speed control of dc motor by 555 timer ic

8/16/2019 Speed Control of DC motor by 555 timer IC

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ADAMAS INSTITIUTE OF

TECHNOLOGY

SPEED CONTROL OF DC MOTOR USING555TIMER IC

MADE BY

Suvam Sinha Anas Md. Seraj

Saikat Paul Gunjan Kumar

Akash Sutradhar Sk. Md. Washim Akram

Gourab Bhattacharya Arif Md. Khan

Jakir Mondal Md. Riazul

UNDER THE GUIDENCE OF:

ASST. PROF.: Madhushrota Bandopadhyay


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Declaration

I certify that

A. The work contained in this report is original and has been done by meunder the guidance of my supervisors.B. 1 have followed the guidelines provided by the Institute in preparing thereportC. I have conformed to the norms and guidelines given in the Ethical Codeof Conduct of the Institute.D. Whenever I have used materials (data, theoretical analysis, figures, andtext) from other sources. I have given due credit to them by citing them inthe text of the report and giving their details in the references. Further, I havetaken permission from the copyright owners of the sources, whenevernecessary.

Signature of the Student


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Acknowledgement

This project would not have been possible without the support and love of a number of

incredibly special people.

My Family, friends and specially my Department guided me very well. They are morehelp to me. Thank you all.

I want to thank all the team members of my group in the project

Finally. I would like to thank my faculties, Madhushrota Bandopadhyay and Gopal

Chandra Dey for helping me to do successfully this project.


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Abstract

There are several motor control circuits and this is one of the commonly used

motor control circuit and it was done by employing a simple NE555IC. The

timer IC here was used to generate PWM waves so that the speed of the motor

can be adjusted accordingly. PWM is nothing but Pulse Width modulation, a

modulation technique in which the width of the output pulse was varied with

respect to the amplitude of the input signal.


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Table of Contents

Topic Page No.

1. Introduction 1

2. Components 2

2.1 555Timer IC 2

2.2 Resistor 5

2.3 Diode 6

2.4 Resistance Pot 7

2.5 Capacitor 8

2.6 D.C. Motor 9

2.7 Veroboard 10

2.8 Solder 11

2.9 Soldering iron 12

2.10 Switch mode power supply 13

3.

Working of dc motor speed control circuit 144. Future Modification 15

5. Conclusion 16

6. Reference 17


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1. INTRDUCTION

The basic principle of the DC motor is a device which converts DC energy

into mechanical energy. When the current carrying armature is connected tothe supply end though commentator segment, brushes are placed within the

North South Poles of permanent or electromagnets. By using these

electromagnets operating principle is depends on the Fleming’s left hand rule

to determine the direction of the force acting on the armature conductors of

the DC motor.

Speed Control of Shunt Motors

Flux control method

Armature and Rheostatic control method

Voltage control method

1.

Multiple voltage control

2. Ward Leonard system

Speed Control of Series Motors

Flux control method

1.

Field diverter

2.

Armature diverter

3. Trapped field control

4. Paralleling field coils

Variable Resistance in series with motor

Series -parallel control method


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2. COMPONENTS

2.1 555 timer IC

The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse

generation, and oscillator applications. The 555 can be used to provide time

delays, as an oscillator, and as a flip-flop element. Derivatives provide up to four

timing circuits in one package.

Introduced in 1971 by American company Signetics, the 555 is still in widespread

use due to its low price, ease of use, and stability. It is now made by many

companies in the original bipolar and also in low-power CMOS types. As of 2003,it was estimated that 1 billion units are manufactured every year.

https://en.wikipedia.org/wiki/Integrated_circuithttps://en.wikipedia.org/wiki/Timerhttps://en.wikipedia.org/wiki/Electronic_oscillatorhttps://en.wikipedia.org/wiki/Oscillatorhttps://en.wikipedia.org/wiki/Flip-flop_elementhttps://en.wikipedia.org/wiki/United_Stateshttps://en.wikipedia.org/wiki/Signeticshttps://en.wikipedia.org/wiki/Bipolar_junction_transistorhttps://en.wikipedia.org/wiki/CMOShttps://en.wikipedia.org/wiki/CMOShttps://en.wikipedia.org/wiki/Bipolar_junction_transistorhttps://en.wikipedia.org/wiki/Signeticshttps://en.wikipedia.org/wiki/United_Stateshttps://en.wikipedia.org/wiki/Flip-flop_elementhttps://en.wikipedia.org/wiki/Oscillatorhttps://en.wikipedia.org/wiki/Electronic_oscillatorhttps://en.wikipedia.org/wiki/Timerhttps://en.wikipedia.org/wiki/Integrated_circuit


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Design

The IC was designed in 1971 by Hans R. Camenzind under contract to Signetics,

which was later acquired by Dutch company Philips Semiconductors (now NXP).

Depending on the manufacturer, the standard 555 package includes 25 transistors, 2 diodes and 15 resistors on a silicon chip installed in an 8-pin mini dual-in-line

package (DIP-8). Variants available include the 556 (a 14-pin DIP combining two

555s on one chip), and the two 558 & 559s (both a 16-pin DIP combining four

slightly modified 555s with DIS & THR connected internally, and TR is falling

edge sensitive instead of level sensitive).

The NE555 parts were commercial temperature range, 0 °C to +70 °C, and

the SE555 part number designated the military temperature range, −55 °C to +125

°C. These were available in both high-reliability metal can (T package) andinexpensive epoxy plastic (V package) packages. Thus the full part numbers were

NE555V, NE555T, SE555V, and SE555T. It has been hypothesized that the 555

got its name from the three 5 kΩ resistors used within, but Hans Camenzind has

stated that the number was arbitrary.[1]

Low-power versions of the 555 are also available, such as the 7555 and CMOS

TLC555. The 7555 is designed to cause less supply noise than the classic 555 and

the manufacturer claims that it usually does not require a "control" capacitor and

in many cases does not require a decoupling capacitor on the power supply. Those

parts should generally be included, however, because noise produced by the timer

or variation in power supply voltage might interfere with other parts of a circuit

or influence its threshold voltages.

Pins

Pinout diagram

https://en.wikipedia.org/wiki/Hans_R._Camenzindhttps://en.wikipedia.org/wiki/Signeticshttps://en.wikipedia.org/wiki/Netherlandshttps://en.wikipedia.org/wiki/Philips_Semiconductorshttps://en.wikipedia.org/wiki/NXPhttps://en.wikipedia.org/wiki/Transistorhttps://en.wikipedia.org/wiki/Diodehttps://en.wikipedia.org/wiki/Resistorhttps://en.wikipedia.org/wiki/Siliconhttps://en.wikipedia.org/wiki/DIP-8https://en.wikipedia.org/wiki/Ohmhttps://en.wikipedia.org/wiki/Ohmhttps://en.wikipedia.org/wiki/Ohmhttps://en.wikipedia.org/wiki/555_timer_IC#cite_note-semiconductormuseum.com-1https://en.wikipedia.org/wiki/555_timer_IC#cite_note-semiconductormuseum.com-1https://en.wikipedia.org/wiki/555_timer_IC#cite_note-semiconductormuseum.com-1https://en.wikipedia.org/wiki/Decoupling_capacitorhttps://en.wikipedia.org/wiki/File:555_Pinout.svghttps://en.wikipedia.org/wiki/Decoupling_capacitorhttps://en.wikipedia.org/wiki/555_timer_IC#cite_note-semiconductormuseum.com-1https://en.wikipedia.org/wiki/Ohmhttps://en.wikipedia.org/wiki/DIP-8https://en.wikipedia.org/wiki/Siliconhttps://en.wikipedia.org/wiki/Resistorhttps://en.wikipedia.org/wiki/Diodehttps://en.wikipedia.org/wiki/Transistorhttps://en.wikipedia.org/wiki/NXPhttps://en.wikipedia.org/wiki/Philips_Semiconductorshttps://en.wikipedia.org/wiki/Netherlandshttps://en.wikipedia.org/wiki/Signeticshttps://en.wikipedia.org/wiki/Hans_R._Camenzind


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The connection of the pins for a DIP package is as follows:

Pin Name Purpose

1 GND Ground reference voltage, low level (0 V)

2 TRIG

The OUT pin goes high and a timing interval starts when this

input falls below 1/2 of CTRL voltage (which is typically

1/3 VCC, CTRL being 2/3 VCC by default if CTRL is left open).

3 OUT This output is driven to approximately 1.7 V below +VCC, or toGND.

4 RESET

A timing interval may be reset by driving this input to GND, but

the timing does not begin again until RESET rises above

approximately 0.7 volts. Overrides TRIG which overrides THR.

5 CTRL Provides "control" access to the internal voltage divider (bydefault, 2/3 VCC).

6 THR

The timing (OUT high) interval ends when the voltage at THR

("threshold") is greater than that at CTRL (2/3 VCC if CTRL is

open).

7 DISOpen collector output which may discharge a capacitor between

intervals. In phase with output.

8 VCC Positive supply voltage, which is usually between 3 and 15 V

depending on the variation.

https://en.wikipedia.org/wiki/IC_power-supply_pinhttps://en.wikipedia.org/wiki/IC_power-supply_pinhttps://en.wikipedia.org/wiki/IC_power-supply_pinhttps://en.wikipedia.org/wiki/Open_collectorhttps://en.wikipedia.org/wiki/Open_collectorhttps://en.wikipedia.org/wiki/IC_power-supply_pin


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2.2 Resistor

A resistor is a passive two-terminal electrical component that

implements electrical resistance as a circuit element. Resistors may be used to

reduce current flow, and, at the same time, may act to lower voltage levelswithin circuits. In electronic circuits, resistors are used to limit current flow, to

adjust signal levels, bias active elements, and terminate transmission

lines among other uses. High-power resistors, that can dissipate many watts of

electrical power as heat, may be used as part of motor controls, in power

distribution systems, or as test loads for generators. Fixed resistors have

resistances that only change slightly with temperature, time or operating voltage.

Variable resistors can be used to adjust circuit elements (such as a volume

control or a lamp dimmer), or as sensing devices for heat, light, humidity, force,

or chemical activity.

Resistors are common elements of electrical networks and electronic circuits and

are ubiquitous in electronic equipment. Practical resistors as discrete components

can be composed of various compounds and forms. Resistors are also

implemented within integrated circuits.

The electrical function of a resistor is specified by its resistance: common

commercial resistors are manufactured over a range of more than nine orders of

magnitude. The nominal value of the resistance will fall within a manufacturing

tolerance.

https://en.wikipedia.org/wiki/Passivity_(engineering)https://en.wikipedia.org/wiki/Terminal_(electronics)https://en.wikipedia.org/wiki/Electronic_componenthttps://en.wikipedia.org/wiki/Electrical_resistancehttps://en.wikipedia.org/wiki/Biasinghttps://en.wikipedia.org/wiki/Transmission_linehttps://en.wikipedia.org/wiki/Transmission_linehttps://en.wikipedia.org/wiki/Watthttps://en.wikipedia.org/wiki/Electric_generatorhttps://en.wikipedia.org/wiki/Electrical_networkhttps://en.wikipedia.org/wiki/Electronic_circuithttps://en.wikipedia.org/wiki/Electronicshttps://en.wikipedia.org/wiki/Integrated_circuitshttps://en.wikipedia.org/wiki/Orders_of_magnitudehttps://en.wikipedia.org/wiki/Orders_of_magnitudehttps://en.wikipedia.org/wiki/Engineering_tolerance#Electrical_component_tolerancehttps://en.wikipedia.org/wiki/Engineering_tolerance#Electrical_component_tolerancehttps://en.wikipedia.org/wiki/Engineering_tolerance#Electrical_component_tolerancehttps://en.wikipedia.org/wiki/Engineering_tolerance#Electrical_component_tolerancehttps://en.wikipedia.org/wiki/Orders_of_magnitudehttps://en.wikipedia.org/wiki/Orders_of_magnitudehttps://en.wikipedia.org/wiki/Integrated_circuitshttps://en.wikipedia.org/wiki/Electronicshttps://en.wikipedia.org/wiki/Electronic_circuithttps://en.wikipedia.org/wiki/Electrical_networkhttps://en.wikipedia.org/wiki/Electric_generatorhttps://en.wikipedia.org/wiki/Watthttps://en.wikipedia.org/wiki/Transmission_linehttps://en.wikipedia.org/wiki/Transmission_linehttps://en.wikipedia.org/wiki/Biasinghttps://en.wikipedia.org/wiki/Electrical_resistancehttps://en.wikipedia.org/wiki/Electronic_componenthttps://en.wikipedia.org/wiki/Terminal_(electronics)https://en.wikipedia.org/wiki/Passivity_(engineering)


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2.3 Diode

The most common function of a diode is to allow an electric current to pass in one

direction (called the diode's forward direction), while blocking current in the oppositedirection (the reverse direction). Thus, the diode can be viewed as an electronic version

of a check valve. This unidirectional behaviour is called rectification, and is used to

convert alternating current to direct current, including extraction of modulation from

radio signals in radio receivers — these diodes are forms of rectifiers.

However, diodes can have more complicated behaviour than this simple on – off action,

because of their nonlinear current-voltage characteristics. Semiconductor diodes begin

conducting electricity only if a certain threshold voltage or cut-in voltage is present in

the forward direction (a state in which the diode is said to be forward-biased). Thevoltage drop across a forward-biased diode varies only a little with the current, and is a

function of temperature; this effect can be used as a temperature sensor or as a voltage

reference.

A semiconductor diode's current – voltage characteristic can be tailored by selecting

the semiconductor materials and the doping impurities introduced into the materials

during manufacture. These techniques are used to create special-purpose diodes that

perform many different functions. For example, diodes are used to regulate voltage

(Zener diodes), to protect circuits from high voltage surges (avalanche diodes), to

electronically tune radio and TV receivers (varactor diodes), to generate radio-frequency oscillations (tunnel diodes, Gunn diodes, IMPATT diodes), and to produce

light (light-emitting diodes). Tunnel, Gunn and IMPATT diodes exhibit negative

resistance, which is useful in microwave and switching circuits.

Diodes, both vacuum and semiconductor, can be used as shot-noise generators.

https://en.wikipedia.org/wiki/Check_valvehttps://en.wikipedia.org/wiki/Rectification_(electricity)https://en.wikipedia.org/wiki/Alternating_currenthttps://en.wikipedia.org/wiki/Direct_currenthttps://en.wikipedia.org/wiki/Modulationhttps://en.wikipedia.org/wiki/Rectifierhttps://en.wikipedia.org/wiki/Linear_circuithttps://en.wikipedia.org/wiki/P%E2%80%93n_junction#Forward_biashttps://en.wikipedia.org/wiki/Diode#Temperature_measurementshttps://en.wikipedia.org/wiki/Voltage_referencehttps://en.wikipedia.org/wiki/Voltage_referencehttps://en.wikipedia.org/wiki/Semiconductor_materialshttps://en.wikipedia.org/wiki/Doping_(semiconductor)https://en.wikipedia.org/wiki/Zener_diodehttps://en.wikipedia.org/wiki/Avalanche_diodehttps://en.wikipedia.org/wiki/Varactor_diodehttps://en.wikipedia.org/wiki/Radio_frequencyhttps://en.wikipedia.org/wiki/Radio_frequencyhttps://en.wikipedia.org/wiki/Oscillationhttps://en.wikipedia.org/wiki/Tunnel_diodehttps://en.wikipedia.org/wiki/Gunn_diodehttps://en.wikipedia.org/wiki/IMPATT_diodehttps://en.wikipedia.org/wiki/Light-emitting_diodehttps://en.wikipedia.org/wiki/Negative_resistancehttps://en.wikipedia.org/wiki/Negative_resistancehttps://en.wikipedia.org/wiki/Microwavehttps://en.wikipedia.org/wiki/Noise_generator#Shot_noise_generatorshttps://en.wikipedia.org/wiki/Noise_generator#Shot_noise_generatorshttps://en.wikipedia.org/wiki/Microwavehttps://en.wikipedia.org/wiki/Negative_resistancehttps://en.wikipedia.org/wiki/Negative_resistancehttps://en.wikipedia.org/wiki/Light-emitting_diodehttps://en.wikipedia.org/wiki/IMPATT_diodehttps://en.wikipedia.org/wiki/Gunn_diodehttps://en.wikipedia.org/wiki/Tunnel_diodehttps://en.wikipedia.org/wiki/Oscillationhttps://en.wikipedia.org/wiki/Radio_frequencyhttps://en.wikipedia.org/wiki/Radio_frequencyhttps://en.wikipedia.org/wiki/Varactor_diodehttps://en.wikipedia.org/wiki/Avalanche_diodehttps://en.wikipedia.org/wiki/Zener_diodehttps://en.wikipedia.org/wiki/Doping_(semiconductor)https://en.wikipedia.org/wiki/Semiconductor_materialshttps://en.wikipedia.org/wiki/Voltage_referencehttps://en.wikipedia.org/wiki/Voltage_referencehttps://en.wikipedia.org/wiki/Diode#Temperature_measurementshttps://en.wikipedia.org/wiki/P%E2%80%93n_junction#Forward_biashttps://en.wikipedia.org/wiki/Linear_circuithttps://en.wikipedia.org/wiki/Rectifierhttps://en.wikipedia.org/wiki/Modulationhttps://en.wikipedia.org/wiki/Direct_currenthttps://en.wikipedia.org/wiki/Alternating_currenthttps://en.wikipedia.org/wiki/Rectification_(electricity)https://en.wikipedia.org/wiki/Check_valve


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2.4 Resistance Pot

A potentiometer, informally a pot, is a three-terminal resistor with a sliding or rotating contact

that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper,it acts as a variable resistor or rheostat.

The measuring instrument called a potentiometer is essentially a voltage divider used for

measuring electric potential (voltage); the component is an implementation of the same

principle, hence its name.

Potentiometers are commonly used to control electrical devices such as volume controls on

audio equipment. Potentiometers operated by a mechanism can be used as position transducers,

for example, in a joystick. Potentiometers are rarely used to directly control significant power

(more than a watt), since the power dissipated in the potentiometer would be comparable to the power in the controlled load.

https://en.wikipedia.org/wiki/Terminal_(electronics)https://en.wikipedia.org/wiki/Resistorhttps://en.wikipedia.org/wiki/Voltage_dividerhttps://en.wikipedia.org/wiki/Potentiometer_(measuring_instrument)https://en.wikipedia.org/wiki/Electric_potentialhttps://en.wikipedia.org/wiki/Transducerhttps://en.wikipedia.org/wiki/Joystickhttps://en.wikipedia.org/wiki/Watthttps://en.wikipedia.org/wiki/Watthttps://en.wikipedia.org/wiki/Joystickhttps://en.wikipedia.org/wiki/Transducerhttps://en.wikipedia.org/wiki/Electric_potentialhttps://en.wikipedia.org/wiki/Potentiometer_(measuring_instrument)https://en.wikipedia.org/wiki/Voltage_dividerhttps://en.wikipedia.org/wiki/Resistorhttps://en.wikipedia.org/wiki/Terminal_(electronics)


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2.5 Capacitor

A capacitor (originally known as a condenser) is a passive two-terminal electrical

component used to store electrical energy temporarily in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical

conductors (plates) separated by a dielectric (i.e. an insulator that can store energy by

becoming polarized). The conductors can be thin films, foils or sintered beads of metal

or conductive electrolyte, etc. The non-conducting dielectric acts to increase the

capacitor's charge capacity. Materials commonly used as dielectrics

include glass, ceramic, plastic film, air, vacuum, paper, mica, and oxide layers.

Capacitors are widely used as parts of electrical circuits in many common electrical

devices. Unlike a resistor, an ideal capacitor does not dissipate energy. Instead, a

capacitor stores energy in the form of an electrostatic field between its plates.

An ideal capacitor is characterized by a single constant value, its capacitance.

Capacitance is defined as the ratio of the electric charge Q on each conductor to the

potential difference V between them. The SI unit of capacitance is the farad (F), which

is equal to one coulomb per volt (1 C/V). Typical capacitance values range from about

1 pF (10−12 F) to about 1 mF (10−3 F).

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2.6 DC motor

A DC motor is any of a class of electrical machines that converts direct current electrical power

into mechanical power. The most common types rely on the forces produced by magnetic

fields. Nearly all types of DC motors have some internal mechanism, either electromechanicalor electronic, to periodically change the direction of current flow in part of the motor. Most

types produce rotary motion; a linear motor directly produces force and motion in a straight

line.

DC motors were the first type widely used, since they could be powered from existing direct-

current lighting power distribution systems. A DC motor's speed can be controlled over a wide

range, using either a variable supply voltage or by changing the strength of current in its field

windings. Small DC motors are used in tools, toys, and appliances. The universal motor can

operate on direct current but is a lightweight motor used for portable power tools and

appliances. Larger DC motors are used in propulsion of electric vehicles, elevator and hoists,

or in drives for steel rolling mills. The advent of power electronics has made replacement of

DC motors with AC motors possible in many applications.

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2.7 Veroboard

Veroboard is a brand of stripboard, a pre-formed circuit board material of copper strips on an insulating board which

was originated and developed in the early 1960s by the Electronics Department of Vero Precision Engineering

Ltd (VPE). It was introduced as a general-purpose material for use in constructing electronic circuits - differing from

purpose-designed printed circuit boards (PCBs) in that a variety of electronics circuits may be constructed using a

standard wiring board.

The first single-size Veroboard product was the forerunner of the numerous types of prototype wiring board which,

with world-wide use over five decades, have become known as Stripboard.

The generic terms 'veroboard' and 'stripboard' are now taken to be synonymous.

https://en.wikipedia.org/wiki/Stripboardhttps://en.wikipedia.org/wiki/Circuit_boardhttps://en.wikipedia.org/wiki/Electronicshttps://en.wikipedia.org/wiki/Vero_Precision_Engineering_Ltdhttps://en.wikipedia.org/wiki/Vero_Precision_Engineering_Ltdhttps://en.wikipedia.org/wiki/Electronic_circuitshttps://en.wikipedia.org/wiki/Printed_circuit_boardshttps://en.wikipedia.org/wiki/Prototypehttps://en.wikipedia.org/wiki/Prototypehttps://en.wikipedia.org/wiki/Printed_circuit_boardshttps://en.wikipedia.org/wiki/Electronic_circuitshttps://en.wikipedia.org/wiki/Vero_Precision_Engineering_Ltdhttps://en.wikipedia.org/wiki/Vero_Precision_Engineering_Ltdhttps://en.wikipedia.org/wiki/Electronicshttps://en.wikipedia.org/wiki/Circuit_boardhttps://en.wikipedia.org/wiki/Stripboard


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2.8 Solder

Solder is a fusible metal alloy used to create a permanent bond between metal

workpieces. Solder must be melted in order to adhere to and connect the pieces together,

so a suitable alloy for use as solder will have a lower melting point than the pieces it isintended to join. Whenever possible, the solder should also be resistant to oxidative and

corrosive effects that would degrade the joint over time. Solders intended for use in

making electrical connections between electronic components also usually have

favourable electrical characteristics.

Soft solder typically has a melting point range of 90 to 450 °C (190 to 840 °F), and is

commonly used in electronics, plumbing, and sheet metal work. Manual soldering uses

a soldering iron or soldering gun. Alloys that melt between 180 and 190 °C (360 and

370 °F) are the most commonly used. Soldering performed using alloys with a melting

point above 450 °C (840 °F) is called 'hard soldering', 'silver soldering', or brazing.

In specific proportions, some alloys can become eutectic — that is, their melting point

is the same as their freezing point. Non-eutectic alloys have markedly

different solidus and liquids temperatures, and within that range they exist as a paste of

solid particles in a melt of the lower-melting phase. In electrical work, if the joint is

disturbed in the pasty state before it has solidified totally, a poor electrical connection

may result; use of eutectic solder reduces this problem. The pasty state of a non-eutectic

solder can be exploited in plumbing as it allows molding of the solder during cooling,

e.g. for ensuring watertight joint of pipes, resulting in a so-called 'wiped joint'.

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2.10 Switched-mode power supply A switched-mode power is an electronic power supply that incorporates a switching regulator

to convert electrical power efficiently. Like other power supplies, an SMPS transfers power

from a source, like mains power, to a load, such as a personal computer, while converting

voltage and current characteristics. Unlike a linear power supply, the pass transistor of a

switching-mode supply continually switches between low-dissipation, full-on and full-off

states, and spends very little time in the high dissipation transitions, which minimizes wasted

energy. Ideally, a switched-mode power supply dissipates no power. Voltage regulation is

achieved by varying the ratio of on-to-off time. In contrast, a linear power supply regulates theoutput voltage by continually dissipating power in the pass transistor. This higher power

conversion efficiency is an important advantage of a switched-mode power supply. Switched-

mode power supplies may also be substantially smaller and lighter than a linear supply due to

the smaller transformer size and weight.

https://en.wikipedia.org/wiki/Power_supplyhttps://en.wikipedia.org/wiki/Electrical_power_conversionhttps://en.wikipedia.org/wiki/Mains_electricityhttps://en.wikipedia.org/wiki/Personal_computerhttps://en.wikipedia.org/wiki/Voltagehttps://en.wikipedia.org/wiki/Electric_currenthttps://en.wikipedia.org/wiki/Linear_power_supplyhttps://en.wikipedia.org/wiki/Dissipationhttps://en.wikipedia.org/wiki/Voltage_regulatorhttps://en.wikipedia.org/wiki/Transistorhttps://en.wikipedia.org/wiki/Transistorhttps://en.wikipedia.org/wiki/Voltage_regulatorhttps://en.wikipedia.org/wiki/Dissipationhttps://en.wikipedia.org/wiki/Linear_power_supplyhttps://en.wikipedia.org/wiki/Electric_currenthttps://en.wikipedia.org/wiki/Voltagehttps://en.wikipedia.org/wiki/Personal_computerhttps://en.wikipedia.org/wiki/Mains_electricityhttps://en.wikipedia.org/wiki/Electrical_power_conversionhttps://en.wikipedia.org/wiki/Power_supply


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3. WORKING OF DC MOTOR SPEED CONTROL CIRCUIT:

The above IC 555 was wired as an Astable multivibrator which produces a series of

square wave pulses as output. In order to make the IC 555 to produce PWM output

signal modification in the astable circuit was needed. Generally the output frequency

of the Astable multivibrator depends on the Resistors and Capacitors attached to it.

The duty cycle of the output was governed by the Variable resistor R1 connected

between the pin 6 and pin 7.This resistor holds the key for generating the PWM waves

from the IC output so by varying the resistance in the R1 the output width of the pulse

can be varied as desired resulting in the generation of PWM waves.

The next stage was very simple it helps in driving the DC motor. The output of the IC1

is coupled to the base of the transistor Q1 which drives the motor according to the

incoming signal from the output of the 555 IC. When the duty cycle of the PWM signal

is high then the speed of the motor will be high and vice versa. The V indicates the

voltage required for the motor and it should be selected based on the motor you are about

to control with the IC. The switch was used here in order to change the direction of the

running motor, when the voltage applied in the opposite direction of the motor it will

result in running of the motor in opposite direction. Thus the R1 can be used as a switch

in order to control the motor by this way the PWM generation and DC motor control

can be done with simple 555 IC.


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4.

FUTURE MODIFICATIONS:

GOAL “To highlight possible modifications that can be made in the project for

improving performance”.

Following are the possible future modifications in our project work.

1. Use of microcontroller/micro-processor for closed loop operation.

2.

Use of MOSFET or IGBT.


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5.

CONCLUSION:

This application note describes how to control DC motor using 555 timer.Overall, there may be better way to control DC motor with precise timing and

position for example microcontroller, unfortunately, some of them are tedious,

some of them are not applicable in our project. The reason I pick 555 timer is

that it is non-programmable and still could provide accurate timing and position.

Also, in our project particularly, we do not really care where the flipper going to

stop as long as it is not above 180 degree, so the only thing that I pay more

attention is timing control. However, there are still some issues to bear in mind

as the modifications advance. Changes will make to this document accordingly.


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6.

References:

www.google.com

www.wikipedia.com

www.instructables.com

www.egr.msu.edu

www.circuitdigest.com

www.circuitstoday.com
http://www.google.com/http://www.google.com/http://www.wikipedia.com/http://www.wikipedia.com/http://www.instructables.com/http://www.instructables.com/http://www.egr.msu.edu/http://www.egr.msu.edu/http://www.circuitdigest.com/http://www.circuitdigest.com/http://www.circuitstoday.com/http://www.circuitstoday.com/http://www.circuitstoday.com/http://www.circuitdigest.com/http://www.egr.msu.edu/http://www.instructables.com/http://www.wikipedia.com/http://www.google.com/

speed control of dc motor by 555 timer ic

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