Documentation....to Be Done

8/3/2019 Documentation....to Be Done

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ACKNOWLEDGEMENT

We express our sincere thanks to our principal

Prof.DR.P.RAGHAVULU for the facilities provided to complete the project.

We are indebted to Mr.K.RAMAKRISHNAN [M.Tech] Head of the

Department, for his immense support and encouragement during the time of

Project work. We are obliged to Mr.M.GOPISIVAPRASAD [M.Tech] for

his Valuable suggestions and encouragement while doing the project work.

It gives us unbound pleasure to offer our sincere thanks to

HONEYLABS for their guidance, supervision and encouragement rendered

throughout the project with their experience has helped us in completing the

project work fruitfully in present form.

We thank to everyone from HONEY LABS, and lecturers of SHREE

INSTITUTE OF TECHNICAL EDUCATION.


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ABSTRACT:

Motor control through RF communication is a very interesting application and is widely

used in robotics, electronic toys, automation systems etc. This topic covers the way DC

motors can be driven by using the controls from a distant place. The controls are

transferred from one end to another by employing an RF module.

The RF module used here are STT-433MHz transmitter STR-433 MHz receiver,

HT12e encoder and HT12d decoder. Four switches are provided at the transmitter end, to

control the speed and direction of the dc motor which is connected at the receiver side.

Two push-to-on switches are provided for increasing/decreasing the speed of the motor.

Two more push-to- on switches provided to rotate the motor in clock wise / counter

clock wise direction.

At the receiving end, the RF receiver receives this data, gives it to RF decoder. This

decoder converts the single bit data into 8-bit data and presents it to the micro controller.

Now, it is the job of the controller to read the data and perform the corresponding action

i.e.. to rotate the dc motor clockwise, anticlockwise, increase of decrease the speed of the

dc motor.


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CONTENTS

CHAPTER

PAGE NO

ACKNOWLEDGEMENT

ABSTRACT

1. INTRODUCTION TO EMBEDDED SYSTEMS

1.1 Embedded system

1.2 Special features of embedded system.1.2.1 Application areas.

1.2.2 Consumer appliances.

1.2.3 Office auto machine.

1.3 Peripherals

2. INTRODUCTION TO MICRO CONTROLLER

2.1 A89S51 Microcontroller.

2.2 Features of A89S51 Microcontroller

2.3 Description of A89S51 Microcontroller

3. CIRCUIT DIAGRAM

4. DESCRIPTION OF MODULES

4.1 Block diagram.

4.2 Dc motor

4.3 RF transmitter4.4 RF receiver

4.5 Encoder

4.6 Decoder

4.7 H-Bridge circuit

5. POWER SUPPLY

6. SOURCE CODE


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7. CONCLUSION.

CHAPTER -1

INTRODUCTION TO EMBEDDED SYSTEMS

1.1 WHAT IS AN EMBEDDED SYSTEM?

An embedded system can be defined as a computing device that does a specific

focused job. Appliances such as the air-conditioner, VCD player, DVD player, printer,

fax machine, mobile phone etc. are examples of embedded systems. Each of these

appliances will have a processor and special hardware to meet the specific requirement of

the application along with the embedded software that is executed by the processor for

meeting that specific requirement. The embedded software is also called firm ware.

The desktop/laptop computer is a general purpose computer. You can use it for a variety

of applications such as playing games, word processing, accounting, software

development and so on. In contrast, the software in the embedded systems is always

fixed.

1.2 SPECAIL FEATURES OF EMBEDDED SYSTEMS

Embedded systems do a very specific task; they cannot be programmed to do

different things. . Embedded systems have very limited resources, particularly the

memory. Generally, they do not have secondary storage devices such as the C

DROM or the floppy disk. Embedded systems have to work against some

deadlines. A specific job has to be completed within a specific time. In some

embedded systems, called real-time systems, the deadlines are stringent. Missing

a deadline may cause a catastrophe-loss of life or damage to property. Embedded

systems are constrained for power. As many embedded systems operate through a

battery, the power consumption has to be very low.


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Embedded systems need to be highly reliable. Once in a while, pressing ALT-

CTRL-OEL is OK on your desktop, but you cannot afford to reset your embedded

system.

Some embedded systems have to operate in extreme environmental conditions

such as very high temperatures and humidity.

Embedded systems that address the consumer market (for exam-ple, electronic

toys) are very cost-sensitive: Even a reduction of $0.1 is lot of cost saving,

because thousands or millions systems may be sold.

Unlike desktop computers in which the hardware platform is dominated by Intel

and the operating system is dominated by Microsoft, there is a wide variety of

processors and operating systems for the embedded systems. So, choosing the

right plat-form is the most complex task.

1.2.1 APPLICATION AREAS

Nearly 99 per cent of the processors manufactured end up in embedded systems.

The embedded system market is one of the highest growth areas as these systems are

used in very market segment- consumer electronics, office automation, industrial

automation, biomedical engineering, wireless communication, data communication,

telecommunications, transportation, military and so on.

1.2.2 CONSUMER APPLIANCES:

At home we use a number of embedded systems which include digital camera,

digital diary, DVD player, electronic toys, microwave oven, remote controls for TV and

air-conditioner, VCO player, video game consoles, video recorders etc. Todays high-

tech car has about 20 embedded systems for transmission control, engine spark control,

air-conditioning, navigation etc. Even wristwatches are now becoming embedded


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systems. The palmtops are powerful embedded systems using which we can carry out

many general-purpose tasks such as playing games and word processing.

1.2.3 OFFICE AUTOMATION:

The office automation products using embedded systems are copying machine,

fax machine, key telephone, modem, printer, scanner etc. Industrial automation: Today a

lot of industries use embedded systems for process control. These include

pharmaceutical, cement, sugar, oil exploration, nuclear energy, electricity generation and

transmission. The embedded systems for industrial use are designed to carry out specific

tasks such as monitoring the temperature, pressure, humidity, voltage, current etc., and

then take appropriate action based on the monitored levels to control other devices or to

send information to a centralized monitoring station. In hazardous industrial environment,

where human presence has to be avoided, robots are used, which are programmed to do

specific jobs. The robots are now becoming very powerful and carry out many interesting

and complicated tasks such as hardware assembly.

1.3 PERIPHERALS:

Embedded Systems talk with the outside world via peripherals, such as:

Serial Communication Interfaces (SCI): RS-232,RS-422, RS-485 etc

Synchronous Serial Communication Interface: I2C, JTAG,SPI, SSC and ESSI

Universal Serial Bus (USB)

Networks: Controller Area Network, LonWorks, etc

Timers: PLL(s), Capture/Compare and Time Processing Units

Discrete IO: aka General Purpose Input Output (GPIO)
http://en.wikipedia.org/wiki/RS-232http://en.wikipedia.org/wiki/RS-422http://en.wikipedia.org/wiki/RS-485http://en.wikipedia.org/wiki/I2Chttp://en.wikipedia.org/wiki/JTAGhttp://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bushttp://en.wikipedia.org/wiki/Universal_Serial_Bushttp://en.wikipedia.org/wiki/Controller_Area_Networkhttp://en.wikipedia.org/wiki/LonWorkshttp://en.wikipedia.org/wiki/RS-232http://en.wikipedia.org/wiki/RS-422http://en.wikipedia.org/wiki/RS-485http://en.wikipedia.org/wiki/I2Chttp://en.wikipedia.org/wiki/JTAGhttp://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bushttp://en.wikipedia.org/wiki/Universal_Serial_Bushttp://en.wikipedia.org/wiki/Controller_Area_Networkhttp://en.wikipedia.org/wiki/LonWorks


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CHAPTER -2

INTRODUCTION TO MICROCONTROLLERS

2.1 MICROCONTROLLER:

Microprocessors and microcontrollers are widely used in embedded systems

products. Microcontroller is a programmable device. A microcontroller has a CPU in

addition to a fixed amount of RAM, ROM, I/O ports and a timer embedded all on a single

chip. The fixed amount of on-chip ROM, RAM and number of I/O ports in

microcontrollers makes them ideal for many applications in which cost and space are

critical.

The Intel 8051 is Harvard architecture, single chip microcontroller (C) which

was developed by Intel in 1980 for use in embedded systems. It was popular in the 1980s

and early 1990s, but today it has largely been superseded by a vast range of enhanced

devices with 8051-compatible processor cores that are manufactured by more than 20

independent manufacturers including Atmel, Infineon Technologies and Maxim

Integrated Products.

8051 is an 8-bit processor, meaning that the CPU can work on only 8 bits of data

at a time. Data larger than 8 bits has to be broken into 8-bit pieces to be processed by the

CPU. 8051 is available in different memory types such as UV-EPROM, Flash and NV-

RAM.


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2.2 FEATURES OF AT89S51

8K Bytes of Re-programmable Flash Memory.

RAM is 256 bytes.

4.0V to 5.5V Operating Range.

Fully Static Operation: 0 Hz to 33 MHzs

Three-level Program Memory Lock.

256 x 8-bit Internal RAM.

32 Programmable I/O Lines.

Three 16-bit Timer/Counters.

Eight Interrupt Sources.

Full Duplex UART Serial Channel.

Low-power Idle and Power-down Modes.

Interrupt recovery from power down mode.

Watchdog timer.

Dual data pointer.

Power-off flag.

Fast programming time.

Flexible ISP programming (byte and page mode).

2.3 DESCRIPTION OF MICROCONTROLLER:

The AT89s52 is a low-voltage, high-performance CMOS 8-bit microcomputer

with 8K bytes of Flash programmable memory. The device is manufactured using

Atmels high density nonvolatile memory technology and is compatible with theindustry-standard MCS-51 instruction set. The on chip flash allows the program memory

to be reprogrammed in system or by a conventional non volatile memory programmer.

By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89s52

is a powerful microcomputer, which provides a highly flexible and cost-effective solution

to many embedded control applications.


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In addition, the AT89s52 is designed with static logic for operation down to zero

frequency and supports two software selectable power saving modes. The Idle Mode

stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system

to continue functioning. The power-down mode saves the RAM contents but freezes theoscillator disabling all other chip functions until the next hardware reset.

Fig: Pin diagram

Fig: Block diagram


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2.3 PIN DESCRIPTION:

Vcc Pin 40 provides supply voltage to the chip. The voltage source is +5V.

GND Pin 20 is the ground.

PORT 0:

Port 0 is an 8-bit open drain bidirectional 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. Port 0 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 bidirectional 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 Flash programming and

verification.


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PORT 2:




are externally being pulled low will source current (IIL) 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-bit addresses (MOVX @ RI), Port 2

emits the contents of the P2 Special Function Register. The port also receives the high-

order address bits and some control signals during Flash programming and verification.

PORT 3:




are externally being pulled low will source current (IIL) because of the pull-ups. Port 3

receives some control signals for Flash programming and verification. Port 3 also serves

the functions of various special features of the AT89S52, as shown in the following table.


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RST:

Reset input A high on this pin for two machine cycles while the oscillator is

running resets the device. This pin drives high for 98 oscillator periods after the

Watchdog times out. The DISRTO bit in SFR AUXR (address 8EH) can be used to

disable this feature. In the default state of bit DISRTO, the RESET HIGH out feature is

enabled.

ALE / PROG:

Address Latch Enable (ALE) 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.

PSEN:

Program Store Enable (PSEN) is the read strobe to external program memory.

When the AT89S52 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:


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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 alsoreceives the 12-volt programming enable voltage (VPP) during Flash programming.

XTAL1:

Input to the inverting oscillator amplifier and input to the internal clock operatingcircuit.

XTAL2:

Output from the inverting oscillator amplifier.

Oscillator Connections:

C1, C2 = 30 pF 10 pF for Crystals = 40 pF 10 pF for Ceramic Resonators

External Clock Drive Configuration:

XTAL1 and XTAL2 are the input and output, respectively, of an inverting

amplifier that can be configured for use as an on-chip oscillator. Either a quartz crystal or

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

XTAL2 should be left unconnected while XTAL1 is driven. There are no requirements

on the duty cycle of the external clock signal, since the input to the internal clocking


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circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high

and low time specifications must be observed.


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CHAPTER -4

DESCRIPTION OF MODULES

3.1 BLOCK DIAGRAM:


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3.2 DCMOTOR

An electric motor is a machine which converts electrical energy into mechanical

energy.

In the DC motor we have only + and leads. Connecting them to a DC voltage source

moves the motor in one direction .By reversing the polarity, the DC motor will move in

opposite direction. The maximum speed of a DC motor is indicated in rpm and it has two

rpm, no-load and loaded. The no load rpm can be from a few thousand to tens of

thousands. The rpm is reduced with moving a load and decreases as the load is increased.


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

motor by using internal commutation, stationary magnets (permanentor, electromagnets),

and rotating electrical magnets.

Like all electric motors or generators, torque is produced by 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 from outside the motor to the spinning wire

windings of the rotor inside the motor.

Brushless DC motors use a rotating permanent magnet or soft magnetic core in the rotor,

and stationary electrical magnets on the motor housing. A motor controller converts DC

toAC. 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. Some such brushless motors are sometimes referred to as "synchronous

motors" although they have no external power supply to be synchronized with, as would

be the case with normal AC synchronous motors.

There are three types of connections used for DC electric motors: series, shunt and compound.

These types of connections configure how the motor's field and armature windings are connected

together. The type of connection is significant because it determines the characteristics of the

motor and is selected for speed/torque requirements of the load.[1]

[edit]Series connection

A series DC motor connects the armature and field windingsin series with a common D.C. power

source. This motor has poor speed regulation since its speed/torque response varies with the

load. However, a series DC motor has very high starting torque and is commonly used for starting

high inertia loads, such as trains, elevators or hoists.[2] The series DC motor is dangerous to

operate unloaded because as its load decreases, its speed increases. In a no-load condition, the
http://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/DC_motor#cite_note-0http://en.wikipedia.org/w/index.php?title=DC_motor&action=edit&section=5http://en.wikipedia.org/w/index.php?title=DC_motor&action=edit&section=5http://en.wikipedia.org/wiki/Armature_(electrical_engineering)http://en.wikipedia.org/wiki/Field_coilhttp://en.wikipedia.org/wiki/Field_coilhttp://en.wikipedia.org/wiki/DC_motor#cite_note-1http://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/DC_motor#cite_note-0http://en.wikipedia.org/w/index.php?title=DC_motor&action=edit&section=5http://en.wikipedia.org/wiki/Armature_(electrical_engineering)http://en.wikipedia.org/wiki/Field_coilhttp://en.wikipedia.org/wiki/DC_motor#cite_note-1


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motor will increase its speed until the motor mechanically destroys itself. This is called a runaway

condition.

[edit]Shunt connection

A shunt DC motor connects the armature and field windings in parallel or shunt with a common

D.C. power source. This type of motor has good speed regulation even as the load varies, but

does not have as high of starting torque as a series DC motor.[3]It is typically used for industrial,

adjustable speed applications, such as machine tools, winding/unwinding machines and

tensioners.

[edit]Compound connection

A compound DC motor connects the armature and fields windings in a shunt and a series

combination to give it characteristics of both a shunt and a series DC motor.[4]This motor is used

when both a high starting torque and good speed regulation is needed. The motor can be

connected in two arrangements: cumulatively or differentially. Cumulative compound motors

connect the series field to aid the shunt field, which provides higher starting torque but less speed

regulation. Differential compound DC motors have good speed regulation and are typically

operated at constant speed. They are commonly used in elevators, air compressors, conveyors

and punch presses.
http://en.wikipedia.org/w/index.php?title=DC_motor&action=edit&section=6http://en.wikipedia.org/w/index.php?title=DC_motor&action=edit&section=6http://en.wikipedia.org/wiki/DC_motor#cite_note-2http://en.wikipedia.org/wiki/DC_motor#cite_note-2http://en.wikipedia.org/w/index.php?title=DC_motor&action=edit&section=7http://en.wikipedia.org/w/index.php?title=DC_motor&action=edit&section=7http://en.wikipedia.org/wiki/DC_motor#cite_note-3http://en.wikipedia.org/wiki/DC_motor#cite_note-3http://en.wikipedia.org/w/index.php?title=DC_motor&action=edit&section=6http://en.wikipedia.org/wiki/DC_motor#cite_note-2http://en.wikipedia.org/w/index.php?title=DC_motor&action=edit&section=7http://en.wikipedia.org/wiki/DC_motor#cite_note-3


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POWERSUPPLY

Power supply is a reference to a soure of electric power. A device or system that

supplies electrical of other types of energy to an output load or group of loads is called a

power supply unit. The term is most commlly applied to electrical energy supplies, less

often to mechanical ones,and rarley to others,

Electrical powersupplies

The term covers the power distribution toghether with any other primary or

secondary sources of energy such as;

Conversion of one form of electrical power to another desired form and voltage.

This typically involves ,converting 120 or 240 volts AC supplied by a utility

company to a well regulated lower voltage DC for electronic devices. For

examples switch mode power supply,linear regulator,rectifier and inverter.

Batteries.

Chemical fuel cells and other forms of energy storage systems

Solar power

Low voltage, low power DC power supply units are commonly integrated with

the devices they supply,such as computers and household electronics.

Constraints that commonly aggect power supplioes ate the amount of power they can

supply,how long they can supply,it without needing some kind of tefueking of


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recharging,how stable their output voltage of current is under varying load conditions and

whether they provide continous power or pulses.

The regulation of power supplies is done by incorporating circuitary to tightly control the

output voltage and current og the power supply to a specific value. The specific vlue is

closely maintain despite variations in the load presented to the power supplys output,

any reasonble voltage variation at the power supplys input. This kind of regulation is

commnly categorized as a stabilized power supply.


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Power supply types

Power supplies for electrronic devices can be broadly divided into linear and switching

power supplies. This linear supply is relatively simple design that becomes increasingly

bulky and heavy for high amperage devices,volgate regulation in a linear supply can

result in low efficiency. A switched mode supply of the same rating as a linear supply

will be smaller,usually more efficient,but will be more complex.

Linear power supply

An AC powered linear power supply usually uses a transformer to convert

the voltage from the wall outlet to a different,usually to low voltage. If it is used to

produce DC a rectifier is used. A capacitor is used to smooth direct current will

remain,which is known as ripple. The pulsations occur at a frequency related to the AC

power supply frequency.

The voltage produced by an unregulated power supply will vary depending

on the load and on varations in the AC supply voltage. For critical electronic applications

a linear regulator will be used to stabilize and adjust the voltage. This regulator will also

greatly reduce the ripple and noise in the output DC current. Linear regulators often

provide,current limiting,protecting the power supply and attached cilrcuit from over

current.

Adjustable linear power supplies are common laboratory and service shop test

equipment,allowing output voltage to be set over a wide range. For example, a bench

power supplies used by circuit designers may be adjustable upto 30v,andupto 5A

output.some can be driven by an external signal.

The simplest power supply circuit consists of a single diode and resistor in

series with the AC supply. This circuit is common in rechargable flashlights.

Switched mode power supply

A smps works on diferent principle. AC mains input is directly rectified without

the use of a transformer, to obtain a DC voltage. This voltage is then sliced into small


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pieces by a high speed electonic switch. The size of these slices grow larger as power

output requirements increases.

The input power slices occur at a very high speed. High frequency,and high voltage in

this first stage permit much smaller stepdown transformers than in a linear powersupply.

After the transformer secondary, the ac is again rectified to DC. To keep output voltage

constant,the power supplies needs a sophisticated feedback controller to monitor current

draw by the load.

Modern switched mode power supplies often include additional saftey features such as

the crowbar circuit to help protect the devices and the user from harm. In the event that

an abnormal high ampearage power draw is detected, the switched mode supply can

assume this is a direct shot and itself down before damage is done. For decades pc

computer power supplies have also provided a power good signal to the motherboard

which prevents operation when abnormal supply voltages are present.

Switched mode powersuppliers have an absolute limit on their minimum ampearage

output. They are only able to output above certain wattage and cannot function below that

point. In a no load condition the frequency of the power slicing circuits increases to a

greater speed,causing the isolation transformer to acts as a teals coil, causing damage due

to the resulting very high voltage power spikes. Switched mode supplies with protection

circuits may briefly turn on,but then shut down,when no load has been detected. A very

small low wattage dummy load such as a ceramic power resistor or 10 watt light bulb can

be attached to the supply to allow it to run with no primary load attached.

Powerfactor has become a recent issue of concern for computer manufacturers.

Switched mode power supplies have traditionally been a source of power line harmonics

and have a very power factor. Many computer power supplies built in the last few years

now include power factor correction built right into the switched mode supply,and may

advertise,the fact that they offer 1.0 power factor.


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APPLICATIONS:


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CONCLUSION

From this project we conclude that the speed of DC motor can be controlled by

using the PWM technique. This circuit is used to controls the drive electric current of themotor for the conrol voltage to become a regulation value. We can use this circuit in

various ways like water supply,etc... Here we can control the input voltage through the

supply electric current of the motor. Finally we are successful in achieving the output of

project.

www.electronicsforyou.com

www.electronicstutorials.com

www.alldatasheets.com

www.google.com

www.8051project.net

www.allcircuits.com
http://www.electronicsforyou.com/http://www.electronicstutorials.com/http://www.alldatasheets.com/http://www.google.com/http://www.8051project.net/http://www.allcircuits.com/http://www.electronicsforyou.com/http://www.electronicstutorials.com/http://www.alldatasheets.com/http://www.google.com/http://www.8051project.net/http://www.allcircuits.com/


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Documents

Documentation....to Be Done