dyi: piezoelectric contact mic

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ACKNOWLEDGEMENT

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It is a privilege to have done my project in a company such as that of my fellow

classmate and project teammate, Tushar Mittal. I am grateful for his help and

support in completing this project.

I’d like to express my sincere gratitude to my project supervisor, Ms. Supriya

Sharma, assistant professor !!! department, M"IT# for her a$le guidance and

constant help throughout my project, without which the present work would not

have $een possi$le. I am also grateful towards %r &ajveeer Mittal '(%, !!!

department# for providing me the opportunity to work on this project.

I am also thankful to the faculty of the !!! department M"IT for the valua$le

advice, guidance, precious time and the support they have offered.

)ast $ut not the least I’d like to thank all of my fellow colleagues for giving me

their precious time, motivation and relevant information, without which I’d not

$e a$le to complete this project.

SI*+"T&! Students#

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CERTIFICATE

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This is to certify that the minor project report titled -TO DESIGN A BASIC

PREAMPLIFIER CIRCUIT BY USING A PIEZOELCTRIC BASED DISC

su$mitted in partial fulfilment of the re/uirement for the award of the degree of

0achelor (f Technology in Electrical and Electronics Engineering to Guru

Gobind Sing Indra!rasta "ni#ersit$ is a record of original work carried

out $y Karti% "!!al &'()*+,'+(*-. and Tusar Mittal &'(/+,'+(*-. under

my supervision and guidance and to the $est of my knowledge no part of this

report has $een su$mitted to any other university or institute for award of any

degree1diploma1certificate.

Dr 0Ra1#eer Mittal Ms0 Su!ri$a Sar2a

'(%, !!! %ept. M"IT# "ssistant 2rofessor, M"IT#

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DECLARATION

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3e, Karthik Uppal and T!har Mittal , !nrollment num$ers4"#$%&'"%( and

"#)%&'"%( respectively , 0.Tech !!! 5IIth semester here$y declare that, the

project report titled, -T( %!SI*+ " 0"SI6 2&!"M2)I7I!& 6I&6IT 08

SI+* " 2I!9(!)6T&I6 0"S!% %IS6 is an original work done $y us

under the guidance of Ms. Supriya Sharma and has $een not su$mitted to any

other university or institute of the award of any degree or diploma or fellowship.

Date3

Enroll2ent Nu2ber3'()*+,'+(*- Karti% "!!al

'(/*+,'+(*- Tusar Mittal

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A4STRACT

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In the world of electrical music instruments there is a growing need to convert

all musical output in an electrically amplified form. " lot of instruments

acoustics# are limited to amplification using menial amplification microphones

which compromise a lot on /uality. The $asic idea is to develop a cheapalternative for electrical amplification $y using existing means of technology

and instruments. (ne such alternative is making use of pie:oelectric discs which

make use of the concepts of pie:oelectricity. 6oupled with appropriate circuitry

and appropriate electrical components, along with the correct knowledge a$out

them results in the construction of a pie:oelectrical $ased contact mic

preamplifier. The main purpose is to enlighten people a$out the $enefits of

using this construction as a cheaper and effective alternative to other

mainstream methods of electrical amplification.

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TA4LE OF

CONTENTS

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S0No0 TO5IC 5age No0

*0 INTROD"CTION */

4ac%ground *6

Ob1ecti#e O7 Re!ort *(

Sco!e -)

Outline -/

-0 Literature Re#ie8 -6

)0 Metod )6

+0 Results )(

/0 Ad#antages and Li2itations +*

60 Conclusions +)

90 Re7erences +/

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LIST OF

A44RE:IATIONS

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*. FET 4 7ield !ffect Transistor

-. INR 4 Indian +ational &upees

). Mic 4 Microphone

+. DC 4 %irect 6urrent

/. AC 4 "lternating 6urrent

6. MOSFET 4 Metal (xide Semiconductor 7ield !ffect Transistor

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LIST OF FIG"RES

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7igure ;4 2ie:oelectric %isc

7igure


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INTROD"CTION

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4ACKGRO"ND

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The need for an alternative method of acoustic sound amplification arose when

we were exploring the option of successfully converting the sound of an

acoustic Indian musical instrument called the Sarod. "lso, we were exploring

the avenues of electrifying an acoustic guitar so as to get an amplified sound

output from it. "fter researching in the market as well as various information

sources, we reali:ed that most of the methods used in the mainstream were

either very expensive or had very low efficiency. 7or example, one can use a

simple microphone to amplify any sound however it severely affects the /uality

of the output sound. The other option is of suing magnetic pickups. This method

is highly efficient and is the most commonly used construction in guitar

amplification. 'owever its $iggest limitation was its cost. !ven the cheapest of

the guitar pickups of sufficient efficiency cost no less than I+&


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7igure 4;#4 2ie:oelectric %isc

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O4;ECTI:E OF

RE5ORT

To develop a working model of a preamplifier that is $ased on pie:oelectric

$ased contact mic discs.

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SCO5E

The foremost application will $e to generate awareness a$out the existence of

such cheap and effective means of sound amplification as opposed to some

mainstream methods. &ight now, the immediate target would $e an audience of

$eginner musicians. 0eing music enthusiasts ourselves, we have a social circles

comprising of likeminded people, from $eginner musicians to professional

instrumentalists. Thus, a safe consensus was made from inputs o$tained

through interactions and personal experiences that for the purpose of learning

new musical instruments, electrically amplified instruments are much easier to

learn than their respective acoustic versions. This can result from a variety of

reasons.

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;. In the case of guitars, it often happens that the chords $eing played

on an acoustic guitar do not really sound the way they are supposed

to.


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O"TLINE

SC


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7igure <

The deformations of the crystal create some electrical signal which is applied to

the inputs of the circuit. It is made to have a high input impedence at the output

so that the maximum signal can $e transferred. This signal is then amplified to

with the 7!T with a coupling capacitor connected to provide a low impedence

path for the ripples generated. The signal is then transferred across the ;.>k

resistor which is fed to the amplifier.

It’s $asically a standard 7!T differential amplifier with a couple of tricks to

keep the component count and noise down and input impedence up. It takesadvantage of the fact that phantom power is fed to the $alanced ?)& inputs via

pair of closely matched resistors. These resistors are used directly as the drain

resistors in the differential amplifier rather than the more usual method of

connecting an additional pair of matched resistors to each line to create a @AB5

supply rail and then feeding the signal $ack through %6 $locking capacitors.

Since the mixing desk already $locks %6 at its inputs it’s not a pro$lem that the

signal is floating at @A>5 or so.

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The two capacitors are %6 $locking capacitors to stop the pie:o element

floating at C5, if the pie:o is insulated you can dispense with them $ut they’re

so small that they’re worth it for peace of mind D if the pie:o touches a

grounded o$ject it’ll create a huge $ang which may hurt your speakers or your

ears.

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LITERAT"RE

RE:IEW

RESISTOR

&esistors are electronic components which have a specific, never4

changing electrical resistance. The resistor’s resistance li2its te 7lo8 o7

electrons through a circuit. They are !assi#e components, meaning they only

consume power and can’t generate it#. &esistors are usually added to circuitswhere they complement acti#e components like op4amps, microcontrollers, and

other integrated circuits. 6ommonly resistors are used to limit current, divide

voltages, and pull4up I1( lines. The electrical resistance of a resistor is

measured in o2s. The sym$ol for an ohm is the greek capital4omegaE F

Schematic sym$olE "ll resistors have t8o ter2inals, one connection on each

end of the resistor. 3hen modelled on a schematic, a resistor will show up as

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https://learn.sparkfun.com/voltage-current-resistance-and-ohms-law/resistancehttps://learn.sparkfun.com/tutorials/integrated-circuitshttps://learn.sparkfun.com/tutorials/voltage-dividershttps://learn.sparkfun.com/tutorials/voltage-dividershttps://learn.sparkfun.com/tutorials/pull-up-resistorshttps://learn.sparkfun.com/tutorials/integrated-circuitshttps://learn.sparkfun.com/tutorials/voltage-dividershttps://learn.sparkfun.com/tutorials/voltage-dividershttps://learn.sparkfun.com/tutorials/pull-up-resistorshttps://learn.sparkfun.com/voltage-current-resistance-and-ohms-law/resistance


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‘

CA5ACITORS

6apacitors are conductors usually plates# that are separated $y a dielectric

material. The plates accumulate electric charge when connected to power

source. (ne plate accumulates positive charge and the other plate accumulates

negative charge. The capacitance is the amount of electric charge that is stored

in the capacitor at voltage of ; 5olt. The capacitance is measured in units

of 7arad 7#.

The capacitor disconnects current in direct current %6# circuits and short

circuit in alternating current "6# circuits.

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http://www.rapidtables.com/electric/farad.htmhttp://www.rapidtables.com/electric/farad.htm


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Schematic sym$olE 3hen modelled on a schematic, a capacitor will show up as

5ERF4OARD

P*r+,-ard is a material for prototyping electronic circuits also called %(T

260#. It is a thin, rigid sheet with holes pre4drilled at standard intervals across a

grid, usually a s/uare grid of A mm =.; in# spacing. These holes are ringed

$y round or s/uare copper pads. Inexpensive perf$oard may have pads on only

one side of the $oard, while $etter /uality perf$oard can have pads on $oth sides

plate4through holes#. Since each pad is electrically isolated, the $uilder makes

all connections with either wire wrap or miniature point to point wiring

techni/ues. %iscrete components are soldered to the prototype $oard such

as resistors, capacitors, and integrated circuits. The su$strate is typically made

of paper laminated with phenolic resin or a fi$erglass4reinforced epoxy laminate

7&4A#.0efore $uilding a circuit on perf$oard, the locations of the components

and connections are typically planned in detail on paper or with software tools.

M5F*'- MOSFET transistor dataseet

Type %esignatorE M27;=<

Type of M27;=< transistorE G7!T

Type of control channelE + 46hannel

Maximum power dissipation 2d#, 3E =.H>

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https://en.wikipedia.org/wiki/Prototypinghttps://en.wikipedia.org/wiki/Electronic_circuitshttps://en.wikipedia.org/wiki/Via_(electronics)https://en.wikipedia.org/wiki/Wire_wraphttps://en.wikipedia.org/wiki/Point_to_point_wiringhttps://en.wikipedia.org/wiki/Resistorhttps://en.wikipedia.org/wiki/Capacitorhttps://en.wikipedia.org/wiki/Integrated_circuithttps://en.wikipedia.org/wiki/Phenolic_resinhttps://en.wikipedia.org/wiki/FR-4https://en.wikipedia.org/wiki/Electronic_design_automationhttps://en.wikipedia.org/wiki/Prototypinghttps://en.wikipedia.org/wiki/Electronic_circuitshttps://en.wikipedia.org/wiki/Via_(electronics)https://en.wikipedia.org/wiki/Wire_wraphttps://en.wikipedia.org/wiki/Point_to_point_wiringhttps://en.wikipedia.org/wiki/Resistorhttps://en.wikipedia.org/wiki/Capacitorhttps://en.wikipedia.org/wiki/Integrated_circuithttps://en.wikipedia.org/wiki/Phenolic_resinhttps://en.wikipedia.org/wiki/FR-4https://en.wikipedia.org/wiki/Electronic_design_automation


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Maximum drain4source voltage ds, 5E

Maximum gate4source voltage gs, 5E J.>

Maximum drain current Id, "E =.=<

Maximum junction temperature Tj#, K6E ;>>

&ise Time of M27;=< transistor tr#, nSE

%rain4source 6apacitance 6d#, p7E

Maximum drain4source on4state resistance &ds#, (hmE

2ackageE T(4L<

5IE=OELECTRIC EFFECT

2ie:oelectric !ffect is the a$ility of certain materials to generate an electric

charge in response to applied mechanical stress. The word 2ie:oelectric is

derived from the *reek pie:ein, which means to s/uee:e or press, and pie:o,

which is *reek for -push. (ne of the uni/ue characteristics of the pie:oelectriceffect is that it is reversi$le, meaning that materials exhi$iting the direct

pie:oelectric effect the generation of electricity when stress is applied# also

exhi$it the converse pie:oelectric effect the generation of stress when an

electric field is applied#.

3hen pie:oelectric material is placed under mechanical stress, a shifting of the

positive and negative charge centers in the material takes place, which then

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results in an external electrical field. 3hen reversed, an outer electrical field

either stretches or compresses the pie:oelectric material.

The pie:oelectric effect is very useful within many applications that involve the production and detection of sound, generation of high voltages, electronic

fre/uency generation. The pie:oelectric effect also has its use in more mundane

applications as well, such as acting as the ignition source for cigarette lighters.

DIRECT AND IN:ERSE 5IE=OELECTRIC EFFECT

2ressure generates charges on the surface of pie:oelectric materials. This direct

pie:oelectric effect, also called generator or sensor effect, converts mechanical

energy into electrical energy. 5ice versa, the inverse pie:oelectric effect causes

a change in length in this type of materials when an electrical voltage is applied.

This actuator effect converts electrical energy into mechanical energy.

The pie:oelectric effect occurs $oth in monocrystalline materials and in

polycrystalline ferroelectric ceramics. In single crystals, an asymmetry in the

structure of the unit cells of the crystal lattice, i.e. a polar axis that forms $elow

the 6urie temperature T6 , is a sufficient prere/uisite for the effect to occur.

5IE=OELECTRIC MATERIAL

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The commonly used pie:oelectric material is uart:Si(


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5REAM5LIFIER

The term microphone preamplifier can either refer to the electronic circuitry

within a microphone, or to a separate device or circuit that the microphone is

connected to. In either instance, the purpose of the microphone preamplifier is

the same.

" microphone preamplifier is a sound engineering device that prepares

a microphone signal to $e processed $y other e/uipment. Microphone signals

are often too weak to $e transmitted to units such as mixing

consoles and recording devices with ade/uate /uality. 2reamplifiers increase a

microphone signal to line level i.e. the level of signal strength re/uired $y such

devices# $y providing sta$le gain while preventing induced noise that would

otherwise distort the signal

LIMITATIONS

!ach pie:oelectric material has a particular operating limit for temperature,

voltage, and stress. The particular chemical composition of the material

determines the limits. (perating a material outside of these limitations may

cause partial or total depolari:ation of the material, and a diminishing or loss of

pie:oelectric properties.

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https://en.wikipedia.org/wiki/Sound_engineerhttps://en.wikipedia.org/wiki/Microphonehttps://en.wikipedia.org/wiki/Electrical_signalhttps://en.wikipedia.org/wiki/Mixing_consolehttps://en.wikipedia.org/wiki/Mixing_consolehttps://en.wikipedia.org/wiki/Sound_recordinghttps://en.wikipedia.org/wiki/Line_levelhttps://en.wikipedia.org/wiki/Gain_(electronics)https://en.wikipedia.org/wiki/Sound_engineerhttps://en.wikipedia.org/wiki/Microphonehttps://en.wikipedia.org/wiki/Electrical_signalhttps://en.wikipedia.org/wiki/Mixing_consolehttps://en.wikipedia.org/wiki/Mixing_consolehttps://en.wikipedia.org/wiki/Sound_recordinghttps://en.wikipedia.org/wiki/Line_levelhttps://en.wikipedia.org/wiki/Gain_(electronics)


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Te2!erature Li2itations

"s the operating temperature increases, pie:oelectric performance of a material

decreases, until complete and permanent depolari:ation occurs at the materialOs

6urie temperature. The 6urie point is the a$solute maximum exposure

temperature for any pie:oelectric ceramic. !ach ceramic has its own 6urie

point. 3hen the ceramic element is heated a$ove the 6urie point, all

pie:oelectric properties are lost. In practice, the operating temperature must $e

su$stantially $elow the 6urie point.

The materialOs temperature limitation decreases with greater continuous

operation or exposure. "t elevated temperatures, the ageing process accelerates,

pie:oelectric performance decreases and the maximum safe stress level is

reduced.

:oltage Li2itations

" pie:oelectric ceramic can $e depolari:ed $y a strong electric field with

polarity opposite to the original poling voltage.

The limit on the field strength is dependent on the type of material, the duration

of the application, and the operating temperature. The typical operating limit is

$etween >==51mm and ; ===51mm for continuous application.

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It should $e noted that alternating fields can have the same affect during the half

cycle which is opposite to the poling direction.

Mecanical Stress Li2itations

'igh mechanical stress can depolari:e a pie:oelectric ceramic. The limit on the

applied stress is dependent on the type of ceramic material, and duration of the

applied stress. 7or dynamic stress impact ignition# the limit is less severeP

materials with higher energy output high g constant# can $e used.

7or impact applications, the material $ehaves /uasi statically non4linear# for

pulse durations of a few milliseconds or more. 3hen the pulse duration

approaches a microsecond, the pie:oelectric effect $ecomes linear, due to the

short application time compared to the relaxation time of the domains

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-Indeed, gas lighters used in most homes are $ased on this. These future

pie:oelectric nanodevices will also generate an electrical current in response to

mechanical stimuli. Then, the energy will $e stored in $atteries or, even $etter, in

nanocapacitors for use when needed, he adds. The main issue the scientistOs team

needs to overcome is understanding exactly how flexoelectricity D the $asic

principle $ehind pie:oelectric materials D appears in nature.

7lexoelectricity, at the nanoscale, allows you to coax ordinary material to $ehave

like a pie:oelectric one. 2erhaps more importantly, this phenomenon exists in

materials that are already pie:oelectric.

MET


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># mpf ;=< transistor

Q# ;=, A.J uf 6apacitors

J# H.HM(hm, ;.>k(hm, >Q= ohm, and


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RES"LTS

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The working model of a preamplifier was made using pie:oelectric contact mic

disc. The working of the model was tested $y connecting it with an acoustic

guitar and o$serving its output through an amplifier. The cost incurred to make

this project was I+& H>=. This was found to $e a fraction of the cost that would

take to make may other mainstream method.

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AD:ANTAGES ANDLIMITATIONS

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AD:ANTAGES O:ER TRADITIONAL G"ITAR 5ICK"5S3

*. C This is the $iggest factor to advocate its use. " normal

pickup cost several thousands for example4 The cheapest %iMar:io guitar

pickup costs upwards of " 2ie:o 2remplifier tuned for a specific "mplifier

would give an inferior sound with another amplifier.

-. LACK OF 4ASS > These preamplifiers are effective filters for $ass sound

which makes their sounds a $it tinny or metallic. 'owever, it is not that

significantly trou$lesome.

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CONCL"SION

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The o$jective of the project was to develop a working model of a preamplifier

that was $ased on pie:oelectric contact mic disc. The idea was to enlighten the

general pu$lic a$out cheap and effective alternative methods that are not

availa$le in the market. The design of the entire project is /uite simple $ut its

novelty lies in its simplicity.

3hile guitar pickups are still predominant in the market, this is an upcoming

techni/ue. Many consider it $e just a hack to amplifying. 'owever, a growing

section of professionals advocate its use especially for $eginners. It is

considered an exciting new avenue in guitar amplification and many have set

eyes on it for future developments.

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REFERENCES

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WE4SITES

;. httpE11www.:achpoff.com1diy4resources1alex4rice4pie:o4preamplifier1

. httpE11www.musicofsound.co.n:1$log1the4first4rule4of4contact4mic4clu$

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http://www.zachpoff.com/diy-resources/alex-rice-piezo-preamplifier/http://www.leafcutterjohn.com/http://www.youtube.com/collinslabhttp://www.zachpoff.com/diy-resources/alex-rice-piezo-preamplifier/http://www.leafcutterjohn.com/http://www.youtube.com/collinslab


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dyi: piezoelectric contact mic

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