documentation....to be done
TRANSCRIPT
-
8/3/2019 Documentation....to Be Done
1/26
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.
-
8/3/2019 Documentation....to Be Done
2/26
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.
-
8/3/2019 Documentation....to Be Done
3/26
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
-
8/3/2019 Documentation....to Be Done
4/26
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.
-
8/3/2019 Documentation....to Be Done
5/26
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
-
8/3/2019 Documentation....to Be Done
6/26
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 -
8/3/2019 Documentation....to Be Done
7/26
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.
-
8/3/2019 Documentation....to Be Done
8/26
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.
-
8/3/2019 Documentation....to Be Done
9/26
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
-
8/3/2019 Documentation....to Be Done
10/26
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.
-
8/3/2019 Documentation....to Be Done
11/26
PORT 2:
Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 2 output
buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are
pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 2 pins that
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:
Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output
buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins, they are
pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 3 pins that
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.
-
8/3/2019 Documentation....to Be Done
12/26
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:
-
8/3/2019 Documentation....to Be Done
13/26
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
-
8/3/2019 Documentation....to Be Done
14/26
circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high
and low time specifications must be observed.
-
8/3/2019 Documentation....to Be Done
15/26
CHAPTER -4
DESCRIPTION OF MODULES
3.1 BLOCK DIAGRAM:
-
8/3/2019 Documentation....to Be Done
16/26
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.
-
8/3/2019 Documentation....to Be Done
17/26
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§ion=5http://en.wikipedia.org/w/index.php?title=DC_motor&action=edit§ion=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§ion=5http://en.wikipedia.org/wiki/Armature_(electrical_engineering)http://en.wikipedia.org/wiki/Field_coilhttp://en.wikipedia.org/wiki/DC_motor#cite_note-1 -
8/3/2019 Documentation....to Be Done
18/26
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§ion=6http://en.wikipedia.org/w/index.php?title=DC_motor&action=edit§ion=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§ion=7http://en.wikipedia.org/w/index.php?title=DC_motor&action=edit§ion=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§ion=6http://en.wikipedia.org/wiki/DC_motor#cite_note-2http://en.wikipedia.org/w/index.php?title=DC_motor&action=edit§ion=7http://en.wikipedia.org/wiki/DC_motor#cite_note-3 -
8/3/2019 Documentation....to Be Done
19/26
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
-
8/3/2019 Documentation....to Be Done
20/26
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.
-
8/3/2019 Documentation....to Be Done
21/26
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
-
8/3/2019 Documentation....to Be Done
22/26
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.
-
8/3/2019 Documentation....to Be Done
23/26
APPLICATIONS:
-
8/3/2019 Documentation....to Be Done
24/26
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/ -
8/3/2019 Documentation....to Be Done
25/26
-
8/3/2019 Documentation....to Be Done
26/26
p