capacitor is zero and the voltage across the resistor is V0.

The initial current is then i (0) =V0 /R. With this assumption, the differential equation yields

Fig. 9.5 Circuit arrangement of capacitor and resistor

Page 42

CHAPTER 10 GOVERNMENT OF INDIA

MINISTRY OF ROAD TRANSPORT AND HIGHWAYS

NOTIFICATION

Specification of Maximum Gross Vehicle Weight

and the Maximum Safe Axle Weight.

S.O.728(E), dated 18.10.1996.- In exercise of the powers conferred by sub-section

(I) of section 58 of the Motor Vehicles Act,1988 (59 of 1988) and in supercession of the

notification of the Government of India in the Ministry of Surface Transport S.O. No.479 (E),

dated the 4th

July, 1996, the Central Government hereby specifies that in relation to the

transport vehicles (other than motor cabs) of various categories detailed in the Schedule below

the maximum gross vehicle weight and the maximum safe axle weight of each axle of such

vehicles shall, having regard to the size, nature and number of tyres and maximum weight

permitted to be carried by the tyres as per rule 95 of the Central Motor Vehicles Rules,1989,

be- (i) vehicle manufacturers rating of the gross vehicle weight and axle weight

respectively for each make and model as duly certified by the testing agencies for

compliance of rule 126 of the Central Motor Vehicles Rules,1989, or

(ii) the maximum gross vehicle weight and the maximum safe axle weight of each

vehicle respectively as specified in the Schedule below for the relevant category, or

(iii) the maximum load permitted to be carried by the tyre(s) as specified in the rule 95

of the Central Motor Vehicles Rules,1989, for the size and number of the tyres fitted

on the axle (s) of the relevant make and model, whichever is less:

Provided that the maximum gross vehicle weight in respect of all such transport vehicles,

including multi-axle vehicles shall not be more than the sum total of all the maximum safe

axle weight put together subject to the restrictions, if any, on the maximum gross vehicle

weight given in the said schedule.

Transport Vehicles Category Max

GVW

Tonne

Maximum Safe Axle Weight

1 2 3 4 I Rigid Vehicles

(i) Two Axle One tyre on front axle, and

two tyres on rear axle,

9.00 3 tonnes on front axle

6 tonnes on rear axle

(ii) Two Axle Two tyres on each axle

12.0 6 tonnes on front axle

6 tonnes on rearm

axle

(iii) Two Axle Two tyres on front axle,

and Four tyres on rear axle

16.2 6 tonnes on front axle

10.2 tonnes on rear axle

(iv) Three Axle 25.0

Page 43

Two tyres on front axle, and

Eight tyres on rear tandem axle

6 tonnes on front axle 19 tonnes on rear tandem axle

1[(v) Four Axle Four tyres on front axle, and

Eight tyres on rear tandem axle

31.0

12 tonnes on two front axle

19 tonnes on rear tandem axle

II Semi-Articulated Vehicles

(i) Two Axle Tractor

Single Axle Trailer

Tractor:

2 tyres on front axle

4 tyres on rear axle

Trailer:

4 tyres on single axle

26.4

6 tonnes on front axle

10.2 tonnes on rear axle

10.2 tonnes on single trailer

axle

(ii) Two Axle Tractor

Tandem Axle Trailer

Tractor:

2 tyres on front axle

4 tyres on rear axle

Trailer:

8 tyres on tandem axle

35.2

6 tonnes on front axle

10.2 tonnes on rear axle

19 tonnes on tandem axle

(iii) Two Axle Tractor

Three Axle Trailer

Tractor:

2 tyres on front axle

4 tyres on rear axle

Trailer:

12 tyres on 3 axles

40.2

6 tonnes on front axle

10.2 tonnes on rear axle

24 tonnes on 3 axles

(iv) Three Axle Tractor

Single Axle Trailer

Tractor:

2 tyres on front axle

8 tyres on rear axle

Trailer:

8 tyres on single axle

35.2

6 tonnes on front axle

19 tonnes on rear axle

10.2 tonnes on single axle

(v) Three Axle Tractor

Tandem Axle Trailer

Tractor:

2 tyres on front axle

8 tyres on tandem axle

Trailer:

8 tyres on tandem axle

44.0

6 tonnes on front axle

19 tonnes on rear tandem axle

19 tonnes on tandem axle III Truck-Trailer Combinations

(i) Two Axle Truck 36.6

Page 44

Two Axle Trailer

Truck:

2 tyres on front axle

4tyres on rear axle

Trailer:

4 tyres on front axle

4 tyres on rear axle

6 tonnes on front axle

10.2 tonnes on rear axle

10.2 tonnes on front axle

10.2 tonnes on rear axle

(ii) Three Axle

Truck Two

Axle Trailer

Truck:

2 tyres on front axle

8 tyres on rear tandem

axle Trailer:

4 tyres on front

axle 4 tyres on

rear axle

45.4 (restricted to

44.0 tonnes)

6 tonnes on front axle

19 tonnes on rear tandem axle

10.2 tonnes on front axle 10.2 tonnes on rear axle (iii) Three Axle Truck

Three Axle Trailer

Truck:

2 tyres on front axle

4 tyres on rear axle

Trailer:

4 tyres on rear axle

8 tyres on rear tandem axle

45.4 (restricted to

44.0 tonnes)

6 tonnes on front axle

10.2 tonnes on rear axle

10.2 tonnes on front axle

19.0 tonnes on rear tandem

axle (iv) Three Axle Truck

Three Axle Trailer

Truck:

2 tyres on front axle

8 tyres on rear tandem axle

Trailer:

4 tyres on front axle

8 tyres on rear tandem axle

54.2 (restricted to

44.0 tonnes)

6 tonnes on front axle

19 tonnes on rear tandem axle

10.2 tonnes on front axle

19.0 tonnes on rear tandem

axle

Page 45

CHAPTER 11

CONCLUSION

This project is successfully completed and helped us to develop the better understanding about

the controller and made us realize the power of the controller. We can design anything with the

help of the decision making power of the controller.Since this project is embedded project so it

helped us to clear many concepts about the controller.

The developing of this project has been a learning experience for all team members and would

prove as a milestone in their academic career. The achievements of this project are

i. The project has achieved its set target well in “Time” and “Budget”.

ii. Based on cutting edge technology called embedded development which is niche in the

market today and its future is much bright.

iii. The product developed is ready for implementation and can bring financial benefits

too by sale in the market.

So, we conclude that the Advanced Speed Breaker is still far away from the perfect, but we

believe we have laid the groundwork to enable it to improve out of sight.

Page 46

CHAPTER 12

AREA OF UTILITY & FUTURE SCOPE

It can be used in crowd areas contributing towards high paced development of any areas. As we

know most of the crowd area having accident problem. It can be utilize nearby schools colleges

etc.

For safety purpose, preventing accidents on road, there is a conventional method of having

concrete speed breakers on road. In case of conventional concrete speed breakers, they are found

firm all the time on the road. These types of speed breakers are very useful on road but at the

same time, these cause a great change in performance of the vehicles as well. The example

diagram of such conventional concrete speed breaker is (Fig. 1). So why don’t we have such

speed breaker which can reduce the speed and maintain the performance of the vehicle.

Page 47

REFERENCES

1. R.S Khurmi and J.K Gupta, Kinematics of Machine, Eurasia Publishing House ( pvt.)

( Page No. 210-225 )

2. Strength of Material by: Dr. Sadhu Singh, Dhanpat Rai Publications Delhi

(Page No. 215-221)

3. R.S. Khurmi and J.K. Gupta , Machine Design, Eurasia Publishing House ( pvt.) Ltd.

( Page No. 611 - 612, 646-647, 686-688 )

4. Theraja B.L., Electrical Technology vol-II, New Delhi, S. Chand & Co., 2005

( Page No.: 893 – 997, 1016 – 1020 )

5. The World Book Encylopedia vol. II, USA, World Book Inc., 1992

( Page No. 159)

6. PSG Design Data, Coimbatore, PSG College of Tech., 2000.

( Page No. 1.10 – 1.12, 7.21 – 7322 )

Page 48

BIBLIOGRAPHY

1. ADVANCED ENGINEERING

2. NEW SCIENCE EXPERIMENTS

3. ENERGY CONSERVATION TECHNIQUES.