HAZRAT PROJECT

A PROJECT REPORT
ON
ADVANCED SPEED BREAKER
Submitted In Partial Fulfilment Of The Requirement For The Degree
Awarded Of
Bachelor of Technology
In
MECHANICAL ENGINEERING
IIMT ENGINEERING COLLEGE (127), MEERUT
Department Of Mechanical Engineering
Under the guidance of Submitted By:-
Mr. NAVNEET DEWAL MD MASHUQUERAZA (1212740107)
(Asst.Prof.Deptt.ME) HAZRAT ALI (1212740084)
GURJINDERSINGH (1212740081)
MOHD. AZAM (1212740119)
MOHD. ISLAMUDDIN (1212740120)
CHANDRA PARKASH (1212740064)

IIMT ENGINEERING COLLEGE, MEERUT
DEPARTMENT OF MECHANICAL ENGINEERING
CERTIFICATE
This is certified that Project Report entitled “ADVANCED SPEED BREAKER”
Which is submitted by GURJINDER SINGH, HAZRAT ALI, MD MASHUQUE
RAZA,MOHD.ISLAMMUDDIN,CHANDRA PARKASH, MOHD. AZAM in partial
fulfilment of the requirement for the award of the degree of Bachelor of
Technology in department of MECHANICAL ENGINEERING of Dr. A.P.J.
Abdul Kalam Technical University, is a record of the candidates own work
carried out by them under my supervision. The matter embodied in this thesis
is original and has not been submitted for the award of any other degree.
SIGNATURE SIGNATURE
MR.HARI OM SHARMA MR.NAVNEET DEWAL
[HEAD OF DEPARTMENT] [PROJECT GUIDE, ASST.PROF]
MECHANICAL ENGG. MECHANICAL ENGG.

IIMT ENGG.COLLEGE IIMT ENGG.COLLEGE
GANGA NAGAR,MEERUT GANGA NAGAR,MEERUT
ACKNOWLEDGEMENT
We express our sincere gratitude to Mr. NAVNEET DEWAL, Asst. Prof.
Mechanical Engineering Dept. IIMT ENGG. COLLEGE for his stimulating
guidance continuous encouragementand supervision throughoutthe courseof
present work.
We also wish to extend my thanks to other faculty members and
colleagues for attending our project and their insightful comments and
constructive suggestions to improve the quality of this research work.
We are extremely thankful to our Director Dr. A. K. CHAUHAN for her kind
approval of our project. Also to Asst. Prof. Mr. HARI OM SHARMA, Head of
Dept. of Mechanical Engineering ,IIMTENGINEERING COLLEGE,for providing us
infrastructural facilities to work in, without which this work would not have
been possible.
At least not last we would like to thank the persons who are connected to the
project work who was associated to the project.
Thank you

PREFACE
My Dear sir,
We are extremely happy to come out with “PROJECT REPORT ON
ADVANCED SPEED BREAKER” for partial fulfilment in degree of
technology, Mechanical Engineering . This project report has been
strictly as per the requirement and need to domestic and industrial
purpose in modern context. Every kind of care has been taken to write
the subject matter of each topic in simple and lucid manner. The topic is
divided in too many topic has been arranged in a proper sequence to
ensure smooth flow of the subject . Each point is explained in depth
with the help of net and self-explanatory sketches. So, we are sure that
this topic will meet all the minute requirements of the project.

ABSTRACT
As in today’s world, 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.
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.

A
PROJECT REPORT
ON
ADVANCED SPEED BREAKER
ACTUAL VIEW OF PROJECT

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.

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

HARDWARE REQUIREMENTS:
1) Wood structure
2) Speed breaker
3) Metal rod
4) Motor
5) Pole
6) Relay
7) Controlling cards
8) BUZZER
9) LEDs

BLOCK DIAGRAM
CONTROL UNIT
POWER SUPPLY
SENSOR
RED LEDs
Motor to rotate
speed breaker
SOUND
SYSTEM

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.

RELAYS
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.
Circuit symbolfor a relay
Relays
Photographs © Rapid Electronics

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.
Relays are usually SPDT or DPDT but they can have many more sets of
switch contacts, for example relays with 4 sets of changeover contacts are
readily available. For further information about switch contacts and the terms
used to describe them please see the page on switches.
Most relays are designed for PCB mounting but you can solder wires directly to
the pins providing you take care to avoid melting the plastic case of the relay.
The supplier's catalogue should show you the relay's connections. The coil will
be obvious and it may be connected either way round. Relay coils produce
brief high voltage 'spikes' when they are switched off and this can destroy
transistors and ICs in the circuit. To prevent damage you must connect a
protection diode across the relay coil.
The animated picture shows a working relay with its coil and switch contacts.
You can see a lever on the left being attracted by magnetism when the coil is a
switched on. This lever moves the switch contacts. There is one set of contacts
(SPDT) in the foreground and another behind them, making the relay DPDT.

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.
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. Maintenance involves regularly replacing the brushes and
springs which carry the electric current, as well as cleaning or replacing the
commutator. These components are necessary for transferring electrical
power fromoutside the motor to the spinning wire windings of the rotor inside
the motor.

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 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 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.

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 proportionalto
the currentin 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.
Every DC motor has six basic parts -- axle, rotor (a.k.a., armature), stator,
commutator, field magnet(s), and brushes. In most common DC motors (and
all that BEAMers will see), 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 (together with the axle and attached commutator) rotate
with respect to the stator. The rotor consists of windings (generally on a core),
the windings being electrically connected to the commutator.The diagram
shows a common motor layout- with the rotor inside the stator magnets.

MICROCONTROLLER:
MICROCONTROLLER AT89C51/89s52
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

The Power-down mode saves the RAM contents but Freezes the oscillator,
disabling all other chip functions until the next hardware reset.

Pin Description
VCC
Supply voltage.

GND Ground.
Port 0
Port 0 is an 8-bit open drain bi-directional I/O port. As an output port, each pin
can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be
used as high impedance inputs.
Port0 can also be configured to be the multiplexed low order address/data bus
during accesses to external program and data memory. In this mode, P0 has
internal pull-ups.
Port 0 also receives the code bytes during Flash programming and outputs the
code bytes during program verification. External pull-ups are required during
program verification.
Port 1
Port 1 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 1
output buffers can sink/source four TTL inputs. When 1s are written to Port 1
pins, they are pulled high by the internal pull-ups and can be used as inputs. As
inputs, Port 1 pins that are externally being pulled low will source current (IIL)
because of the internal pull-ups.
In addition, P1.0 and P1.1 can be configured to be the timer/counter 2 external
count input (P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX),
respectively, as shown in the following table.
Port 1 also receives the low-order address bytes during

Port 2
because of the internal pull-ups. Port 2 emits the high-order address byte
during fetches from external program memory and during accesses to external
data memory that uses 16-bit addresses (MOVX @ DPTR). In this application,
Port 2 uses strong internal pull-ups when emitting 1s. During accesses to
external data memory that uses 8-bitaddresses (MOVX @ RI), Port 2 emits the
contents of the P2 Special Function Register. Port 2 also receives the high-
order address bits and some control signals during Flash programming and
verification.
Port 3
because of the pull-ups. Port 3 also serves the functions of various special
features of the AT89C51, as shown in the following table. Port 3 also receives
some control signals for Flash programming.

RST
Reset input. A high on this pin for two machine cycles while the oscillator is
running resets the device.
ALE/PROG
Address Latch Enable is an output pulse for latching the low byte of the
address during accesses to external memory. This pin is also the program pulse
input (PROG) during Flash programming. In normal operation, ALE is emitted at
a constant rate of 1/6 the oscillator frequency and may be used for external
timing or clocking purposes. Note, however, that one ALE pulse is skipped
during each access to external data memory. If desired, ALE operation can be
disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only
during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high.
Setting the ALE-disable bit has no effect if the micro controller is in external
execution mode.
PSEN
Program Store Enable is the read strobe to external program memory. When
the AT89C52 is executing code from external program memory, PSEN is

activated twice each machine cycle, except that two PSEN activations are
skipped during each access to external data memory.
EA/VPP
External Access Enable. EA must be strapped to GND in order to enable the
device to fetch code from external program memory locations starting at
0000H up to FFFFH.
Note, however, that if lock bit 1 is programmed, EA will be internally latched
on reset.
EA should be strapped to VCC for internal program executions. This pin also
receives the 12-volt programming enable voltage (VPP) during Flash
programming when 12-volt programming is selected.
XTAL1
Input to the inverting oscillator amplifier and input to the internal clock
operating circuit.
XTAL2
Output from the inverting oscillator amplifier .
Special Function Registers
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 softwareshould 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.
Timer 2 Registers
Control and status bits are contained in registers T2CON (shown in Table 2)
and T2MOD (shown in Table 4) for Timer 2. The register pair (RCAP2H, RCAP2L)
are the Capture/Reload registers for Timer 2 in 16-bit capture mode or 16-bit
auto-reload mode.
Interrupt Registers
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.

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.
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.

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 1.
Auto-reload(Upor 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 theDCEN (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.

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.
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.
UART
The UART in the AT89C52 operates the sameway as the UART in the AT89C51.
Interrupts
The AT89C52 has a total of six interrupt vectors: two external interrupts (INT0
and INT1), three timer interrupts (Timers 0, 1, and 2), and the serial port
interrupt. These interrupts are all shown in Figure 6.Each of these interrupt
sources can be individually enabled or disabled by setting or clearing a bit in
Special Function Register IE. IE also contains a global disable bit, EA, which
disables all interrupts at once.
Note that Table shows thatbit position IE.6 is unimplemented. In the AT89C51,
bit position IE.5 is also unimplemented. User software should not write 1s to
these bit positions, since they may be used in future AT89 products. Timer 2

interrupt is generated by the logical OR of bits TF2 and EXF2 in register T2CON.
Neither of these flags is cleared by hardware when the service routine is
vectored to. In fact, the service routine may have to determine whether it was
TF2 or EXF2 that generated the interrupt, and that bit will have to be cleared in
software. The Timer 0 and Timer 1 flags, TF0 and TF1, are set at S5P2 of the
cycle in which the timers overflow. The values are then polled by the circuitry
in the next cycle. However, the Timer 2 flag, TF2, is set at S2P2 and is polled in
the same cycle in which the timer overflows.

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
Figure7. Either a quartz crystalor 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.
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.

AC Characteristics
Under operating conditions, load capacitance for Port 0, ALE/PROG, and PSEN
= 100 pF; load capacitance for all other outputs = 80 pF.

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. Itusually 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.
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.

Figure 26: 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 haveno 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
Equation 7: EMF inducedin primary and secondary windings
where:
and are the induced EMFs across primary and secondary windings,
and 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, allflux produced by the primary winding also links the
secondary, and so , from which the well-known transformer
equation follows:

Equation 8: 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
Equation 9: Conditon for STEP UP
Ns > Np
Equation 10: Conditon for STEP DOWN
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.

Figure 9: Schematic 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.
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.

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.
Figure 10: AC, half-wave and full wave rectified signals

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.
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.
Figure 11: Bridge Rectifier with smoothen output

The function of this capacitor, known as a 'smoothing capacitor' (see also filter
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
andvoltage 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.

Voltage Regulators
A voltage regulator is an electrical regulator designed to automatically
maintain a constantvoltage level. Itmay 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
shuntregulators, 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 feedback
servo 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.
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.
Figure 18: Internal block Diagram
Figure 19 : Fixed Output Regulator

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
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 severalminutes. 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.
RESISTOR
Resistors areused to limit the value of currentin a circuit. Resistors offer
opposition to the flow of current. They are expressed in ohms for which the
symbolis ‘’. Resistors arebroadly classified as
(1) Fixed Resistors
(2) Variable Resistors
FixedResistors:
The most common of low wattage, fixed type resistors is the molded-carbon
composition resistor. The resistivematerial is of carbon clay composition. The
leads are made of tinned copper. Resistors of this type are readily available in
value ranging fromfew 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. Itis 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
Fixed Resistor
A Wire Wound Resistor :
Ituses a length of resistancewire, such as nichrome. This wireis 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 haveresistancevalues
ranging from1 to 100K, and wattagerating up to about 200W.
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.
RESISTOR COLOUR CHART
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.
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 white5 green
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

This resistor has red (2), violet (7), yellow (4 zeros) and gold bands.
So its value is 270000 =270 k .
The standard colour code cannotshow 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. Thefirst and second bands representthe
digits as normal.
For example:
red, violet, gold bands represent27 × 0.1 = 2.7
blue, green, silver bands represent56 × 0.01 = 0.56
The fourth band of the colour code shows thetolerance 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 havea 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%.

VARIABLE RESISTOR:In electronic circuits, sometimes it becomes necessary
to adjustthe values of currents and voltages. For n example it is often desired
to change the volumeof 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.
TRANSISTORS
A transistor is an active device. Itconsists 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
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 pn
junctions 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 resistancecircuit and output is taken
fromthe high resistancecircuit. Thereforea transistor transfers a signalfrom a
low resistanceto high resistance.
Transistor has three sections of doped semiconductors. Thesection on one
side is emitter and section on the opposite side is collector. The middle section
is base.
Emitter : The section on one side that supplies charge carriers is called
emitter. The emitter is always forward biased w.r.t. base.
Collector : The section on the other side that collects the charge is called
collector. The collector is always reversed biased.

Base : The middle section which forms two pn-junctions between the emitter
and collector is called base.
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.
Heat sink
Waste heat is produced in transistors dueto the currentflowing 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.
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.
Seventypes of microwave coaxial connectors are as follows:
1.APC-3.5
2.APC-7
3.BNC
4.SMA
5.SMC
6.TNC
7.TypeN
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 fromthe conduction band to the valence band,
which is made possibly by emission of a photon. Thus, emitted light comes

fromthe hole electron recombination. What is required is that electrons
should make a transition fromhigher 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 thediode, thus injecting electrons into the n-
region and holes into p-region.
The pn junction of LED is made fromheavily doped material. On forward
bias condition, majority carriers fromboth sides of the junction cross the
potential barrier and enter the opposite sidewhere they are then minority
carrier and causelocal minority carrier population to be larger than normal.
This is termed as minority injection. These excess minority carrier diffuseaway
fromthe junction and recombine with majority carriers.
In LED, every injected electron takes partin a radiative recombination and
hence gives riseto an emitted photon. Under reversebias 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 proportionalto the carrier injection rate and hence to the
total currentflowing.

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 mostpromising LEDs for blue and green emission. Infrared LEDs are
suitable for optical coupler applications.
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 10. Diode
Fig 11. 4008 Diode
Some common diodes are:-
1. Zener diode.
2. Photo diode.

3. Light Emitting diode.
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.
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.
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 caseof 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.

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.
5.LEDs have low inherent noise levels and also high immunity to externally
generated noise.
6.Circuitresponseof LEDs is fast and stable, without surgecurrents or the prior
“warm-up”, period required by filament light sources.
7.LEDs exhibit linearity of radiant power output with forward current over a
wide range.
LEDs have certainlimitations suchas:
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:-
ACTIVE COMPONENT-
Active component are those component for not any other component
are used its operation. I used in this project only function diode, these
component description are described as bellow.
SEMICONDUCTOR DIODE-
A PN junctions is known as a semiconductor or crystaldiode.A crystaldiode 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 conventionalcurrent 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.
1.If arrowhead of diodesymbolis positive W.R.TBar of the symbol, the diode
is forward biased.
2.The arrowhead of diode symbolis negative W.R.Tbar , the diode is the
reversebias.
When we used crystaldiode it is often necessary to know that which end is
arrowhead and which end is bar. So following method are available.
1.Somemanufactures actually point the symbolon the body of the diode e. g
By127 by 11 4 crystaldiode manufactureby b e b.

2.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.
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
A properly doped crystal diode, which has a sharped break down voltage, is
known as a zenor diode.
In this project I used semiconducter diode for bridge rectifies, two-crystal
diode.

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.

Theory of operation
Main article: Capacitance
Charge separation in a parallel-plate capacitor causes an internal electric field.
A dielectric (orange) reduces the field and increases the capacitance.
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 semiconductor depletion 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.
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.
Energy storage
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:

Current-voltage relation
The current i(t) through a component in an electric circuit is defined as the rate
of change of the chargeq(t) that has passed through it. Physicalcharges 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). This is the
integral form of the capacitor equation,
.
Taking the derivative of this, and multiplying by C, yields the derivativeform,[12]
.
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.

DC circuits
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,
At t = 0, the voltage across thecapacitor 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

whereτ0 = RC is the time constantof the system.
As the capacitor reaches equilibrium with the sourcevoltage, the voltage
across the resistor and the currentthrough the entire circuit decay
exponentially. The caseof discharging a charged capacitor likewise
demonstrates exponential decay, but with the initial capacitor voltage
replacing V0 and the final voltage being zero.
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.

REFERENCES
1. R.S. Khurmi and J.K.Gupta, Kinematics of Machine, Eurasia Publishing House
( pvt.)
2. Strength of Material by: Dr. Sadhu Singh, Danpat Publications Delhi
3. R.S. Khurmiand J.K. Gupta , Machine Design, Eurasia Publishing House ( pvt.)
Ltd
4. Theraja B.L., Electrical Teachnology vol.II, New Delhi, S. Chand & Co., 2005
5. The World Book Encylopedia vol. II, USA, World Book Inc., 1992
6. PSG Design Data, Coimbatore, PSG College of Tech., 2000.
BIBLIOGRAPHY
1. ADVANCED ENGINEERING
2. NEW SCIENCEEXPERIMENTS
3. ENERGY CONSERVATIONTECHNIQUES.

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