EE3 Laboratory Manual V1.8a - PDFCreator Soft Fonts

8/13/2019 EE3 Laboratory Manual V1.8a - PDFCreator Soft Fonts

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Acknowledgements

" #ould li$e to ac$no#ledge and t%an$ t%e man& people #%o %ave contributed to t%e re'

design and development of EE3. "n particular t%e )%air of t%e Department ofEngineering Professor *ran$ )%ang #as instrumental in providing t%e resources of staff

and funding necessar& to develop t%e ne# course.

Professor +reg Pottie developed t%e ne# lecture format and content of t%e course and

greatl& assisted in t%e development of t%e laborator& part.

Professor ,illiam -aiser provided valuable suggestions on t%e use of t%e " m&D/

device t%at %as been included in support of t%e laborator& portion of t%is course.

Dr. Mic%ael riggs is t%an$ed for %is generous insig%t into t%e c%anges t%at needed to be

made to improve t%e program based on %is eperience #it% t%e previous EE3.

Previous students of EE3 gave us man& suggestions t%at #e %ave attempted to include in

t%e re'design of t%is important "ntroduction to Electrical Engineering.4

*inall& " t%an$ t%e Elenco )orporation for t%e generous use of t%eir cop&rig%ted

materials.

'Prof Oscar Stafsudd 2012


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,ee$


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EQUIPMENT AND DEVICES

Introduction

6%e purpose of t%is laborator& is to provide t%e student #it% eperience in using t%e basic

measurement tools and an opportunit& to appl& t%ese tools to a term proCect. 6%e subCect

areas include@

1. Multi'meters2. *unction generators3.

Po#er supplies


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2

EE3 Laboratory Safety Course Certificate

F6E/> O56 6G"S P/+EH

S"+ /D D/6E 6G"S )E>6"*")/6E /D 65> " 6O ?O5> 8/O>/6O>?

6E/)G"+ /SS"S6/6 ,GE ?O5 G/7E S5))ESS*588? )OMP8E6ED 6GE

E)ESS/>? S/*E? )O5>SE(S!

" certif& t%at " %ave ta$en and passed t%e 5)8/ 8aborator& Safet& )ourse and all

necessar& additional safet& courses. " #ill abide b& t%e safet& reuirements for EE3

"ntroduction to Electrical Engineering4.

Date@ IIIIIIIIIIIIIIIIIIIIIIII

Student "D@ IIIIIIIIIIIIIIIIIIIIIIII

ame (Print ame )learl&!@ IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

Signature@ IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII


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3

MultiMeters

6%e multiple function meter more commonl& referred to as t%e multi'meter is t%e mostbasic of electrical measurement devices. 6%ese meters occur in t#o basic t&pes@ t%e analog

multi'meter (/MM! and digital multi'meter (DMM!. /lt%oug% t%e t#o t&pes perform

similar measurements t%eir met%ods differ and t%eir limitations are uite different.

Analo! MultiMeters "AMMs#

FSee /ppendi for additional information.H

/t t%e %eart of all analog meters is a current measuring device (see *igures 1a and 1b!.

6%e meter #or$s as follo#s@ t%e current passing t%roug% a coil produces a torue due to

t%e magnetic field across t%e coil. 6%is torue t%en acts against a spring and moves anindicator %and. 6&pical meters reuire 10

'1to 10

'Aamperes to deflect t%e indicator %and to

full scale. 6%e mec%anism is generall& mec%anicall& delicate and does not li$e p%&sical

s%oc$s i.e. dropping. 6%e accurac& is in t%e order of A'10J. 6%e electrical euivalent

circuit is s%o#n in *igure 2 #%ere t%e resistance of t%e coil and its connections are lumped

into >i(t%e internal resistance of t%e meter!.

*"+5>E 1a@ //8O+ M586"'ME6E>


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>int. 6%erefore a meter

#ill %ave multiple values of >intto be selected.


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*"+5>E S)/8E

/n analog meter can also be used to measure current. 6o do t%is t%e meterQs terminals are

placed in series #it% t%e current to be measured (*igure A!. ote t%at if one does not #is%

to perturb t%e circuit b& t%e measurement process t%en t%e resistance >int s%ould ideall&

be 0 o%ms. Since t%is is not possible one must consider t%e effect of t%e >intresistance ont%e circuit. 6&picall& if >intRR t%e resistors in t%e circuit t%ere #ill be a negligible effect

on t%e accurac& of t%e measurement.

*"+5>E A@ )5>>E6 ME/S5>"+ )">)5"6


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Di!ital MultiMeters "DMMs#

FSee /ppendi ) for additional informationH

Digital multi'meters currentl& dominate t%e mar$et. 6%eir advantages over analog meters

include@

1. "ncreased accurac&. /nalog meters are t&picall& no better t%an a fe# percentaccurate. Even ver& lo# cost digital meters are 0.1J or better in accurac&.

2. Mec%anical ruggedness. /nalog meters %ave delicate mec%anical metermovements #%ic% tend to be easil& damaged b& dropping etc.

3. Gig%er input resistance t%an possible #it% analog meters. 6&pical values eceed109o%ms.

esistance is measured b& a DMM b& putting a precision constant current source at t%e

measuring terminals. 6%en a resistor connected at t%e terminals #ill produce a voltage

drop proportional to bot% t%e resistor value in o%ms and t%e current source in amperes. /

significant advantage of t%is met%od of resistance measurement over t%e /MM is t%at t%e

readout is linear as long as t%e current source remains ideal. 6%e 0'2 7 measurement meter

#it% a 1 micro'ampere current source becomes a 0'2 mega'o%m device. & c%anging t%e

value of t%e constant current source t%e range can be adCusted.

6%e measurement met%od emplo&ed b& DMMs is to compare t%e voltage to be measured

to internall& generated voltages. 6%e internal voltage is c%anged until a matc% of sufficient

accurac& is ac%ieved. ecause t%e eternal voltage to be measured is compared it is

possible to ma$e t%e effective input resistance reac% etremel& large values and t%erefore

not interfere #it% t%e accurac& of t%e measurement. 6&pical DMMs in t%e voltage

measurement mode %ave effective input resistances in t%e 10 to


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6#o basic digital measurement met%ods are used in most DMMs. 6%e& are (1! t%e

integrator met%od and (2! t%e successive approimation met%od. 6%e integrator met%od

compares t%e eternal voltage to be measured (7m! #it% t%e voltage on a capacitor. /constant current source is connected to t%e capacitor and a digital timer is simultaneousl&

started. 6%e voltage on t%e capacitor 7cK c #%ere is t%e c%arge on t%e capacitor in

coulombs and c is t%e capacitance in farads. 6%e c%arge at 6K0 is set to ;ero and t%e

c%arge at time 6 is .

*or a constant current " t%e c%arge at time 6 is K "6 and

t%erefore t%e voltage on t%e capacitor is given as 7cK "6). 6%e voltage 7c is a linear

function of time. ,%en t%e comparator circuit detects t%at 7cK 7m t%e timer is stopped.

6%e digital value of t%e time represents t%e voltage t%at #as measured. "n realit& t%e

measurement is a bit more complicated if capacitors are not perfect and suffer from

various problems. 6o minimi;e t%e non'ideal nature of capacitors t%e circuit actuall&

measures t%e time to c%arge t%e capacitor and t%en to disc%arge it in order to ma$e t%e

measurement more accurate. Suc% circuits easil& ac%ieve 11000 accurac&.

Successive approimation t&pes of DMMs can ac%ieve %ig%er accuracies and %ig% speeds.

"n t%is t&pe of digital meter voltages produced b& a digital to analog converter (D/)! are

compared seuentiall& #it% increasing accurac&. 6%e internal voltage is produced b&

c%anging t%e value of resistors s#itc%ed across a constant current source. 6%e internal

voltage starts at 7Ma."f t%e eternal voltage to be measured 7mis greater t%an 7Mat%en

t%e instrument displa&s over range4. "f t%e eternal voltage is smaller t%an 7Ma t%en t%e

internal voltage is c%anged to 7Ma 2.

6%e voltages eternal and internal are compared again. "f t%e eternal voltage is smaller

t%an 7Ma 2 t%en t%e internal voltage is reduced to 7Ma


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$unction %enerators

*unction generators are time dependent voltage sources. 6%e& fall into t#o distinct t&pes@analog and digital. ?ou #ill %ave an opportunit& to use and familiari;e &ourself #it% bot%

t&pes.

/nalog function generators of t%e simplest t&pe produce sinusoidal and suare #aves i.e.

#aves #%ose voltage as a function of time are given b& 7(t! K 70sin(Ut! in t%e case of

sine #aves or #aves t%at alternate bet#een 70#it% a minimum of rise and fall time (see*igure =!. *reuentl& triangular #ave forms are also available in analog function

generators. / triangular #ave rises linearl& for N70to L70and t%e falls linearl& from L70

to N70successivel&.

*"+5>E =@ //8O+ *5)6"O +EE>/6O>

6%ese #ave forms can easil& be produced b& relativel& simple analog circuits. More

comple #ave forms suc% as modulated or gated repetitive sine suare or triangular #ave

forms can also be easil& produced. Go#ever for arbitrar& functions of time one s%ould

use a digital function generator.

Digital function generators are based on Digital to /nalog )onverters (D/)s! as are some

digital multi'meters. / series of numbers stored in a memor& is sent seuentiall& into a

D/). 6%e D/)Qs output as a function of time is t%en determined b& t%e arra& of numbers

stored in t%e memor&. 6%e series of voltage outputs produced b& t%e D/) can be used to

approimate an& arbitrar& function limited onl& b& t%e speed of t%e D/) and t%e si;e of

t%e memor&. 6%is series can be repeated to give a repetitive function or occur as a single

occurrence.


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6%e " m&D/ %as suc% an arbitrar& #aveform generator included as one of its

functions. Eac% t&pe of function generator (analog and digital! %as its advantages and

disadvantages so bot% s&stems continue to be popular and in production.


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Po&er Su''lies

6%e laborator& is euipped #it% 6e$troni dual po#er supplies #%ic% %ave variable outputvoltages and current limits (*igure 9!. 6%ese supplies act as almost perfect voltage

sources. 6%at is t%e& suppl& a constant output voltage regardless of current demand up to

t%e pre'set current limit at #%ic% point t%e& be%ave as current sources suppl&ing a fied

current even into a s%ort circuit N ;ero o%msV

*"+5>E 9@ D) PO,E> S5PP8?


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(scillosco'es

Oscilloscopes allo# us to displa& time dependent #ave forms. 6%e original scopes4 #ereanalog devices. 6%e signal to be displa&ed #as amplified and t%e amplified signal #as

t%en used to displace an electron beam verticall&. 6%e displacement #as usuall&

accomplis%ed electrostaticall&. 6%e %ori;ontal pat% of t%e beam #as determined b& a

second amplifier circuit. 6%e %ori;ontal position #as commonl& a linear function of time.

6%us t%e beam of electrons #as positioned %ori;ontall& as a linear function of time and

verticall& b& t%e signal. 6%e electron beam struc$ a front surface of t%e cat%ode ra& tube

#%ere a p%osp%or surface #as present. 6%e electron impact caused t%e p%osp%or to

fluoresce (lig%t up brig%tl&!. 6%e #ave form as a function of time #as displa&ed.

6%is met%od #as a maCor step for#ard at t%e time allo#ing t%e engineer to visuali;e t%etime dependent voltage. /nalog oscilloscopes #ere emplo&ed from t%e 1:30Qs t%roug% t%e

end of t%e 20t%centur&. Digital tec%nolog& in t%e form of fast analog to digital converters

along #it% advances in displa& tec%nologies led to t%e digital oscilloscope #%ic% %as

become t%e dominant tec%nolog& toda&.

6%e t&pical digital oscilloscope still amplifies and per%aps conditions t%e signal. 6%e time

dependent signal is t%en converted to digital information b& an analog to digital converter

(/D)!. 6%e sampling rate is continuousl& deposited in a *"*OType equation here.(firstin N first out! memor&. 6%e memor& is a certain number of addresses long (t&picall&


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ecause t%e data is in digital form man& mat%ematical operations can be performed suc%

as averaging addition subtraction division etc. of t#o or more different #aveforms. 6%e

data can also be transferred to a removable memor& allo#ing t%e operator to furt%eranal&;e or arc%ive t%e data.


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1int t%e euivalent internal resistor. 6%e non'ideal voltagesource approac%es ZidealQ as >int\ 0.

F6%e on'"deal 7oltage Source is also called a 6%evenin SourceH

Current Sources

)urrent sources also occur in ideal and non'ideal t&pes. /n ideal current source delivers a

constant current no matter #%at voltage is reuired. 6%e& are usuall& s%o#n b& double

circles #it% an arro# s%o#ing t%e direction of t%e current. Occasionall& &ou ma& also see

a diamond s%ape for a current source particularl& on +erman and *renc% circuit diagrams.

on'ideal sources are usuall& represented b& an ideal source #it% an internal parallel

resistor.

V

V

*deal Voltage +our,e

V

V

Rint

-on*deal Voltage +our,e

Rint

* *

*deal Current +our,e

*

-on*deal Current +our,e

Rint


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F6%e on'"deal )urrent Source is also called a orton SourceH

6%e non'ideal source approac%es ZidealQ as >int\ .

One can use a constant voltage source to simulate a nearl& ideal constant current source b&

placing a ver& large resistance in series i.e.

6%e current t%roug% t%e load resistor >8can be found as@

70K i ( >8L >S!.

6%erefore

" K 70 (>SL >8!

"f >S]] >8 t%en i ^70>S (a constant value providing >S]] >8!.

,e #ill not %ave &ou perform current source eperiments at t%is time because current

#easure#ents are the easiest way to destroy a #eter.

MultiMeter Measure)ents

1. Pic$ = resistors #it% different color codes. Measure t%eir values #it% &our DMMand /MM. )ompare t%eir stated values and tolerances (color code! #it% &our

measured multi'meter results.

,O>- SGEE6 GE>E@

>esistor _ Mar$ed DMM J Deviation /MM JDeviationMeasured Measured

>1 IIIIIIII IIIIIIII IIIIIIII IIIIIII IIIIIIII



>


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>A IIIIIIII IIIIIIII IIIIIIII IIIIIII IIIIIIII

>= IIIIIIII IIIIIIII IIIIIIII IIIIIII IIIIIIII

"s t%e error4 or deviation4 greater or less t%an t%e indicated tolerance`

/S,E> GE>E@

2. "f &ou loo$ at a standard list of 20J resistors available &ou #ill see 1000 o%msand 1A00 o%ms but not 1200 o%ms. ,%&` "f &ou loo$ at AJ resistors #ould t%e

results be different` ,%&` F/ listing of resistor values can be found on t%e #all of

t%e laborator&.H

/S,E> GE>E@

3. Pic$ t#o resistors t%at are approimatel& t#o orders of magnitude different i.e.1000 and 100000 or 22 and 2200 (See *igures 13 1- SGEE6 GE>E@

>1)olor )ode 7alue@ IIIIIIIIIIIIII >1Measured 7alue@ IIIIIIIIIIIIII

>2)olor )ode 7alue@ IIIIIIIIIIIIII >2Measured 7alue@ IIIIIIIIIIIIIII

b. Measure t%em in series and parallel connections.,O>- SGEE6 GE>E@

>Series7alue@ IIIIIIIIIIIIII >Parallel 7alue@ IIIIIIIIIIIIII

c. )ompare &our measurements #it% t%e calculated values. ote@ in series t%elarger value dominates t%e measurement.

,O>- SGEE6 GE>E@

> Series >esistance )alculated@ IIIIII Measured@ IIIIIII J difference IIIIIII

> Parallel >esistance )alculated@ IIIII Measured@ IIIIIII J difference IIIIIII


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d. "n t%e parallel connection #%ic% resistor dominates and #%&`/S,E> GE>E@

*"+5>E 13. M586"ME6E>S )OE)6ED

6O >ES"S6O> O P>O6O'O/>D

F8eft side@ /nalog Multimeter >ig%t side@ Digital MultimeterH


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2:

*"+5>E 1ES"S6O>S )OE)6ED " SE>"ES O P>O6O'O/>D

*"+5>E 1A. >ES"S6O>S )OE)6ED " P/>/88E8 O P>O6OO/>D

Source Measure)ents

6%e 6e$troni dual po#er suppl& &ou #ill be using can operate as a near ideal voltage

source and a near ideal current source (O6 simultaneousl&!.


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6o test a voltage source@

turn t%e current limit to full rig%t (cloc$#ise direction![ set t%e output to 10 volts[ set t%e DMM to read D) volts set t%e range to greater t%an 10 volts if available or auto'scale4 if t%e meter is so

euipped

Observe carefull& t%e small c%ange in t%e output voltage t%at #ill occur #%en t%e resistor

is connected. *rom t%e c%ange in t%is voltage calculate t%e internal resistance of t%e

voltage source. 6%e euivalent circuit is@

(6%e DMM input resistance is etremel& large compared to >V!

Measure t%e output voltage carefull& #it% t%e meter connected to t%e suppl&. 6%en

connect a 10 3A ,att resistor across t%e t#o output terminals #it% t%e po#er suppl& set

at approimatel& 10 volts. ote@ t%e resistor #ill dissipate energ& and get uite GO6VV

6a$e care not to burn &ourself. See *igure 1=. F6%e resistor ma& loo$ slig%tl& different.H

+

u

p

p

l

y

/

o

0

e

r

V

Rint

R&

1

M

M


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*"+5>E 1=. 10 OGM >ES"S6O> )OE)6ED

6O M586"ME6E> /D PO,E> S5PP8?

,O>- SGEE6 GE>E@

5nloaded voltage (i.e. O 10 O%m resistor!@ IIIIIIIIIIIIII

8oaded voltage (10 O%m resistor!@ IIIIIIIIIIIIII

7oltage s%ift@ IIIIIIIIIIIIIIIIIII

)alculate internal resistance@

o# eplore t%e problems represented b& a non'ideal voltage source. Set t%e output

voltage to about 10 volts. Put a 10 - resistor in line #it% t%e positive terminal. 6%is

combination simulates a non'ideal po#er suppl& (or source!. 6%e euivalent circuit %as

>int^ 10- .


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DMM Measure)ent

Set t%e po#er suppl& voltage to about 10 7. Measure t%e DMM D) voltage reading at t%epo#er suppl& terminals and also after t%e - SP/)E GE>E@

D) 7oltage at po#er suppl&@ IIIIIIIIIIIIIIIIIIIIIIIIIIIIII

D) 7oltage after - SP/)E GE>E@

FMeter set to 10 7H

D) 7oltage at po#er suppl&@ IIIIIIIIIIIIIIIIIIIIIIIIIIIIII

D) 7oltage after


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ote t%at t%e loading effect of t%e /MM is different on different scales. )an &ou eplain

t%is`

,O>- SP/)E GE>E@

6%is simple eperiment demonstrates t%e loading4 effect of t%e analog meter and #%& itQs

necessar& to be uite careful in simple voltage measurements.


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3MS 7pp K `

3. 6riangular ,ave@ >MS 7pp K `


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3A

Ti)e De'endent Measure)ents

6%is #ee$Qs eperiments #ill give &ou t%e opportunit& to learn t%e basic operations of an

oscilloscope and a function generator.

6urn on bot% t%e function generator (*igure 19! and oscilloscope (*igure 1!. )onnect

c%annel 1 input of t%e oscilloscope to t%e function generator signal out4. )onnect t%e

s&nc out4 of t%e function generator to t%e scopeQs c%annel 2 (,it% t%e digital generator

use t%e generatorQs )%annel 1 since t%e S&nc Out is onl& associated #it% )%annel 1.

Enable S&nc Out in t%e 5tilit& Mode!. Set t%e freuenc& to 100 G; #it% amplitude

some#%ere bet#een 1 7 and 10 7. Set t%e function generator mode to sine output

(sinusoidal #aves!. Press t%e auto scale button on t%e scope. ?ou s%ould observe a

sinusoidal #ave form on t%e displa& (*igure 1:!.

.*"+5>E 19a@ //8O+ Signal +enerator


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3=

*"+5>E 19b@ D"+"6/8 Signal +enerator (frontbac$!


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*"+5>E 1@ OS)"88OS)OPE

*"+5>E 1:@ S)OPE D"SP8/?"+ S"5SO"D/8 S"+/8


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6o understand t%e trigger function of t%e scope select t%e trigger control. /fter pressing

t%e upper'rig%t corner /utoSet4 button t%e trigger is internall& set b& t%e scope. ,%ile

t%is is a good start #e #is% to %ave more control. 6%erefore ta$e direct control b& firstselecting t%e trigger menu and setting t%e source to be c%annel 1. ,it% t%e trigger in

Edge4 mode t%e (trigger! 8evel4 $nob can no# be used to control t%e voltage level at

#%ic% t%e scope #ill start its measurement i.e. its time reference point or trigger point.

ote@ if a trigger voltage point is selected t%at is outside of t%e range of voltages on

c%annel 1 t%en t%e scope #ill not displa& ne# data and #ill indicate on t%e displa& not

triggered4 or #aiting for trigger4 etc.

6%e trigger level is noted on t%e displa& b& eit%er a line or an arro# #it% 6 net to it.

/dCust t%e trigger level to obtain an active displa&. 6%e displa& #ill no# sa& triggered4

or running4. /dCust t%e trigger level and note its effect on t%e position of t%e #ave formon t%e displa& screen.

ote t%e level control also allo#s t%e slope of t%e level to be observed. )%ange t%e slope

(or sense! from increasing to decreasing bac$ and fort% to note t%e effect on t%e displa&.

Set t%e trigger level about %alf#a& bet#een 0 and t%e maimum value of t%e #ave form.

o# adCust t%e voltage level of t%e function generator and note t%e position of t%e 04

time c%anges #it% amplitude and t%at as t%e voltage of t%e function generator gets small

t%e trigger #ill eventuall& fail to #or$.

o# c%ange t%e trigger input to c%annel 2 (s&nc output of t%e function generator!. ote

t%at t%e trigger #ill no# remain constant regardless of t%e magnitude of t%e sinusoidal

signal. 6%is is t%e prime reason for t%e use of a s&nc output of t%e function generator.

)%ange t%e mode of t%e function generator from sine to triangular and t%en suare. ote

eac% of t%ese #ave forms. 6%e actual voltage levels can be measured b& using t%e voltage

cursor function of t%e scope. 5sing t%e )5>SO> controls measure t%e 7pp amplitude of

a sinusoidal #ave i.e. t%e pea$'to'pea$ amplitude of t%e #ave.

5sing &our analog and digital multi'meters on t%e /) voltage settings measure t%e

voltage of t%e #ave form. )ompare t%e scope and multi'meter indicated voltages. Go# do

&ou eplain t%ese results`

o# c%ange t%e mode to suare and t%en triangular and repeat t%e eperiment.

6%e follo#ing are four sets of similar measurements comparing t%e DMM and /MM@

*irst t%e #aveforms are measured at lo# freuenc& (100 G;! and lo# level (A7pp! t%en

lo# freuenc& and %ig% level (207pp!. *ollo#ing t%ose pair of measurements &ou #ill

increase t%e freuenc& to A $G; and repeat t%e lo#' and %i'level measurements. *rom all

t%ese measurements &ou can observe t%e limitations of eac% instrument.


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3:

,O>- SGEE6 GE>E@

,ave Scope 7oltage Meter 7oltage (>MS! Difference ( J ! 7s )alc

*orm ()5>SO>! )alc DMM /MM DMM /MM

100 G; A 7pp 7rms 7rms 7rms 7rms 7rms

Sine@ IIIIIIII IIII IIIIIII IIIIIII IIIIIII IIIIIII

6riangle@ IIIIIIII IIII IIIIIII IIIIIII IIIIIII IIIIIII

Suare@ IIIIIIII IIII IIIIIII IIIIIII IIIIIII IIIIIII

"f t%ere are differences eplain@

/S,E> GE>E@

,O>- SGEE6 GE>E@



100 G; 20 7pp 7rms 7rms 7rms 7rms 7rms





/S,E> GE>E@


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- SGEE6 GE>E@



A $G; A 7pp 7rms 7rms 7rms 7rms 7rms





/S,E> GE>E@

,O>- SGEE6 GE>E@



A $G; 20 7pp 7rms 7rms 7rms 7rms 7rms





/S,E> GE>E@


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,/7E*O>M

"f &ou reduce t%e timebase to approimatel& 2A0 millisecondsdivision &ou #ill be

undersampling t%e #aveform and &ou #ill observe #aveforms similar to *igure 21.


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,/7E*O>M

?our 6/mentor #ill %elp &ou displa& t%is effect. ecause of undersampling &our scope

is displa&ing a lo# freuenc& #aveform #%ic% does not eist and is an artifact of aliasing

(&uist!. *igures 22 and 23 s%o# t%e same results for sinusoidal #aves.

*"+5>E 22@ )O>>E)68? S/MP8ED S"5SO"D/8 ,/7E*O>M

*"+5>E 23@ ")O>>E)68? S/MP8ED S"5SO"D/8 ,/7E*O>M

6%e 6/ and class mentors #ill demonstrate t%e use of t%e curve tracer and current sources

to t%e class as time permits.


47/122

/SD5)E>S MO56ED O P7) )O5P8E>S.

)onnect t%e s&nc output of t%e function generator to )%annel 1 of &our scope and set t%e

scope to trigger on )%annel 1 (6%is #ill be automaticall& done #%en &ou press t%e scopeQs

/utoSet button.! Select A $G; on t%e function generator and an output a level 3 7pp.

/lso ma$e sure t%e function generator is set to sine #aves. )ouple t%e t#o transducers

acousticall& b& placing a s%ort piece of P7) pipe bet#een t%em. 6%e pipe acts as a

#aveguide for t%e acoustic #aves. See *igure 2A.


48/122


49/122


50/122


51/122


52/122

pK 1 +p and +pK +0 L "

#%ere +0is t%e dar$ conductance (1 >0!. 6%is device %as a +0^ 10=o%m. rig%t lig%t

i.e. sunlig%t #ill produce a resistance of ^1 - o%m or less.

*"+5>E 2=@ 8E*6@ PGO6OD"ODE )E6E>@ PGO6OD"ODE

>"+G6@ PGO6O')OD5)6O>

?our 6/ or mentor can %elp &ou displa& t%e lig%t and dar$ c%aracteristics (current vs.

voltage! of t%e device on t%e curve tracer. 6%e correct range of t%e setup is 0 N 20 7 and


53/122

! and t%e device. 6%e

current can be calculated "DK 7> >. Measure t%e device in dar$ room lig%t and brig%t

lig%t using t%e lig%t bulb provided. ote@ in t%e dar$ a resistor value ^ 100 - o%ms is

appropriate and under brig%t lig%t 10 - or 1 - o%m.

Of t%e devices listed all t%e ot%ers are diodes t%at can eit%er generate lig%t (8EDs! or

absorb lig%t and generate current i.e. p%otodiodes p%oto transistors solar cells.

6%e current in a diode is a ver& non'linear and non's&mmetric function of voltage (see

*igures 29 and 2!. / reasonabl& accurate mat%ematical model of t%e current'voltagerelations%ip is@

"DK "0(e77t

N 1!

"n t%e for#ard direction i.e. 7 7t

"D^ "0 e77t

"n reverse 7 '7t t%en "D^ "0


54/122

A0

*"+5>E 29@ PGO6OD"ODE D/>- *O>,/>D )G/>/)6E>"S6")

*"+5>E 2@ PGO6OD"ODE D/>- >E7E>SE )G/>/)6E>"S6")


55/122

A1

*"+5>E 2:@ PGO6OD"ODE "885M"/6ED )G/>/)6E>"S6")

(*O>,/>D /D >E7E>SE!

ecause t%e currents in t%e for#ard and reverse directions are ver& different in si;e t%e

appropriate series resistors s%ould be c%anged. 6&picall& t%e reverse current is man&

orders of magnitude smaller t%an t%e for#ard current. Go#ever t%e po#er dissipation can

be large in t%e reverse direction because t%e voltage across t%e device can be uite large

(tens of volts!. "n t%e for#ard direction t%e t&pical voltage is in t%e order of a fraction of avolt for silicon devices and a fe# volts for 8EDs. 6%e suggested resistor values are in t%e

)urve 6racer "nstructions (See /ppendi /!. Observe t%e c%aracteristics.

ote@ t%e 8EDs actuall& emit lig%t in t%e for#ard direction. One possible future proCect for

&ou is to measure t%e lig%t output as a function of current andor voltage.

P,otodiodes

5nli$e 8EDs p%otodiodes are designed to absorb lig%t and convert it into electron %ole

pairs t%at generate a measurable voltage or current. / good circuit model for t%e

p%otodiode and its sc%ematic s&mbol are s%o#n %ere@


56/122

A2

Mat%ematicall&

"DK "0(e77tN 1! ' "gen

ote@ "genis in a direction to for#ard bias t%e diode.

Solar cells are designed to convert lig%t (t&picall& solar radiation! to electrical po#er.

)onversion efficiencies for silicon are 10J AJ and t%e solar radiation level in sunn&

sout%ern )alifornia is about 100 m.#.cm2. P%otodiodes for t%e purpose of lig%t detection

are t&picall& small area devices t%at are designed to give %ig% sensitivit& and lo# noise.

Devices s%o#n in *igure 2= %ave areas in t%e order of 10'

to 10'=

cm2. 6%e values of

current are 10'=

N 10'3

amperes and care must be ta$en not to inCure t%ese devices. 6%e

correct settings for t%e devices can be found in t%e )urve 6racer "nstructions. Please use

t%e assistance of &our 6/ or mentor to operate t%e curve tracer (*igure 30!.

*"+5>E 30. )5>7E 6>/)E>

Solar cells are onl& used in t%e for#ard direction i.e. for generating po#er. e sure to

loo$ at t%e for#ard c%aracteristic of &our single solar cell in t%e dar$ and illuminated.

One of t%e simplest uestions t%at can be of interest is #%at load value i.e. resistance #ill

&ield t%e maimum po#er` /nd does t%is c%ange #it% illumination level`

P%otodiodes are used bot% in t%e for#ard biased and reverse biased conditions. e sure to

measure t%e p%otodiodes bot% dar$ and illuminated in bot% for#ard and reverse biased

conditions. )onsider t%e t#o common p%otodiode circuits@ P7 P). 6%e P7 mode

reuires one less component (no batter&! and P) mode responds faster to c%anges in lig%t.


57/122

A3

,%at are t%e advantages of eac% circuit`

/S,E> GE>E@


58/122

Aeverse t%e direction of t%e spin and note t%at t%e voltage reverses.

et investigate t%e device as a motor$ %&'() the s#all #otor can be da#aged if

#ore than * + C is applied directly across the #otor, so we ask that you always use

one of the big, white -. oh# power resistors in series with each #otor you use

Set t%e po#er suppl& to 04 volts output #it% t%e current $nob turned full& ),. )onnect

t%e motor in series #it% a (#%ite! 10 o%m po#er resistor to t%e po#er suppl&Qs output

terminals and connect &our DMM to measure t%e voltage across onl& t%e motor. Ma$e

sure t%e motor is mec%anicall& separated from an& gears if t%e gear bo is assembled so

t%e motor is free to turn #it%out being loaded b& an& gears. Set t%e s#itc% on t%e suppl&

to indicate /mps and t%en var& t%e suppl& voltage until t%e voltage &ou measure across

onl& t%e motor is set to eac% of t%e values in t%e follo#ing table. /t eac% setting note t%e

current indicated on t%e suppl&Qs /mp reading. ote t%at t%e motor s%aft spins rapidl& at

t%e %ig%er voltages. Measure t%e current b& separatel& measuring t%e voltage across t%e

resistor and using O%ms la#.

Stop measurement if t%e motor stops running at lo# voltages. ever appl& more t%an 37

across t%e motor.


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AA

,O>- SGEE6 GE>E@

Motor 7olts Motor )urrent

2.A IIIIIII

2.0 IIIIIII

1.A IIIIIII

1.0 IIIIIII

0.A IIIIIII

0.2 IIIIIII

0.1 IIIIIII

Plot &our results@

,%at voltage and current "o is reuired to Cust start t%e motor spinning`

6%is current "0represents t%e current reuired to simpl& turn over t%e motor in t%e absence

of doing eternal #or$. /s$ &our 6/mentor to demonstrate t%e effects on t%e current of a

load reuiring t%e motor to do eternal #or$.


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A=

0ee1 6 NI )yDAQ

5sing t%e Elvis program t%e " m&D/ can be launc%ed into modes in #%ic% it emulatesvarious laborator& devices. Details on %o# to do t%is can be found at t%e #ebsite@

###.ni.com#%ite'paper11MS.

,O>- SGEE6 GE>E@

1 $G; )&clic >MS

,ave 6e$ Scope Meter 7oltage J Difference (7s Scope!

(A 7pp! 7oltage DMM m&D/DMM DMM m&D/

Sine@ IIIIIIII IIIIIII IIIIIII IIIIIII IIIIIII

6riangle@ IIIIIIII IIIIIII IIIIIII IIIIIII IIIIIII

Suare@ IIIIIIII IIIIIII IIIIIII IIIIIII IIIIIII

"n particular does t%e M&D/ measurement of sine suare #aves and triangular #aves

be%ave t%e same or differentl& t%an t%e digital multi'meter` ,%&`

/S,E> GE>E@


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A9

/ctivate t%e " m&D/ in (L+IS&scilloscope instrument. )onnect bot% t%e m&D/

and t%e 6e$troni scopes to t%e digital function generator. ote t%at t%e M&D/ analog

inputs are made t%roug% its edge connector and are differential (Cust li$e an Op/mp! #it%a non'inverting and a inverting terminal so &ou %ave to connect t#o #ires in order to

input t%e one signal. ?ou actuall& s%ould connect t%ree #ires for t%e one signal@

,%ic%ever input terminal (invertingnon'inverting! t%at &ou connect to &our signal

generatorQs ground () ground s%ield! &ou s%ould also connect t%at same terminal also

to t%e M&D/Qs analog ground terminal. (6%is minimi;es ground loop noise.!

)ompare t%e be%avior of t%e lab benc% 6e$troni and &our m&D/ oscilloscopes. Start

b& measuring t%e output of t%e function generator at about 1 $G; and amplitude of 1 N 10

7pp loo$ing at bot% sine and suare #aves. "ncrease t%e freuenc& of t%e function

generator to 1 -G; 10 $G; :: $G; ::: $G; and 1::: $G;. ote #%et%er t%e amplitudeof t%e sine #aves and particularl& t%e s%ape of t%e suare #aves remain constant. 6%e

digital function generator output is in fact constant over t%is freuenc& range so c%anges

in rise and fall time andor amplitude #it% freuenc& are t%e result of freuenc&

limitations in &our measuring devices. (6%e output of t%e analog function generator varies

some#%at over t%is freuenc& range.!

,O>- SGEE6 GE>E@

*reuenc& Oscilloscope >MS 7oltages IIIIIIIIIIIIIII

$G; Sine (6e$! Suare (6e$! Sine(m&D/! Suare (m&D/!

1 IIIIIIII IIIIIII IIIIIII IIIIIII

10 IIIIIIII IIIIIII IIIIIII IIIIIII

:: IIIIIIII IIIIIII IIIIIII IIIIIII

::: IIIIIIII IIIIIII IIIIIII IIIIIII

1::: IIIIIIII IIIIIII IIIIIII IIIIIII

Suare #ave response reuires a %ig%er freuenc& response from t%e measuring s&stemt%an sinusoidal #aves. /s &ou #ill see in t%e spectrum anal&;er eperiment suare #aves

can be t%oug%t of as being formed from a fundamental sinusoidal #ave #%ose period is

t%e same as t%e suare #ave #it% %ig%er freuenc& components (all odd %armonics! to

ma$e up t%e s%arp rise and flat top associated #it% t%e suare #ave.

6%erefore as &our measuring s&stem goes to its %ig% freuenc& limit t%e s%arp rise and

fall of t%e suare #ave #ill be lost due to t%e lac$ of t%ese %ig%er freuenc& components

being accuratel& displa&ed. Plot t%e sinusoidal freuenc& response versus freuenc& for

t%ese t#o oscilloscopes.


62/122

A

/S,E> GE>E@

,e define t%e upper freuenc& response of a s&stem to be t%e point at #%ic% t%e amplitude

decreases to 90.9J ('3 d!. 5sing t%is criterion can &ou estimate t%e freuenc& response

of t%e m&D/ and t%e 6e$troni oscilloscopes` Discuss.

/S,E> GE>E@

*rom t%ese eperiments &ou #ill observe t%at t%e combination of a laptop computer and a

" m&D/ can emulate t%e common functions of a standalone multi'meter or

oscilloscope.

6%e " m&D/ #ill also operate as a function generator. Put t%e device in function

generator mode and test its output using t%e 6e$troni oscilloscope. 6est various

#aveforms suc% as sine suare and triangular outputs.


63/122

A:

ote t%at t%e generator can also be used to generate arbitrar& #aveforms. 6%is #ill be

useful for t%e various proCects t%at &ou #ill c%oose to #or$ on. "n &our outside time

please eamine t%is option of generating arbitrar& #aveforms.

S'ectru) Analy*er Mode

Put t%e " m&D/ in spectrum anal&;er mode called a D&namic Signal /nal&;er4. 5se

t%e function generator to produce 1 $G; suare #aves of about 1 volt amplitude. /nal&;e

t%e spectrum of t%is suare #ave. )ompare t%e freuenc& components and t%eir

amplitudes to t%eor&. 6%at is onl& odd %armonics s%ould appear (1 $G; 3 $G; A $G;

etc.! and t%e ratio of t%e various %armonic amplitudes to t%at of t%e fundamental s%ould be

1 #%ere is t%e %armonic (1@ 13 @ 1A @ 19 @ W etc.!.

ote again@ t%e d&namic signal anal&;er can displa& t%e data in bot% a linear andlogarit%mic manner called d (decibel! defined as a ratio of po#ers@

ell K log10Po#er Po#erreference

d K 10 log10Po#er Po#erreferenceK 20 log107 7reference

6a$e t%e data bot% linearl& and logarit%micall&. 6%e logarit%m displa& gives greater detail

over a #ide d&namic range and is t%erefore commonl& used in engineering.

Set t%e **6 settings *re Span to 20 $G; *reuenc& Displa& 5nits to d and set t%e

Scale Settings Scale to Manual (Ma K 0 Min K 'un t%en clic$ t%e lo#er'left corner bo )ursors On4 drag t%e das%ed vertical green line (on t%e left side of t%e

displa&! %ori;ontall& until it snaps onto t%e first %armonic t%en drag t%e remaining second

das%ed vertical line to snap respectivel& on eac% of t%e %ig%er %armonics N one b& one.

Eac% time (snapped onto eac% of t%e %ig%er %armonics! note and record t%e value on t%e

left middle indicator in green as dd7rms (delta d!.


64/122

=0


65/122

=1

,O>- SGEE6 GE>E (S5/>E ,/7E //8?S"S!@

n 20 log(7n 71!Kdn'd1 20log(1n! nKodd[ 'inf nKeven

Garmonic >atio in d (n't% 1st! 6%eor& .

1 0 0

2

3

epeat t%e process #it% a triangular #aveform. )ompare t%e results to t%e t%eoretical

values.

,O>- SGEE6 GE>E (6>"/+58/> ,/7E //8?S"S!@

n 20 log(7n 71!Kdn'd1 20log(1n2! nKodd[ 'inf nKeven

Garmonic >atio in d (n't% 1st! 6%eor& .

1 0 0

2

3

EME6 SE6'5P

*"+5>E 32@ )8OSE'5P SGO,"+ 8ED /D SE>"ES >ES"S6O>


72/122


73/122

=:


74/122

90

et measure t%e lig%t output vs. device current. Put a single cell solar cell net to t%e

8ED. )onnect a multi'meter to t%e solar cell. 5se t%e meter in current mode4. See t%e

circuit diagram belo#. Put a s%ield over &our set up to avoid t%e effects of t%e laborator&lig%ts. 6%e 8ED is connected as before.

elo# is a picture of an /MM in current mode connected to a solar cell. ote@ it is asingle cell rated at h volt


75/122

91

elo# see t%e set'up for measuring t%e lig%t output of a 8ED.

*"+5>E 3E 3A. )/>DO/>D O 5SED /S 8"+G6 SG"E8D

O6E@ a Cac$et can also serve t%is purpose.


76/122

92

Measure t%e current from t%e solar cell #%ic% is linear in lig%t intensit& as a function of

8ED current. Put t%e /MM in current mode and on t%e 2.A m/ scale.

,O>- SGEE6 GE>E@

7olts (across 1-'o%m resistor! "Solar )ell "8ED

0.0 IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

1.0 IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

2.0 IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII


77/122

93

Plot t%e solar cell current i.e. t%e lig%t output vs. t%e 8ED current.

/t t%is point &ou %ave demonstrated t%at t%e lig%t output of a 8ED is a linear function of

t%e current in t%e device. ,e s%all use t%is fact to test t%e be%avior of anot%er $ind of

p%oto'detector t%e p%otoconductor. 6%e p%otoconductor resistance #ill be measured b& a

multi'meter in t%e resistance measuring4 mode. >epeat t%e 8ED'solar cell eperiments

replacing t%e solar cell #it% t%e p%otoconductor. Measure t%e resistance of t%e

p%otoconductor as a function of 8ED current t%at is t%e 8ED output. 6%e p%otocell s%ouldCust $iss4 t%e 8ED to ensure proper alignment.


78/122

9P%otoconductor "8ED

IIIIIIII0.0 IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII



IIIIIIII


79/122

9A

Plot t%e p%otoconductor resistance vs. "8ED.


80/122

9=

Plot t%e reciprocal of t%e p%otoconductor resistance vs "8ED.

et #ee$ (=! #e s%all eplore t%e use of a 8ED lig%t source a lig%t detector and its

circuitr& P Cunction p%otoconductor and p%ototransistor for@

t%e measurement of position transmission of information (bot% digital and analog!

and #%atever else &ou need to eplore for &our proCect


81/122

99

Acoustic De+ices Pro9ects

*or t%is proCect &ou #ill be provided #it% broadband spea$ers4 and narro# band

(ultrasonic! transducers. 6%e laborator& also #ill %ave acoustic #aveguides (P7) pipe!

and couplers bends and special slip fittings. Pipes of h and 1 meter in lengt% #ill be

available. elo# is t%e picture of t&pical devices available for t%is proCect.

*"+5>E 3=. /)O5S6") DE7")ES

"n t%e picture Ftop to bottomH #e s%o#@ 1 m pipe h m pipe m pipe slip fittings

#ideband transducer narro# band transducer :0j bend E 39. 7">65/8 ODE "S6>5ME6


82/122

9

*ind t%e best freuencies for operation.

,O>- SGEE6 GE>E@

est *reuencies Efficienc& (7out!

1stest f1@ IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

2nd

est f2@ IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

3rdest f3@ IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

o# measure t%e narro# band transducerQs response not using t%e m&D/ but rat%er t%elabQs digital signal generator and 6e$troni scope. ,e do t%is because t%e ultra'sonic

transducer operates above t%e freuenc& t%e m&D/ ode instrument can %andle.

Pea$ *reuenc& IIIIIIIIIIIIIIIIIIIIII

and ,idt% IIIIIIIIIIIIIIIIIIIIII

O6E@ t%e pea$ response occurs at about 2A -G;.


83/122

9:

5sing t%e best freuenc& for t%e broadband spea$ers measure t%e signal strengt% vs.

#aveguide lengt%.

,O>- SGEE6 GE>E@

Signal 8evel (7olts! Pipe 8engt%

Meter IIIIIIII

12Meter IIIIIIII

1 Meter IIIIIIIII

Plot t%e signal vs. distance (lengt%!


84/122

0

5sing t%e ultrasonic (narro# band! transducer measure t%e loss vs. distance (operate at

t%e pea$ freuenc&!.

*reuenc&@ IIIIIIIIIII

,O>- SGEE6 GE>E@

Signal 8evel (7olts! Pipe 8engt%

Meter IIIIIIII

12Meter IIIIIIII

1 Meter IIIIIIIII

Plot t%e signal vs. distance.


85/122

1

)ontinuing to use t%e ultra'transducers measure t%e effects of bending t%e pipe b&

inserting a :0j bend.

,O>- SGEE6 GE>E@

6%roug% aW Signal Strengt%


86/122

2

0ee1 : Introduction to Pro9ects "Continued#

('toElectronic Pro9ects

"n t%ese eperiments #e #ill investigate t%e use of a p%oto'source (8ED! and a p%oto

detector (p%otoconductor p%otodiode and p%ototransistor! as a position detector or as a

communications lin$.

/s a position detector t%e 8ED is ecited b& t%e continuous current in t%e circuit belo#@

*"+5>E 3. 8ED D>"7E> )">)5"6

*or communication t%e 8ED is energi;ed as in t%e circuit belo#@


87/122

3

*"+5>E 3:. 8ED /) D>"7E> )">)5"6

6%e 8ED output is detected b& t%e circuit belo#@

*"+5>E )">)5"6

6%e figure belo# s%o#s a t&pical eperimental setup. ote t%e polarit& of t%e

p%otoconductor is not important %o#ever t%e p%otodiode s%ould be reverse biased i.e.

cat%ode to L and t%e p%ototransistor collector to L volts.


88/122

/D PGO6O D"ODE >E)E"7E>

6%ree different detector devices are available@

1. P%otoconductor N t%e simplest of t%e devices but slo# in its results[2. P%otodiode N fast and reasonabl& sensitive[3. P%ototransistor N medium speed but ver& sensitive.

E;'eri)ent

)onnect t%e 8ED to t%e po#er suppl& and using a 1- o%m resistor set t%e voltage to

10 volts. 5sing t%e p%otodiode connect it as &our detector using t%e follo#ing circuit as

s%o#n@

*"+5>E


89/122

A

o%m resistor #it% a DMM. Place an obstacle bet#een t%e 8ED and t%e p%otodiode and

measure t%e voltage again. ote t%e results on t%e #or$s%eet.

,O>- SGEE6 GE>E@ >esistor si;e KIIIIIIIIIIIIIIII

7oltage #it% O obstacle@ IIIIIIIIIIIIIIIIIIIIII

7oltage #it% obstacle@ IIIIIIIIIIIIIIIIIIIIII

Suc% a c%ange could be used to note t%e presence of an obstruction. 6%is is in fact #%at is

used to stop garage doors from closing #%en somet%ing is in t%e #a& or supermar$et

c%ec$out stand conve&or belts. >eplace t%e p%otoconductor #it% a p%otodiode orp%ototransistor and repeat &our measurements. O6E@ it ma& be necessar& to replace t%e

10 - o%m resistor #it% a 1 - o%m resistor due to t%e increased sensitivit& of t%ese p%oto

devices.

,O>- SGEE6 GE>E@ >esistor si;e K IIIIIIIIIIIIIII

7oltage #it% O obstacle@ IIIIIIIIIIIIIIIIIIIIII

7oltage #it% obstacle@ IIIIIIIIIIIIIIIIIIIIII

6o demonstrate communications applications #e s%all connect t%e 8ED to a function

generator and our detector circuit using a p%otodiode connected to t%e oscilloscope. See

t%e follo#ing figure.


90/122

=

*"+5>E


91/122

9

?our detector output c%annel 1 s%ould be a suare #ave. Dra# t%e output noting t%e

timescale and amplitude.

,%at %appens #%en &ou graduall& reduce t%e function generator voltage`

,%& does t%e signal suddenl& go a#a&`


92/122

)%ange t%e function generator output to sine #aves. ,it% t%e function generator set to 10

volts amplitude dra# &our output #aveform. e sure to note amplitude and time.

o# use t%e offset adCustment of t%e function generator. Move it bot% positivel& and

negativel&. ote &our results@

)an &ou eplain #%at %appened`

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII


93/122

:

?ou #ill be provided #it% a P Darlington transistor #%ic% can be used in conCunction

#it% &our p%oto devices to control large loads. ?our p%oto detectors can control small

values of current i.e. micro'amperes of current to a fe# milliamperes. ?our transistor #illamplif& t%ese currents b& a factor of 1000. /ssuming t%e emitter of t%e transistor is

grounded and a current " flo#s in to t%e base of t%e transistor t%en if t%e collector is

biased %as a voltage positive #it% respect to ground t%en a collector current 1000 times

larger #ill flo#. 6%is #ill allo# &our p%oto device to control a large device suc% as t%e

motor.

See data s%eets in /ppendi D Darlington 6ransistor4.


94/122

:0

Acoustic De+ices Pro9ects

,e s%all measure t%e free space transmission of t%e ultrasonic devices. ?ou ma& conduct

eperiments as outlined belo# or ma$e use of t%e plastic parabolic reflectors. )onnect t%e

scope c%annel 2 to t%e sine output of t%e function generator. )onnect t%e signal out to t%e

narro# band transducer. 6%e second transducer receiver s%ould be connected to c%annel

1. Eac% transducer is connected to a s%ort piece of pipe as s%o#n belo#@

*"+5>E


95/122

:1

,O>- SGEE6 GE>E@

Distance (inc%es! Signal (volts N pea$ to pea$!

IIII04 IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII




IIII


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Plot &our results belo#@

Go# does t%e intensit& c%ange #it% distance i.e. rn`

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

Measure t%e angular pattern of &our transducer b& placing t%e t#o pipe ends about A4apart. Starting #it% t%e ends aligned measure t%e output as a function of lateral

displacement. See t%e figure belo#.


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*"+5>E - SGEE6 GE>E@

Displacement (inc%es! Signal (volts N pea$ to pea$!





IIII


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: D>"7E )">)5"6


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:

0ee1 2= Pro9ect De)onstration (ral and 0ritten .e'orts

On t%e last da& of t%e laborator& eac% student (or student group! #ill be reuired todeliver a proCect verbal and #ritten report. 6%e details of t%e reporting reuirements #ill

be given to &ou b& t%e At%#ee$ b& t%e 6eac%ing /ssistant.


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I0U1( A2$ IS3LA4 S5&6I%0

7ISSI3A'I&% LI!I'I%0 1(SIS'&18 9%&:

"t is good practice to reduce t%e voltage b& setting t%e nob (*igure /2! to ;ero #%en eit%er

starting tests or c%anging polarit&. 6%e polarit& selector labeled P (positive! or PP

(negative! applies eit%er positive or negative voltage on t%e collector terminal #it% respect

to t%e emitter terminal.

6%e resistor value is c%osen to limit t%e po#er. *or eample if 1- o%m is c%osen t%en no

more t%an 20 milliamperes can flo# and t%e maimum po#er dissipation possible in t%e

device occurs if %alf of t%e voltage 2072 is across t%e device and %alf across t%e series

limiting resistor. 6%erefore 10 m/ #ould flo# and t%e po#er dissipation 10 m/ 10 7 K

100 milli#atts.

et #e need to set t%e displa& current and voltage range.

In addition, please select the . ; 2. volt range only$ o %ot operate in . ; 2.. +

#ode Serious shocks can occur if the . ; 2.. + range is used$ & %&' US( I'


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I0U1( A*$ +(1'ICAL A% 5&1I


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/'$ SU00(S'( S(''I%0S

&1 5I05 :1I05'%(SS L(S A% 5I05 3&6(1( L(S

L(') 5I05 :1I05'%(SS L( 1I05') 5I05 3&6(1( L(

)urve 6racer settings for@

Gig% brig%tness 8EDs

Series resistor (A - o%ms!

7ertical sensitivit& (1 milliamperedivision!

Gori;ontal sensitivit& (1 7division!

Gig% po#ered suare 8EDs

Series resistor (A00 o%ms!7ertical sensitivit& (10 milliamperesdivision!

Gori;ontal sensitivit& (1 7division!

Solar cells (h7


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/'A

P%otodiodes (detectors! i.e. small signal devices

Series resistor (10 - o%ms!

7ertical sensitivit& (0.2 milliamperesdivision!Gori;ontal sensitivit& (0.1 7division!


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'1

APPENDI> - Analo! MultiMeters


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'2


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'3


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'


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'A


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'=


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)'1

APPENDI> C Di!ital MultiMeters


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)'2


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)'3


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)'


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)'A


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D'1

APPENDI> D Darlin!ton Transistor


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D'2


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D'3


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Documents

EE3 Laboratory Manual V1.8a - PDFCreator Soft Fonts