ABSTRACT
AFFILIATED TO
A PROJECT REPORT ON
The construction of ali ght dimmer circuit that utilizes the current-regulating egulating properties of
ACKNOWLEDGEMENT
GUJARATTECHNOLOGICALUNIVERSITY(GTU)
at riac. Prior to beingtriggered,the triac provides abarrier in thecircuit, preventingcurrent flow
“LIGHT DIMMER BY USING TRIAC AND DIAC”
Names PATANWADIA DHAVAL M.
froma 70VAC sourcethrough thelight bulb. Duringthis timevoltage across a capacitor within
GOVERNMENT POLYTECHNIC , (RAJPIPLA RAJPIPLA))
SUBMITTED BY, Enroll No:
(UNDER M.H.R.D.GUJARATTECHNOLOGICALUNIVERSITY)
159730309028
DEPARTMENT OF ELECTRICAL ENGINEERING
SEWALE BHAVYA V.
159730309047
SHETH SAGAR M.
159730309048
VALAND PIYUSH M.
159730309056
TheCompletion of any task is incomplete withoutmentioning thepeople whoseconstant guidance and solution for the minoror major problems related to our task.
in the circuit builds up untilit exceeds the breakover eakover voltage of a diac. Once the breakover voltage is exceeded, the diac“ fires” the triac into aconducting state and current flows through
We give our gratitudeto our project guide, in charge of HOD Shree M.B.TADVI of
thelight bulb. Theamount of voltage tage seen over thelight bulb is determined by the firingangle of
electrical department forhis orhis constant support and guidanceand encouragement.Wea lso giveour
thet riacwhich is set by the RC timeconstant of thecircuit. This process then repeats every half
gratitudeto our principle Shree K.D.PATEL for encouragement and giving us moralsupport and
cycle. Finally, it can beseen that t his switchingintroduces high orderharmonics into the system.
our faculties MS. KRISHNAB. CHAUHAN too solve our queries related to task. Finally,we express our gratitudeto all other members who areinvolved either directly or indirectly forthe completion of this project.
GUIDED BY :- Ms KRISHNA B. CHAUHAN
CERTIFICATE
DEPARTMENT OF ELECTRICAL ENGINEERING
This is to that the following students (5 th SEM) have satisfactorily completed his project work entitled as “LIGHTDIMMERBY USING TRIACAND DIAC”for the term ending in OCT-2017.
IN GOVERNMENT POLYTECHNIC , RAJPIPLA
Names
Enroll No:
PATANWADIA DHAVAL M.
159730309028
SEWALE BHAVYA V.
159730309047
SHETHS AGAR M.
159730309048
VALAND PIYUSHM.
159730309056
DATE (Project Guide )
(Head of Department )
Ms KRISHNA B CHAUHAN 1
2
CHAPTERNO :1
INDEX NO
2
PAGE NO.
such as a diac and a triac,p ower flow is regulated to a light bulb by intermittently applyinga
SIGN
70V AC source ce across theload duringeach half cycle. The intensity of thelight is determined by the proportion of thesine wavet hat is applied across theload. This document contains the
INTRODUCTION OF PROJECT
then you have to replace with low watt ratingbulb. But, if there is not needed to change the brightness ofthe light fromthe same light source,hereis the simplelight dimmer circuit project, ect, which is used to controlt he brightness of the light according ng to our requirement. This light dimmer circuit cuit is used to control the voltage which gets to the light. This circuit has been possiblefor many decades by usingvariabletransformers and resistors
circuit operation, testingresults, and theobservations that weremade duringthe experiment.
BLOCKDIAGRAM
BLOCKDIAGRAM
rating. If youneed morelight, then you have to usehigh watt bulb and if you need low light,
The construction, operation, and testingof a light dimmer circuit. Using simpledevices
1.
CHAPTER NO 2.
The light sources such as tube light or bulbs blink accordingt o their particular watt
NAME
4
1.2 PRI NCIPLE OPERATIONS
1.1INTRODUCTION
SR.
3
The controlcircuitry consists of thefollowing :
3
CIRCUITDIAGRAM
1. Triggering circuit
4.
COMPONENT & ITS ESTIMATED COST
2. Triac circuit and
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TECHNICAL DISCRIPTIONOF COMPONENT
6
PROJECTPLANNING
7
REFERENCE
3. Power supply circuit. The power supply circuit willp rovideDC supply 5v and 12v to the electronicwhich requirethe biasingvoltage. The triggering circuit will ll generatethe pulses and are given to triac as gatepulses for triggeringpurpose. And finally triac circuit acts as intermediate part between supply and induction motor.
Figure
Thereforeapplied voltagefromt hesupply to induction motor and thereby lights arecontrolled.
In this method of control we are using an intermediate ate part called AC cycloconverter ter between theAC supply and light. Therefore supply voltage is controlled by controllingt ollingt hegate pulses to the cycloconverter. And thereby torque is also controlled and thus the controlof the lightintensity.
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6
7
WORKING
CHAPTER NO: 3
CHAPTER NO: 4
CHAPTER NO.5
4.1COMPONENTLIST
3.1 CIRCUITDIA GRAM& ITS WORKING LIGHT DIMMER CIRCUIT USINGTRIAC
cycle, then the light bulb will appear with less intensity when it gets thefull AC voltage.Because
kilo ohms and VR2=200 kilo ohms, capacitors C1, C2 and C3=0.33 uF/400V, TRIAC is BT136
it gets the low powerto heatt hefilament. Thesel ight dimmers use thebrightness knob to control
and DIAC is ER900.
at what point each cycle to switch the light ON and OFF.
3.1.1
2. DIAC
applied to theli ghts being controlled. For instance,if the voltage is applied to half of theAC
resistors R1=68 kilo ohms,R2=280 kilo ohms and R3=10 kilo ohms, variable resistors VR1=100
DIFFERENTCOMPONENTIN DETAIL
1. TRIAC
Modern light dimmers work by changing the duty cycleof the AC voltage which is
This light dimmer circuit is built with various electrical and electroniccomponents like
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TRIAC
3. TRANSFORMER
As mentioned above, triac is a three terminal, four layer bilateral semiconductor
4. ZENER DIODE
device. It incorporates two SCRs connected in inverse parallel w ith a common gate
5. SCR
terminal in a single chip device. The arrangement of the triac is shown in figure. As
6. RECTIFIER
seen, it has s ix doped regions. The gate terminal G makes ohmic contacts with both the
7. CAPACITOR
Typical light dimmers are built with thyristors and thefixed time when thet hyristor is
N and P materials. This permits trigger pulse of either polarity to start conduction.
activated virtualto the zero crossings of theAC power is used to determine the levelof power.
8. RESISTOR
When thethyristor activates then it keeps directing untilthe current passingthrough when it goes
9. LIGHT EMITTING DIODE (LED)
Electrical equivalent circuit and schematic symbol are shown in figure.1 and figure 2 respectively. Since the t riac is a bilateral d evice, the term “ anode” and “cathode”has no
to zero. Thephase can be changed when the TRIAC is activated, you changethe duty cycleand
meaning, and therefore, terminals are designated as main terminal1. (MT1), main terminal2
thus thebrightnessofthe light.
(MT2) and gate G. To avoid confusion, it has become common practice to specify all voltages and currents using MT 1 as the reference.
Fig:3
The basiccircuit of light dimmer usingTRIAC is shown below and this circuit depends on phasecontrol. Thevariableresistor VR1 playsas a main controller oller in thelight dimmer circuit. Thecapacitor ‘C2’in the circuit below gets chargefromthe main supply. y. In the circuit, variable resistor VR1 and D1 DIAC areused to controlthe brightness of the lower level. To overcomethe interfaceproblem, R2 &C3 areused. Fig: 6
Here in this light dimmer circuit, without any change DIAC can be replaced by the BC148 transistor. When the transistor is used instead of DIAC, then thebase terminal of the
CHARACTERISTICS OF TRIAC
transistor not connected and remainingterminals like emitter and collector areconnected without thehelp of polarity. In this circuit, diodeis used as a DIAC.
Typical V-I characteristics of a triac are shown in figure. The triac has on and off state characteristics similar to SCR but now the characteristic is applicable to both
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10
positive and negative voltages. This is expected because triac consists of two SCR
MT2 is positive with respect to MTX in the first quadrant and it is negative in the third quad rant. As already said in previous blogposts , the gate t riggering may occur in any of the following four modes.
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the diac cannot bee xpected to maintain a low (on) voltagedrop untilits current falls below a 3.1.2
connected in parallel but opposite in directions.
11
DIAC
holdingcurrentlevel.
A diac is an important member of the thyristor family and is usually employed for triggering triacs. A
diac
is a
two-electrode bidirectional rectional
can be switched from off-state f-state to the on-state voltage. This
is
for
avalanche diodewhich
either polarity
just like a triac without gate terminal, as shown
of
the applied in figure. e. Its
equivalent circuit is a pair of inverted four layer diodes. Two schematic symbols are shown in figure. Again the terminal designations are arbitrary since thediac, liketriac, is also a bilateral device. Theswitching from off-state to
on-state is
achieved by simply
exceeding the avalanche break down voltage in either direction.
Fig:10 Transformer If
a load is connected to the secondary, an electric current will flow in the
secondary winding and electrical energy will be transferred from the primary circuit through the transformer to the load. In an ideal transformer, the induced voltage in the secondary winding ng [Vs] is in proportion to thep rimary voltage [Vp], and is given by the ratio of the number of thes econdary [Ns] to the number of turns in t he primary [Np] as follows: 3.1.4
Fig:7
3.1.3 Quadrant I Operatio
:
Quadrant II Operation : Quadrant IVOperation :
CHARACTERISTICS OF A DIAC
V MT2 Positive; VG1 Positive
Quadrant II Operation :
VMT21 Positive; VGl Negative V MT21 Negative;V Gl Negative Negative V MT21 Negative;VG1 Positive
Where V MT21 and VGl are the voltages of terminal MT2 and gate with respect to
Under specific fabrication conditions, tions, a diode may be created t hat will not be destroyed
TRANSFORMER
A transformer is a device that transfers electrical energy from one circuit to
Volt-amperecharacteristic of a diac is shown in figure. It resembles the English letterZ because
another through inductively coupled conductors the transformer’s coils. A varying
of thesymmetrical switchingcharacteristics for either polarity of theapplied voltage.
current in the first or primary winding creates a varying magnetic flux in the
The diac acts likean open-circuit untilit s switching ng or break overvoltageis exceeded. At that
transformer’s core
point the diac conducts until its current reduces toward zero (below t he level of the holding
winding. This varying magnetic field induces a varying electromotive force or
current of thedevice). The diac, becauseof its p eculiar construction, does not switch sharply ply into
“voltage” in the secondary winding. His effect is called mutual induction.
and thus a
if the breakdown voltage is exceeded, as long asthe current does not exceed a defined maximum (to prevent overheating). These devices are known as zener diode.
varying magnetic field through the secondary
a low voltagecondition at alow current levellike the SCR or triac. Instead, once it goes into
terminal MT1. The device, when starts conduction permits a very heavy amount of currentto flow through it. This large
ZENERDIODE
Fig:9
Fig:8
inrush of current must
be restricted
by employing external
conduction, the diac maintains an almost continuous negative resistance characteristic, that is voltagedecreases with the increasein current. This means that, unlike the SCR and the triac,
Fig: 11 ZENER DIODE
,
resistance, otherwise the device may get damaged. 13
14
15
16
3.1.5
SCR Filename: Directory:
3.1.8
dimmer circuit.docx C:\Users\ankur\Documents
TheTemplate: SCR [Silicon Controlled Rectifier] is a
three junction, four layer, and three
3.1.7
C:\Users\ankur\AppData\Roaming\Microsoft\Templates\Normal.do terminal type tm PNPN switching device. It consists of three electrodes – anode [A], cathode [K] andTitle: control electrode is called the gate [G]. It allows current to flow in only one Subject: direction so it device. Autho r: is known as unidirectional jay Keywords: Comments: C re a ti o nD a te : 1 0 -1 0 2 - 0 17 18 : 52 : 00 Change Number: 16 L a st Sa v ed O n: 1 0 -1 0 2 - 0 17 19 : 45 : 00 La st S av ed B y: D IT YA Total Editing Time: 45 Minute s Last Printed On: 11-10-2017 09:36:00 As ofLast Complete Printing NumberofPa ges: 26 NumberofWords: 2,995 (approx.) Number ofCharacters: 17,072 (approx.)
RESISTOR
A resistor is a t wo terminal electrical component that produces a voltage across its
CAPACITOR
A capacitor (formerly known as condenser) is a passive electronic component consisting of ap air of conductors separated by a dielectric (insulator). When a potential
terminals that is proportional to the e lectric current passing through it in accordance with Ohm’s law, V= IR
difference (voltage) exists across the conductors, an electric field is p resent in the dielectric. This field stores
energy and produced a mechanical force between the
conductors. The effect is greatest when there is a narrow separation between large areas LED
of conductors; hence capacitor conductors are often called plates. An ideal capacitor is
This effect is called electroluminescence and the color of t he light (corresponding to
characterized by a single constant value, capacitance, which is measured in faradays.
the energy of the photon) is determined by the energy gap of the se miconductor. An
This is the ratio of the electric charge on each conductors to the potential difference
LED is usually small in areas (less than 1mm2), and integrated optical components are
between t hem. In practice, the dielectric between the plates passes a small amount of
used to shapeits radiation pattern and assist in reflection.
leakage current. The conductors and leads introduce an equivalent series resistance and the dielectric has an
electric field strength limit resulting in a
LEDs present many advantages over incandescent light so urces including lower
breakdown voltage.
Capacitors are widely used in electronic circuits to block direct current while allowing alternating current to pass, to filter out
Fig: 12SCR 3.1.6
RECTIFIER
A rectifier is an
interference, to smooth the output of power
Resistors are elements of electrical networks and electronic circuits and ubiquitous
supplies, and for many other purposes. They are used in resonant circuits in radio
in most electronic equipment. Practical resistors can be made of various compounds and
frequency equipment to select particular frequencies from a signal with many frequencies.
films, as
well as resis tance wire (wire made of a high resistiv ity alloy, such as
nickel/chrome). The primary characteristics of a resistor are t he resistance, the tolerance,
electrical device that converts alternating current [AC], which
durability and greater reliability. However, they are relatively expensive and require more precise current and heat management than t raditional light sources. Current LED products for general lighting are more expensive to buy than fluorescent lamp sources of comparable output.
maximum working voltage and the power rating.
periodically reverses direction, to direct current [DC], current that flows in only one direction, a process known as
energy consumption, longer lifetime, improved robustness, smaller size, faster switching,
Fig 15RESISTOR
rectification. Rectifiers have many uses including as
3.1.9
LED
components of power supplies and as detectors of radio signals. Rectifiers may be made A LED is a semiconductor light source. LEDs are used as indicator lamps in many
of state diodes, vacuum tube diode, mercury arc values, and other components. The
devices, and are increasingly used for lighting. Early LEDs emitted low intensity red
output from the transformer is fed t o the rectifier. It converts AC into pulsating DC. The
light, but modern versions are available across t he visible, ultraviolet and infrared
rectifier may be a half wave or a full wave rectifier.
wavelengths, with very high brightness. The LED is based on the semiconductor diode. When a diode is forward biased (switched on), electrons are able to recombine with holes within the device, releasing energy in t he form of photons.
Fig: 14 CAPACITOR Fig: 13 BRIDGE RACTIFIER 17
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CHAPTER NO:4
CHAPTER NO: 6
N O .
1
P
A
R
T
I
C
U
L
A
R
S
M
O N
T H
. C O L L E C TI O N O F D A T A F R O M I N T E R N ET
3
.
4
. C O L L E C T
5
.
A N A L YS I S O F
6
.
P R E P A R AT I O N O F T H E R E P O R T W I T H P R E S E N T A T IO N
Low Initial Cost
Simple& Efficient Operation
Compact Size– cubic inches
Long Life– 30,000 to 50,000 hours
. F I N D I N G T H E T I T A L O F P R O J E C T A U GU ST 2 0 17
2
SEPTEMBER 2017
The invention is directed to an SCR circuit controlled universal motor which is equipped
Portability
Speed Control
with means for providing smooth speed controlat all speed settings that comprises a series-
No Demand Charge
wound statorfield in themotor and havingat least oneclosed conductor loop of wireencircling
the stator magnetic flux path. Preferably apair of separate closed conductor loops encirclet he magneticpath between thepoles although at least oneloop does improvethe speed control.The invention lies both in thestructure to providethe smooth speed controland in the method by which such controlis obtained.
No Exhaust Emissions
Withstand high temporary overloads
Automatic/RemoteStart& Control
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6.3 CONCLUSION:
6.2DISADVANTAGES
6.1 ADVANTAGES
4.1 PROJECT WORK DONE
19
PREPARATION OF INITIAL REPORT WITH PRESENTATION
C O M P O N E N T C I R CU I T
OCTOBER 2017
D IA G R A M
NOVEMBER 2017
21
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6.4 FUTURE SCOPE
BIBLIOGRAPHY WEBSITES
In electrical regulator by usingresistancethe outputvoltage is varied simultaneously the speed is varied.But to reduce the energy losses in the resistor , electronic regulator is introduced, which uses triac to vary theoutput voltage by varyingthef iringangle and avoids loss of energy
www.ebookbrowse.com
www.electronicsforyou.com
www.digitek.in
www.sridigitek.com
in resistor. This modelof speed controlof the fan (singlephase induction motor) is already existing technology. Our project(model) of speed controlof the fan is only an proto typefor the existing technology. The existingtechnology can beimproved by doingmodifications in the speedadjustment of thefan through controlling the triact riggeringpulses with micro-controller.And the work is been goingfor the moreefficient and automatic speed controlof the fan(single phaseinduction motor).
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