EE 240 Evaluation of Circuits Laboratorybode.ee.mnsu.edu/~paco/Lab.pdf · EE 240 Evaluation of Circuits Laboratory ... 9.6.1 Measuring Sine and Non-sinusoidalWaveform with ... the

EE240Evaluationof CircuitsLaboratory

MuhammadKhaliqJulio C. Mandojana

August31,2004

ii

Contents

1 Laboratory Safety 31.1 ElectricShock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.2 SafetyPrecautions . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3 Circuit Grounding. . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.4 Sourcesof Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.5 GeneralLaboratoryOperatingProcedure. . . . . . . . . . . . . . . . 6

2 Digital and Analog Multimeters 92.1 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.2 Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.3 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.3.1 ResistanceMeasurement. . . . . . . . . . . . . . . . . . . . 102.3.2 DC Measurements. . . . . . . . . . . . . . . . . . . . . . . 122.3.3 Ohm’sLaw . . . . . . . . . . . . . . . . . . . . . . . . . . . 122.3.4 ProtoboardConnections . . . . . . . . . . . . . . . . . . . . 132.3.5 VoltmeterInternalResistanceMeasurement. . . . . . . . . . 132.3.6 AmmeterInternalResistanceMeasurement. . . . . . . . . . 14

3 Resistive Cir cuits and Power 173.1 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173.2 Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173.3 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.3.1 ParallelResistanceCircuit . . . . . . . . . . . . . . . . . . . 183.3.2 SeriesandParallelResistanceCircuit . . . . . . . . . . . . . 193.3.3 ReferenceGround . . . . . . . . . . . . . . . . . . . . . . . 203.3.4 Ohm’sLaw Plot . . . . . . . . . . . . . . . . . . . . . . . . 21

4 WheatstoneBridge 234.1 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234.2 Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234.3 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234.4 ReadingAssignment . . . . . . . . . . . . . . . . . . . . . . . . . . 244.5 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

iii

iv CONTENTS

5 Divider Cir cuits and LEDs 295.1 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295.2 Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295.3 ReadingAssignment . . . . . . . . . . . . . . . . . . . . . . . . . . 305.4 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.4.1 CurrentDivider Circuit . . . . . . . . . . . . . . . . . . . . . 305.4.2 Light EmittingDiode(LED) . . . . . . . . . . . . . . . . . . 31

6 Equivalent Cir cuits 336.1 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336.2 Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336.3 ReadingAssignment . . . . . . . . . . . . . . . . . . . . . . . . . . 336.4 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

7 Superposition and Maximum Power Transfer 377.1 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377.2 Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377.3 ReadingAssignment . . . . . . . . . . . . . . . . . . . . . . . . . . 387.4 Pre-labAssignment. . . . . . . . . . . . . . . . . . . . . . . . . . . 387.5 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

8 Operational Amplifiers 418.1 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418.2 Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418.3 ReadingAssignment . . . . . . . . . . . . . . . . . . . . . . . . . . 418.4 Pre-labAssignment. . . . . . . . . . . . . . . . . . . . . . . . . . . 428.5 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

9 Oscilloscopesand Function Generators 459.1 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459.2 Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459.3 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469.4 Oscilloscope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469.5 FunctionGenerator . . . . . . . . . . . . . . . . . . . . . . . . . . . 479.6 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

9.6.1 MeasuringSineandNon-sinusoidalWaveformwith Oscilloscope489.6.2 MeasuringDC Voltagewith Oscilloscope . . . . . . . . . . . 48

10 Evaluation of Equivalent Cir cuits via SPI CE 5110.1 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5110.2 Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5110.3 Pre-labAssignment. . . . . . . . . . . . . . . . . . . . . . . . . . . 5110.4 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5210.5 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

CONTENTS 1

11 Measurementof Capacitanceand Resistance 5711.1 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5711.2 Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5711.3 ReadingAssignment . . . . . . . . . . . . . . . . . . . . . . . . . . 5811.4 Pre-labAssignment. . . . . . . . . . . . . . . . . . . . . . . . . . . 5811.5 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

12 Measurementof Inductanceand Resistance 6112.1 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6112.2 Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6112.3 ReadingAssignment . . . . . . . . . . . . . . . . . . . . . . . . . . 6212.4 Pre-labAssignment. . . . . . . . . . . . . . . . . . . . . . . . . . . 6212.5 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

13 Evaluation of RC and RL Cir cuits via SPI CE 6513.1 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6513.2 Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6513.3 Pre-LabAssignment . . . . . . . . . . . . . . . . . . . . . . . . . . 6513.4 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6513.5 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

A Laboratory Notebook 71

B Laboratory Reports 73

2 CONTENTS

Laboratory 1

Laboratory Safety

TheEE240-Evaluationof CircuitsLaboratorycourserequirethestudentsto build sim-plecircuits,makemeasurements,verify thetheory, comparetheresultswith simulatedvaluesobtainedfrom SPICE, andfinally diasssemblethe circuit. During the experi-ment,documentyourmeasurements,observations,any comments,circuit modificationin the Note Book, andlater on reportyou resultsin the LaboratoryReport. ImproveyourNoteBook entriesandLaboratoryReportwriting skills by thefeedbackyou willreceive from thelaboratoryinstructor. Thelaboratorysessionswill bethreehoursdu-ration,comepreparedfor the lab, readthetheoryrelatedto theexperiments,andplantheexperimentsto finish it in threehourssession.Theexperimentsaredesignedto bein synchronouswith the topicstaughtin thecourseEE 230-CircuitAnalysisI. Theremaybesomeoccasions,the lab experimentaheadof the topic coveredin thecourse.Thefollowing topicswill becoveredin thissection:

ElectricShock

LabSafetyPrecautions

Circuit Grounding

Sourcesof Errors

GeneralLaboratoryOperatingProcedure

1.1 Electric Shock

Electricshockis causedby an electriccurrentthroughthe humanbody. Theseveritydependson the currentthroughbody ratherthan voltage. The thresholdof electricshockcurrentis about1mA, which producesunpleasanttingling feeling. At 10mA ofelectriccurrentseveremusclepain occurs,andcurrentof 100mA to 200mA causesventricularfibrillation of heart,which is lethal. Voltageof 110V, which can cause160mAon a wetskin,will befatal.

3

4 LABORATORY 1. LABORATORY SAFETY

1.2 SafetyPrecautions Don’t work alonewhile workingon high voltage

Never leavehighvoltageunattended

Keeponehandin pocketwhile probinghighvoltageor dischargingcapacitor

All high voltageterminaltapedor insulatedto preventaccidentalcontact

After switchingoff powerdischargecapacitors

Don’t trustthecapacitoris discharges

Useshorteningbaracrosscapacitorsto keepit discharged

On electrolyticcapacitor, don’t put excessive voltageacross,anddon’t connectthemin reversepolarity

Useinsulatedtools. In caseof accidentalcontactthe insulatedtool will help topreventelectricshock

Shutoff power immediately, in casea personcomesin contactwith high volt-age.Donotattemptto removethepersonin contactwith highvoltage,unlessyouareinsulted.

Checkcurrentcarryingcapacityof the wire beforeusing for interconnectionsandconnectorswith insulatedshrouds.

Makesurethetestleadsareratedfor thetestvoltage

Makesurethelab instrumentsareconnectedto groundterminals

Useinstrumentswith threewire powercords.

Alwaysshutoff powerbeforetouchingwiresor connectors.

Alwayswearshoesandkeepshoesdry. Do not standon metalor wetfloors.

Neverhandleinstrumentswhenyourhandsarewet.

Alwaysmake theconnectionto thepointof highpotentialat thelaststep.

Set the currentlimited (but enoughto supply the circuit undertest)on powersuppliesto prevent too largecurrentsto flow. This will protectyou, the circuitandinstrumentsundertest.

Do notuseavery longcable(shortcableswill reducenoisepick upaswell) andneverhavecableslay on thegroundto preventtripping over it.

1.3. CIRCUIT GROUNDING 5

1.3 Cir cuit Grounding

Circuit groundingreducesthe noiseinterferencein the signal,which could producefalsemeasurements.Earthin consideredelectricallyneutral,becauseof its largeandequalnumberof positive andnegative charges. Thereforeearthcanbe consideredasreferencevoltageto measurethe testvoltage. ”A referenceof zerovolt is technicallyattributedto a well in which eithera rod having a lengthof at least8 feet is in contactwith thesoil directly or a suitablewire is beingconnectedto theEarththrougha plateof a conductingmaterialsurroundedby Carbonlayers”. In theschematicdiagramthegroundterminalin thereferenceterminalor earthis physicalconnected.

The mostcommonnoiseproblemencounteredin the complicatedelectronicsys-temsoriginatesfrom a lack of goodgroundingpractice.If morethana few pointsareusedfor groundconnections,differencesin potentialbetweenthereferencepointscancause”ground loops” phenomenon,which will causeerrorsin voltagereadings,(i.e.,the referencepointswould not be in the samelevel of zerovoltageany more)whichoftenexist in thegroundplaneto which thecircuitsareconnected.A goodsignof theexistenceof agroundloopor missingawell-groundedcircuit is thepresenceof a60Hznoisecomponentin theoutputsignal. Thegroundloop voltagecanbeeliminatedbyconnectingall groundpointsin thecircuit to only onepoint which is connectedto theearthground.Anothergoodpracticeis to useshortcables,which carrysmall signalsandkeepthemfixed. In addition,analoganddigital groundsshouldbegenerallykeptseparatedandconnectedtogetheronly at onesinglepoint.

The potentiallyfloating circuits cancauseseriousdangerfor the peoplewho areworking with them. Connectingthe referencepoint of the circuit to the Earthwouldeliminatetheshockhazards.

1.4 Sourcesof Err ors

Thelaboratoryexperienceis usuallya pleasantandinsightful experience.This is toolthat strengthensconceptslearnedin lectures.However, sometimesit is frustratingifthe circuit doesnot work, resultsareunexpected,andtroubleshootingof the circuitexperienceis not enoughto solve theproblem.Bestway to preventthis time consum-ing experienceis to follow goodlab practices,andprepareyourselfbeforedoing labexperiment.Thecommonsourcesof errorsin thelab thatleadto errorsin resultsare:

Impropergrounding.

Improperorganizationof connectionson theprotoboard.Useshortandstraightwires of differentcolor. The layout of the protobaordshouldfollow closethecircuit.

Lack of understandingof theequipmentbeingusedfor measurements.

Insufficientunderstandingof theinstructionsor theschematics.

Rushingthroughtheexperiment.


Never connecta power supply to the outputof a function generator. This willdamagethefunctiongenerator.

Whendoingcurrentor resistancemeasurementswith themultimeter, do not puta voltageover thecurrentor resistanceinput terminalof themultimeter.

Best of all, readinstructioncarefully, understandthe operationof equipmentusedin theexperiment,understandthetheorybehindtheexperiment,anddo thecalculationsbeforestartingtheexperiment.

Comepreparedwith a planto managethetime properly, sothatexperimentcanbefinishedwithin thelab session.

1.5 General Laboratory Operating Procedure

Following is thelist of operatingproceduresthatyouareexpectedto follow:

Readtheexperimentdirectionscarefullyprior to eachlab session.

Treatevery instrumentcarefully, asthey areveryexpensive.

Preparethelabbeforecomingto thelabsession,andmakelist of datato betakenduringexperiment.

Putall datain thelab notebook,andfollow theinstructionsfor laboratorynote-book.

Do not work in a groupof morethantwo studentsperbench,unlessauthorizedby lab instructorfor a groupof threestudents.

Collaborateanddiscussyour resultswith yourgroupmembers.

Observingsafetyprecautionsis importantwhile working in thelab

Do not bring food,drink or beveragesin thelab.

Learnthe instrumentbeingusingfor eachexperiment.Make sureevery aspectof theexperimentis clearfor you by readingtheinstructionscarefully.

Do groundingin your circuit properlyaccordingto whathasbeenmentionedinthecircuit groundingsection.

Keepthebreadboardcircuitry well organizedandwith thesamelay out asmen-tionedin thelab notefor eachexperiment.

Never connecta power supply to the outputof a function generator. This willdamagethefunctiongenerator.

Manageyour lab timeproperlydividedbetweentheexperiments.

Returnall components,wires,andprotoboardbackto their original location.

1.5. GENERALLABORATORY OPERATING PROCEDURE 7

If aninstrumentis malfunctioning,reportto thelab instructor

Beforeleaving lab,placethestoolsunderthelabbench.

Beforethelab, turnoff power to all equipmenton thebench.

Beforeleaving lab, turn off themainpower to thebench.

Leave your workplaceat leastascleanandtidy asyou foundit. Puteverythingbackin its properplace.


Laboratory 2

Digital and Analog Multimeters

In this lab wepresentthebasicsof digital andanalogmultimetersfor measuringresis-tance,voltage,andcurrent.

2.1 Objectives

Thepurposeof this lab is to learntheoperationof equipmenton theworkbenchwork-bench,andsomemethodsfor measuringphysicalquantitieswith digital andanalogmultimeter. Youwill learn:

Theprinciplesof measuringresistance

Resistancecolorcode,andpower rating

Measurevoltage(v), andcurrent(I)

Understandcommonsourcesof errorsin measuringresistance(R), voltage(V),andcurrent(I)

Connectionson protoboard,andfind its contactvertically, horizontally, IC con-nections,groundterminal,variablepowersupplyconnection

2.2 Equipment

Thefollowing equipmentis requiredfor this lab:

1. Digital multimeter

2. Analogmultimeter

3. DC PowerSupply

4. Resistors

9

10 LABORATORY 2. DIGITAL AND ANALOG MULTIMETERS

5. Protoboard

6. Connectingcablesandconnectingwires

2.3 Procedure

2.3.1 ResistanceMeasurement

1. Getresistancesfrom thebox in thelab: 500Ohm,1kOhm,500Kohm

2. Measurethe resistancewith digital multimeter(DMM) shown in Fig. 2.1, andanalogmultimeter(AMM) shown in Fig 2.2Recordthemeasuredvalues.

Figure2.1: Digital multimeter(Fluke867B)

2.3. PROCEDURE 11

Figure2.2: Analogmultimeter(Simpson)

3. Find resistancevalues(nominal)usingcolor code.Calculatethedifferencebe-tweennominalandmeasuredvalue. Calculatethepercentagedifference.Is thedifferencewithin thespecifiedtolerancevalue?Usetheformatof Table2.1.

4. Connectthefollowing circuitsshown in Fig. 2.3on theprotoboardandmeasuretheresistancebetweenthepointsindicatedin thecircuit. Do themeasuredvaluesagreewith calculatedvalues?

5. Measureresistanceof your bodyby holdingprobestightly betweenthumbandforefinger. Recordthevalueof bodyresistance.Consideringa current 100mAthroughthebodyquietdangerous.How muchvoltageacrossyour handswouldbelethal?

Resistance NominalValue(

) MeasuredValue(

) Difference(%) Tolerance(%)1234

Table2.1: Experimentalandnominalvaluesof resistance


DMM

DMM

1 kΩ 330

Ω

10 kΩ

1 kΩ

15 kΩ

1.5 kΩ

12 kΩ

A

B C

D

A

B

Figure2.3: Seriesandparallelresistors

2.3.2 DC Measurements

Thepower supplygenerateseitherconstantvoltageor a constantcurrent.Thevoltageon the power supply is controlledby a knob labeledas voltage,and the current iscontrolledby anotherknoblabeledascurrent.Thereis a currentlimiting circuit in thepowersupplythatwill not generatemorecurrentthanthelimiting value.

1. SettheDC powersupplyshown in Fig. 2.4to provide5V usingthemeteron thefront panelof power supply. Adjust themultimeterto measureDC voltage,andconnecttheleadsfor voltagemeasurement.

Figure2.4: Powersupply

2. MeasurethevoltageusingDMM andAMM

3. Make measurementsbetweenpositive (+) andnegative (-) terminals,andfrompositive (+) to commonandfrom negative(-) to common.

2.3.3 Ohm’s Law

1. Setup thecircuit shown in Fig. 2.5

2.3. PROCEDURE 13

2.2 kΩ2 V

I

Figure2.5: Ohm’s law

2. AdjustDMM for DC current,andtheleadssetfor currentmeasurement

3. Measurethecurrentflowing throughtheresistor, andverify themeasuredvalueagreewith Ohm’sLaw, i.e.

4. Reversethe DMM leads,andmeasurethe current. The valuemeasuredagreewith Ohm’sLaw or not?

2.3.4 Protoboard Connections

1. Usecontinuity settingon DMM, anddeterminethe connectionsof pins on theprotoboardshown in Fig. 2.6.Notethatpinsareconnected,horizontally, groundconnections,IC chip connectorpin, rowsof pin with noelectricalconnection.

2. Make a sketchof the protoboardshowing the pins connectionsdeterminedbyDMM.

3. Repeattheabovemeasurementwith AMM

2.3.5 Voltmeter Inter nal ResistanceMeasurement

Ideallya voltmeterhasaninfinite resistance,which is notphysicallypossible.In prac-tice,a voltmeterhasa high resistance,which canbemeasuredby thecircuit shown inFig. 2.7Thecurrentthroughthecircuit is givenby:

(2.1)

If representstheinternalresistanceof thevoltmeter, we canwrite

(2.2)

1. Measureresistancevaluewith DMM

2. Connectthecircuit shown in Fig. 2.7


Figure2.6: Protoboard

3. Adjust powersupplyto 10V, andmeasurethevoltagewith DMM. Don’t rely onthemeteron front panelof thesupply. Why?

4. Computetheinternalresistanceof thevoltmeterusingaboveequation.

2.3.6 Ammeter Inter nal ResistanceMeasurement

Ideally theinternalresistanceof anammeteris zero,but in practicetheammeterhasasmall resistance.Fromthecircuit shown in Fig. 2.8, the currentin the circuit is givenby Ohm’sLaw:

(2.3)

Then

!" (2.4)

1. Selecta smallresistance(100 # ) andmeasureits valuewith a DMM.

2. Setthepowersupplyto 5V andmeasurethevoltagewith a DMM.

3. Connectthecircuit shown in Fig. 2.8,andsettheDMM to measureDC current.

4. MeasurethecurrentusingaDMM asanammeter.

5. Calculate usingEq.(2.4).

2.3. PROCEDURE 15

10 V V

1 MΩ

Figure2.7: Measurementof a voltmeter’s internalresistance

5 V

100 Ω

A

Figure2.8: Measurementof anammeter’s internalresistance


Laboratory 3

Resistive Cir cuits and Power

This lab dealswith the evaluationof circuits with parallel resistance,series-parallelresistance,andtermgroundreference.Calculationsof powerrating,andtotalpowerofthecircuit will alsobeperformed.

3.1 Objectives Evaluateoperationof parallelresistance,andseries-parallelresistancecircuit.

Measurecurrentandvoltagesin parallelresistance,andseries-parallelresistancecircuit.

Measuretotal currentis thesumof branchcurrentsin parallelresistancecircuit.

Confirmbranchvoltagesareequalin parallelresistancecircuit.

Analysisof series-parallelcircuit mathematicallyandthroughexperiment.

Measurevoltagewith respectto referenceground.

Computevoltagedropacrossresistance.

Ohm’sLaw plot, andVoltagevs. Powerplot.

3.2 Equipment Digital Multimeter

AnalogMultimeter

DC PowerSupply

Resistors

Protoboard

17

18 LABORATORY 3. RESISTIVECIRCUITSAND POWER

Connectingcablesandconnectingwires

3.3 Procedure

3.3.1 Parallel ResistanceCir cuit

1. Measureandrecordactualvaluesof resistancesin the Table3.1. Connectthecircuit, without thepowersupply.

Component Value Measurement Voltage Current$&%$('$) $*,+ -/.0+ 12.3+Table3.1: Datatable

2. Measureandrecordtotal resistance54 of thecircuit in Fig. 3.1

12 V 1 kΩ

R1 R2 R3

1 kΩ 1 kΩ

Figure3.1: Parallelresistors

3. Setthepowersupplyoutputto 12V, andconnectto thecircuit in Fig. 3.1.

4. Measureandrecordvoltageacrosseachresistance,includingthesourcevoltage .

5. SettheDMM to currentfunction,andmeasurethecurrentin eachbranch.Youhave to removewiresandinserttheammeterin eachbranchto measurecurrent.

6. Measureandrecordcurrentin eachbranchin thecircuit.

7. Usingthemeasuredresistancesandvoltages,calculatethebranchcurrents.

8. Calculatethetotal resistanceseenby thesourceby usingmeasuredvalues.

9. Calculatethetotal resistanceusingthemeasuredvalueof and 6410. Comparethecalculatedandmeasuredvalues.

3.3. PROCEDURE 19

3.3.2 Seriesand Parallel ResistanceCir cuit

1. Measureandrecordactualvaluesof resistancein Figs.3.2and3.3.

12 V

R1

R4

R2 R3

2.2 k7

Ω

10 kΩ

4.7 kΩ 6.2 k8

Ω

+9

-

Figure3.2: Seriesandparallelresisitors

12 V

R1

R2

R3

1 kΩ

330 :

Ω

+;- 330

:Ω

R4

330 :

Ω

0< 0

<

Figure3.3: Seriesandparallelresisitors

2. Calculateall unknown valueslisted in Table 3.2 for circuits in Fig. 3.2 andFig. 3.3usingOhm’sLaw.

4 =?> @=BA =BC @=ED 4 6=BA 6=BCCalculatedMeasured

Table3.2: Applicationof Ohm’s law

3. Apply power to the circuits in Fig. 3.2 and Fig. 3.3, measureand recordallunknown listedin Table3.2

4. Whenmeasuringvoltageuseproperpolarity, andbreakthe circuit to measurecurrent.

5. Determinetotal power, andthepowerdissipatedin theresistances.


6. Given the power rating of the resistancesusedin the circuit shown in Figs 3.2and3.3, calculatethe maximumvoltagethat canbe appliedwithout exceedingthepower ratingof theseresistances.

3.3.3 ReferenceGround

1. Measurethevaluesof resistancesusedin thecircuit shown in Fig.3.4,andrecordthevalues.

2. Setup thecircuits in Fig. 3.4,notethedifferentreferencenodesin thetwo cir-cuits.

12 V

R1

R2 1 kΩ

330 F

Ω+G

-0H

AI

CJ

VK

A=?

VK

C=?

12 V

R1

R2 1 kΩ

330 F

Ω+G

-

0H

AI

B

VK

A=?

VB=?B

Figure3.4: Differentreferencenodes

3. Calculatethevoltagesacrosstheresistance,andrecordvoltagedifferenceacrosseachresistance.

Unknown value CalculatedValue MeasuredValue VoltageDifferenceL @LMN

N (reference) 0 0 N OP P@N

Unknown value CalculatedValue MeasuredValue VoltageDifference L L NN N@P

P (reference) 0 0 P QO

4. Setthepowersupplyto 12V, andmeasurethevoltageacrosseachresistancewithrespectto groundterminals.Recordthemeasuredvalues.

5. Comparemeasuredandcalculatedvalues.

3.3. PROCEDURE 21

6. Doesthecircuit’sreferencepointhaveany effectonthevoltagedifferenceacrossany of theresistances?Explainyouranswer.

3.3.4 Ohm’s Law Plot

1. Usingthecircuit shown in Fig. 3.5,measurecurrentasa functionof powersup-ply voltagefrom thecalculatedvalue-12V to +12V.

V1 kΩ

+

-

A

V

Figure3.5: Ohm’s law plot

2. Plot currentvsvoltage,andverify plot fits thedefinitionof Ohm’sLaw.

3. For eachsettingof powersupplyvoltage,calculatethepowerdissipatedor con-vertedto heatby resistors.

4. Plot voltagevs power. For this part of the experimentusea 100 # resistance.Considertheresultsin termsof Ohm’sLaw, doestheplot fit thedefinition?


Laboratory 4

WheatstoneBridge

In this lab, we analyzethe WheatstoneBridge Circuit, anduseit to measuresmallchangesin resistanceaccurately.

4.1 Objectives To understandtheoryof operationof resistivebridges.

To calculateunknown valuesof resistancesandvoltagewithin a bridgecircuit.

To measurevoltagesandcurrentsin bridgecircuits.

4.2 Equipment Digital Multimeter.

DC PowerSupply.

Resistors:10 # , 2.2k # , 2.7k # , 3.3k # , 6.2k # , andsix (6) 1 k # .

10 k # potentiometer.

Protoboard.

Connectingcablesandconnectingwires.

4.3 Intr oduction

Thesystemto be analyzedis the WheatstoneBridge circuit which hasbeenusedfornearlyacenturyin themeasurementof verysmallchanges,or differences,in thevalueof resistors.This in effecthasmaderesistancevariationaverypowerful tool for useinthemeasurementof environmentalproperties.Resistorscanbemadeto changetheir

23

24 LABORATORY 4. WHEATSTONEBRIDGE

value,or vary, in proportionto awidevarietyof physicalpropertiesin theenvironmentsurroundingthem. A large fraction of all measurementsmadein mechanicalengi-neeringutilize Wheatstonebridgesandresistivesensors.Straingaugesfor mechanicalstress,pressuresensors,torquesensors,airflow sensorsandmechanicalmotion andpositionsensorsall useresistivetransducers.Whatis veryimportanthereis thatthere-sistancechangeis usuallyverysmallcomparedto theabsolutevalueof theresistance?

4.4 ReadingAssignment

Chapter-3, pages70-79of thetextbook(ElectricCircuitsby Nillsson).

4.5 Procedure

1. Calculatethe valueof R in Figs. 4.1 and4.2, when 5SUTVOWOXO # andwhen S TYOZTYO&# .

R1

RxV[

o

A

B

10 V

+\-

1 kΩ

Figure4.1: Voltagedivider

2. Comparetheresultsfor theWheatstonebridgewith thevoltagedivider. Whichcircuit givesthe largestpercentagechangein R for 10 # changein resistance?Calculatethe percentagechange.Which circuit you will preferto measurethechangein resistance?Recordvaluesin Table4.1,andTable4.21.

L N LBNCalculatedMeasured

Table4.1: Voltagedividerdata

1By convention,thefirst subscriptdenotestheplusterminal,while thesecondsubscriptdenotestheminusterminal.Whenthevoltageis referredto thereferenceor groundterminal,weomit thesecondsubscript.

4.5. PROCEDURE 25

R1

RxV]

o

A^

B10 V

+_-

R2

R31 kΩ

1 kΩ

1 kΩ

Figure4.2: Bridgecircuit

3. Hookup thecircuit shown Fig. 4.1,andmeasureactualresistancevaluesusingaDMM, andrecordthemin yournotebook.

4. Switchon thepower supplyto 10 V, andmeasurevoltage R for `S aTYOXOXO`# .Repeatfor `SbcTVOZTYOd#

5. By how muchdoesthevoltage R changewhenthe1000 # resistorchangesto1010 # .

6. Built circuit shown in Fig. 4.2, and measureactual resistancevaluesusing aDMM, andrecordthemin yournotebook.

7. Switch on the power supply to 10 V, and measurethe voltage R for S TVOXOWO&# . Repeatfor `ef TYOZTYO&# . Recordvaluesin Table4.2

L N LBNCalculatedMeasured

Table4.2: Bridgedata

8. By how muchdoesthevoltage R changewhenthe1000 # resistorchangesto1010 # .

9. Commenton your result, i.e. how accuratelycanyou measurethe changeinoutputvoltage(aspercentageof outputvoltageR ) usingthevoltagedividerandWheatstonebridge.Discusstheresults.

10. Hookup circuit shown in Fig. 4.3.Measureandrecordtheresistances.

11. Do notapplypower. Notethevariableresistance(potentiometer)hasbeenplacedin thebridge.Whichpoint is at ahigherpotentialA or B?


R1

RxVg

o

Ah

B12 V

+i-

R2

R310 kΩ

2.2 kj

Ω

2.2 kj

Ω

10 kΩ


12. Apply DC power. Monitor voltagebetweenpointsA andB, LBN with a DMM,while adjustingthepotentiometer`S until LBN is ascloseto zeroaspossible.

13. Removethepotentiometer, andmeasureits resistance2. Recordtheresultin yournotebook.Recordvaluesin Table4.3.

14. Calculatecurrent k=Bl andvoltage =Bl for the load resistance5m shown in theFig. 4.4.

R1

R4Vo

12 V

+n-

R2

R32.7 kΩ

6.2 ko

Ω

3.3 kp

Ω

2.2 kΩ

R5

10 kΩ


15. Hook up thecircuit shown in Fig. 4.4. Measuretheresistanceandrecordvaluesin thenotebook.

16. Apply DC powerto thecircuit in Fig. 4.4,andmeasure = l and = l . Recordthevaluesin Table4.4andin thenotebook

2 q?rtsu CYv u Au >

4.5. PROCEDURE 27

`w 5x SNominal CalculatedMeasured Measured


6=Bl =BlCalculatedMeasured



Laboratory 5

Divider Cir cuits and LEDs

In this lab, we analyzecurrentdivider circuitsandcurrent-voltage(IV) characteristicsof light emittingdiode(LED).

5.1 Objectives To understandthetheoryof currentdividercircuits.

To calculatecurrentsin differentbranchesof thecurrentdividercircuit.

To measurecurrentsto verify calculatedvaluesfor thecurrentdividercircuit.

To understandtheoperationof thelight emittingdiode(LED).

To measureIV-characteristicsof a LED, andfind its turn-onvoltage.

To usecurrentandvoltagemeasurementtechniqueslearnedin previousexperi-ments.

To applyKVL andKCL.

5.2 Equipment Digital Multimeter(DMM)

DC PowerSupply

Resistors:470 # , 1 k # , and10 k # Light emittingdiode(LED)

Protoboard

Connectingcablesandconnectingwires

29

30 LABORATORY 5. DIVIDER CIRCUITSAND LEDS


Pages72-73of thetextbook,ElectricCircuitsby Nillsson.Review Lab. 2.

5.4 Procedure

5.4.1 Curr ent Divider Cir cuit

1. Obtain resistances and 5w of 10 k # value. Measurethe resistancevaluesusinga DMM asanohmmeter.

2. Hook up thecircuit shown in Fig. 5.1

R1=10 k

V1

+

-

R2 R3

10 kΩ 470 Ω

Figure5.1: Currentdivider

3. Setthepower supplyto 12V. UseDMM to measuretheDC voltage;don’t relyon thefront paneldisplayof thepowersupply.

4. Using a DMM asa voltmeter, measurevoltageacrossthe 10 k # resistor, andacrossresistors and w . Recordthe valuesandverify Kirchhoff ’s voltagelaw (KVL).

5. Using a DMM as an ammeter, measurethe current throughthe 12-V source.Rememberyou have to breakthe circuit, andinsertthe ammeterin serieswith12-V source.

6. Measurethecurrentthrough and `w .7. Verify Kirchhoff ’scurrentlaw (KCL)

8. Verify currentdividercircuit calculations.

9. Examinethe accuracy of voltagemeasurement;considerthe internalresistanceof thevoltmetermeasuredin Laboratory2.

5.4. PROCEDURE 31

10. Examinetheaccuracy of ammetermeasurement;considertheinternalresistanceof ammetermeasuredin Laboratory2.

5.4.2 Light Emitting Diode (LED)

A light emittingdiodeis anonlineardevice. WhenanLED is forwardbiased(i.e. largeleadconnectedto thepositive terminalandthenegative leadconnectedto thenegativeterminal),exhibits low resistance.Currentincreaseswith the appliedvoltage,whenthe voltageacrossthe LED is greateror equalto the turn-onvoltage. At the turn-onvoltage y3z , theLED will glow. TheLED will glow around1.49V. In this partof theexperiment,current(I) vs. voltage(V) characteristicsof theLED will bemeasuredandplotted.

1. Constructthe circuit shown in Figure5.2. Measurethe resistancebeforecon-nectingin thecircuit.

V

1

+|

-

R4 1 kΩ

+|

-

V+|-

I+|-

LED

LED

Figure5.2: LED circuit

2. Turn on DC power supplyandvary thevoltagefrom -3V to 2V in stepof 0.5V.Measurethechangein voltagewith DMM usedasvoltmeter. Also monitor thecurrent throughthe LED at every stepof appliedDC voltage. Remembertobreakthecircuit to put DMM asanammeterin serieswith LED.

3. Make a graph of I-V Characteristics. Use software to plot I vs. V graph.No handdrawn graphwill beaccepted.A typical IV-Characteristicsof a diodeis shown in Fig. 5.3

4. Findon resistanceof theLED from IV-characteristics(I vs. V plot)

5. Verify KVL for theLED? What typeof modificationswill berequiredfor LEDcircuit to verify KVL?

6. Whatdid younoticein IV-characteristicsof LED?Is it linear?Whathappensfornegativevoltage?Whatis thevoltageat whichLED startsto glow, i.e., y z

32 LABORATORY 5. DIVIDER CIRCUITSAND LEDS

Figure5.3: Typical IV-characteristicof adiode(Takenfrfom MicroelectronicsCircuitsby Sedra& Smith)

Laboratory 6

Equivalent Cir cuits

In this laboratorywewill useThevenin’s theoremto analyzecircuits.

6.1 Objectives To understandtheconceptof Thevenin’ andSuperpositiontheorems.

To find anequivalentcircuit usingThevenin’stheorem.

To replacethe circuit by its Thevenin’s equivalentandmeasureits voltageandcurrent

Prove theequivalency of a network of severalresistorsto theThevenin’scircuitby comparingtheresultsof variousresistors

Draw Norton’sequivalentcircuit

6.2 Equipment Digital Multimeter(DMM).

DC PowerSupply.

Resistors.

Potentiometer5 k # .

Protoboard.



Pages141-148of thetextbook,ElectricCircuitsby Nillsson.

33

34 LABORATORY 6. EQUIVALENT CIRCUITS

6.4 Procedure

1. Measuretheresistanceshown in Fig. 6.1 by usinga DMM in Ohmmetermode,andrecordthemeasuredvaluesin yournotebook.

2. Calculatethe load voltage (i.e. 6~ ) for eachof the load resistances5Z # , O# , andX O# . Recordthe calculatedvaluesin your notebook.

12 V

+

-

R1

2 kΩ

R2

R3 RL

2 kΩ 2 kΩ

a

b

Figure6.1: Circuit to bereplacedby Theveninequivalent

3. Hook up the circuit shown in Fig. 6.1, andconnectto DC supply. Make sureyouhavemeasuredthevoltagewith DMM in voltmetermode.Don’t rely on thevoltageindicatedonthepanelof DC powersupply. Recordthemeasuredvoltagein yournotebook.

4. Connectthe one load resistancesat a time andmeasureload voltagefor eachresistance.Recordthe measuredvaluesin the notebook.The load resistancesare 5 Z 5 # , O&# .

5. Remove the loadresistancefrom point terminal’a’ and’b’. Calculatetheopencircuit voltagebetweenterminals’a’ and ’b’. This is the opencircuit voltageknown asTheveninVoltage 4 for the circuit. Recordthe Theveninvoltagevaluein thenotebook.

6. MeasuretheactualTheveninvoltageandrecordin thenotebook.

7. Calculatetheresistancebetweenterminal’a’ and’b’, which is Theveninequiv-alentresistance`4 . Recordin thenotebook.

8. DisconnecttheDC powersupply, andreplaceit with ashortusingajumperwire.Thenmeasuretheresistancebetweenterminal’a’ and’b’, which is themeasuredvalueof Thevenin’sresistance 4 . Recordin thenotebook.

9. Draw theTheveninequivalentcircuit in thenotebook.

6.4. PROCEDURE 35

10. For the equivalentcircuit drawn in step9, connectthe load resistances`5 # , T # , /O# oneat a time,andcalculatethevoltageacrosseachresitor(usevoltagedividercalculations).Recordvaluesin yournotebook.

11. Hook up thecircuit drawn in step9. Usea 5 k # potentiometerto representtheThevenin resistance.Set the potentiometerfor the resistancein the equivalentcircuit drawn in step9. Adjust thevoltagesourcefor theTheveninvoltage.Placeeachloadresistance` ` # , T # , O`# oneat a time on thecircuit andmeasurethevoltage.Recordthemeasuredvoltagesin thenotebook.

12. Remove the load resistancefrom the Theveninequivalentcircuit. Measuretheopencircuit voltagewith no load, which is 4 , and measurethe settingonpotentiometer, whichwill be 4 .

13. Hookup thecircuit shown in Fig. 6.2,andrepeatsteps4 to 9.

6 V

+

-

R1

RL

3 kΩ

a

b

V1

Figure6.2: Equivalentcircuit

14. Comparetheresultsof thetwo circuits,andcommenton your results.

15. Find the Norton’s equivalentfor the circuits in Figs.6.1 and6.2. Comparethetwo Norton’sEquivalentcircuits.

36 LABORATORY 6. EQUIVALENT CIRCUITS

Laboratory 7

Superposition and MaximumPower Transfer

We will analyzea circuit using the principle of superpositionand maximumpowertransfertheorem.

7.1 Objectives Understandtheprincipleof superposition.

Analyzethecircuit usingsuperposition.

Constructacircuit with two voltagesources,solvefor currentsandvoltages,andverify calculationswith measurements.

Constructamodelof avoltagesource.

Determinethe maximumpower obtainablefrom a voltagesourceof known in-ternalresistance.

Determinethesignificanceof internalresistanceof a voltagesource.


DC PowerSupply.

Resistors.

Protoboard.


37

38 LABORATORY 7. SUPERPOSITIONAND MAXIMUM POWER TRANSFER


Pages149-156of thetextbook,ElectricCircuitsby Nillsson.MaximumPower TransferTheorem:Theamountof power any sourcecansupply

to a load is limited by the internalresistanceof thesourceandwill beat a maximumvaluewhentheloadresistanceis equalto theinternalresistanceof thesource.

7.4 Pre-labAssignment

Completethecalculationsandcircuit analysisof thelab beforecomingto thelab ses-sion. Recordyour calculatedvaluesin thenotebookin tabulatedform. Leave spaceinthetableto enterthemeasuredvalues.

7.5 Procedure

1. Considercircuit shown in Fig. 7.1. Measurethe valuesof the resistancesandrecordin your notebook.UsingSuperpositioncalculatethevoltageacrosseachresistanceandthecurrentthrougheachresistance.Recordthecalculatedvaluesin yournotebook.Recordthecalculationsin a tablein thenotebook.

10 V

+

-

R1

4.7 kΩ

a

b

V1

12 V

V2 +

-

c

d

R3

R2

10 kΩ

6.2 kΩ

Figure7.1: Circuit to beanalyzedusingsuperposition

2. Hook up circuit shown in Fig. 7.1, and connectthe two DC power supplies.Rememberto measurethe DC voltageof the supplieswith DMM in voltmetermode.Don’t rely on thevoltagesshown on DC powersupplypanel.

3. Measurethevoltageacrosseachresistanceandrecordin yournotebook.

4. Connectthecircuit shown in Fig. 7.2

7.5. PROCEDURE 39

10 V

+

-

R1

4.7 kΩ

a

b

V1

c

d

R3

R2

10 kΩ

6.2 kΩ

jumperwire

Figure7.2: Source2 is turnedoff

5. Notethatthe12-V sourceis replacedby ashort(jumperwire) betweenpointsCandD. Calculatethetotal resistanceseenby 10V powersupply. Removethe10-V power supply, andmeasuretheresistancebetweenpointsA andB. Comparethemeasuredandcalculatedvalues.Calculatethecurrentsandvoltagesin eachbranchof thecircuit whenthe10-V powersupplyis connectedto thecircuit.

6. Reconnectthe10-V powersupply, andmeasurethecurrentandvoltagesof eachbranchof thecircuit. Recordthemeasurements.

7. Connectthe circuit shown in Fig. 7.3, andrepeatsteps4 to 6. Make surethe10-V supplyis replacedby a jumperwire in thiscase.

R1

4.7 kΩ

a

b

12 V

V2 +

-

c

d

R3

R2

10 kΩ

6.2 kΩ

jumperwire

Figure7.3: Source1 is turnedoff

8. Fromabovedata,verify theprincipleof superposition.

9. Connectthe circuit shown in Figure 7.4. Set equalto 10 V and measureresistancesin thecircuit. Use `cTVOWOd# , XWOd# , /O&# , XWO&# , T # , T & # ,

40 LABORATORY 7. SUPERPOSITIONAND MAXIMUM POWER TRANSFER

# , d # , TVO # . Useone ` valueat a time for measurements.

R1

RL

1 kΩ

+

-

Vs V

Figure7.4: Variableloadcircuit

10. Switch on the DC power supply , with no connected(no load),measuretheunloadedvoltage.Recordmeasuredvaluein thenotebook.

11. Connecteachof the load resistancegiven in step9 oneby one. Measurethevoltageacrosseach (loadresistance)andrecordin thenotebook.

12. Calculatethepower dissipatedby eachloadresistance5 usingmeasuredloadvoltagevalues.

13. Plot power dissipatedin eachload resistanceRL vs. the load resistanceRLvalues.(No handdrawn graphswill beacceptedwith thereport). Find themax-imum power dissipatedin the loadresistance` from thegraph.Comparethemaximumpowervalueobtainedfrom thedatawith thecalculations.Whatis themaximumpowerobservedin thisexperiment?

14. What is the ratio of voltageacrossthe load resistance5 that dissipatedthemaximumpowerandtheDC powersupply voltagemeasuredin step10?

15. Fromthedataverify themaximumpower transfertheorem.

Laboratory 8

Operational Amplifiers

We will evaluatetheDC characteristicsof operationalamplifierin differentconfigura-tions.

8.1 Objectives To learntheDC operationof anoperationalamplifier.

To analyzetheinvertingoperationalamplifiercircuit.

To analyzethenon-invertingoperationalamplifiercircuit.

To analyzethesummingoperationalamplifiercircuit.


741OperationalAmplifier.

DC PowerSupply.

Resistors.

Protoboard.



Chapter-5 of thetextbook,ElectricCircuitsby Nillsson.

41

42 LABORATORY 8. OPERATIONAL AMPLIFIERS


Completethecalculationsandcircuit analysisof thelab beforecomingto thelab ses-sion. Recordyour calculatedvaluesin thenotebookin tabulatedform. Leave spaceinthetablesto enterthemeasuredvalues.

8.5 Procedure

1. The OperationalAmplifier (Op. Amp) to be usedin this lab is the 741,whichcomesin a DIP (dual in-line package)packageshown in Fig. 8.1. Spendsometime to understandthepin connectionof the741. UseFig 8.1 to relatepin con-nectionswith thatof the opampsymbol. Make sureyou know the pin connec-tionsbeforeconnectingthedeviceinto thecircuit. In caseyouarenotsureaboutthepin connections,asklab instructorto helpyou identify thepin connections.Pin1, and5 areusedfor nulling theoffsetvoltage,this functionwill notbeusedin this lab. Pin 8 is not connected(NC) to theinternalcircuit of theopamp.

1

2

3

4

87

6

5

offset null

inverting input

non-invertinginput

V-

nc

V+

output

offset null

+

-

V+

V -

3

2

7

4

6

Figure8.1: Operationalamplifier

2. Fig. 8.2 shows the connectionsfor the DC power supplies+VCC = +15V and-VCC = -15V. Rememberto measurevoltagewith a DMM in voltmetermode.Don’t rely on thepowersupplypanelindicator.

3. Designthe inverting operationalamplifier shown in Fig. 8.3 to provide gains,RYX@ of -100,-10,and-1 usingtheresistorvaluesof TVOWO # , TYO # , T # , andTYOXO# . Measuretheseresistanceswith DMM in ohmmetermodeandrecordthevaluesin thenotebook.

4. Measuretheoutputvoltagefor input voltageof 0.0V, +0.1V, +1V. UseDMM involtmetermodeto measuretheinputandoutputvoltages.

5. Plot output voltage R vs. input voltage , and plot gain vs. input voltage.Explainyour results.No handdrawn graphwill beaccepted.

6. Repeatstep3 through6 for the non-inverting operationalamplifier shown inFig. 8.4 for gainsof +10 and+1. Combinethe given resistancesto obtainthespecifiedgains.

8.5. PROCEDURE 43

+

-

V+

V-

3

2

7

4

6

LM 741

15 V

15 V

+

+

-

-

V1

V2

Vo

Figure8.2: Biasingof a typical op amp

+ -

V+

V-

3¡

2¢

7£

4¤

6¥

LM 741

+

+

-

-

VCC

V¦

o

V¦

CC

Rf

0§

Ri

Figure8.3: Invertingamplifier

7. Designa summingamplifierthathasa gainof -10 for input E , anda gainof -5for inputs w and x (assumew¨x ). The circuit for summingamplifier isshown in Fig. 8.5.Write theexpressionfor theoutputvoltage.Vo.

8. Build the circuit shown in Fig. 8.5. Rememberto measureall resistancesandDC power supplyvoltage+V P©P = +15 V, -V P©P = -15 V, andrecordthevaluesin thenotebook.

9. Switch on the DC power supply, andverify the designdonein step8, andtheexpressionfor outputvoltageVo. Rememberto selectareasonablevalueof inputvoltage which will keeptheoutput R in the linear region of theoperationalamplifier.

44 LABORATORY 8. OPERATIONAL AMPLIFIERS

+ª-

V« +V« -

3¬

2

7®

4¯

6°

LM 741±

+ª

+ª

-

-

V«

CC

Vo

V«

CC

R²

f

0³

R²

i

Figure8.4: Non-invertingamplifier

+ª-

V« +V-

3¬

2

7

4¯

6°

LM 741

+ª

+ª

-

-

VCC

V«

o

V«

CC

Rf

0³

R1

R2

R²

3

V1

V«

2

V«

3

Figure8.5: Addercircuit

Laboratory 9

Oscilloscopesand FunctionGenerators

This is anintroductionto theoscilloscopeandthefunctiongenerator. We will performmeasurementsof voltage,time,andfrequency of time-varyingsignal.

9.1 Objectives To understandthebasicoperationof theoscilloscope,andits controls.

To displayDC andAC waveformson theoscilloscope.

To measuretime-varyingsignalswith anoscilloscope.

To measuretheperiodandcalculatethefrequency of time-varyingvoltageswiththeoscilloscope.

To understandtheoperationof thefunctiongeneratorandits controls.


Oscilloscope.

FunctionGenerator.

DC PowerSupply.

Protoboard.


45

46 LABORATORY 9. OSCILLOSCOPESAND FUNCTIONGENERATORS

9.3 Intr oduction

Whenvoltagesandcurrentsin anelectriccircuit becometime-varying,it is frequentlydesirableto beableto graphicallydisplaythemasafunctionof time. In otherwordswewould like to observe,andrecordplotsof, circuit voltagesandcurrentsasafunctionoftime. If thetime variationoccursbriefly in oneshorttime interval, thesignalis called”transient”.For signalsthatare”periodic” in time (regularly repetitive),wewould liketo measurethefrequency or repetitiontime(theperiod)andshapeof thefunction.Thelab instrumentfor suchtime resolvedmeasurementsis known asanoscilloscope.Ac-tually it is nothingmorethana very simpleblack andwhite TV, or monitor, screenwith a single(or at mostseveral)voltagecontrolledrasterline. In this laboratoryexer-ciseyouwill familiarizeyourselfwith useof theoscilloscopefor timeresolvedvoltagemeasurements,andthe function of the front panelcontrolson the instrument.At thesametimeyouwill observethethreetime-varyingfunctionsprovidedby thelaboratoryfunction generator, namelysinewave, squarewave, triangularwave. The instrumentmanualis locatedon top of your labbench.

9.4 Oscilloscope

1. SweepSensitivity: thehorizontaltime axiscrossesthescreenfrom left to right,seeFig. 9.1. Thetime SCALE in fractionalsecondspercentimeter(or division)acrossthescreenis setby thehorizontal”sweeptime” controlknob. Thespotoflight thatproducesthedisplaycansweepacrossthescreenonetimeonly (single-shot)or repetitively at a fixed rate(continuous),assetby the ”trigger” controlswitches.

2. Vertical Sensitivity: The oscilloscopeallows one to display two independentVOLTAGE signalssimultaneously, on channel1 (CH1) andchannel2 (CH2). Theamplitudeof the displayedtime functionsis controlledby the ”vertical sensi-tivity” controlknobsfor eachchannel.Therangeof signalamplitudesthatcanbeselectedfor displaygoesfrom milli volts to tensof volts perverticaldivision(centimeter).Eachchannelhasa couplingcontrol switch thateither;(a) shortstheinput to groundinternally, (b) placesa largecapacitorin serieswith theinputtherebyblockingany DC voltagefrom the input (AC coupling),or (c) DC cou-pling that is a directconnectionfrom input terminalto oscilloscope.A verticalMODE control switch allows oneto display; (a) only CH 1, (b) only CH 2, (c)first CH 1 thenCH 2, alternatingcontinuously(NEVER USETHIS MODE), (d)both channelssimultaneouslydisplayed(choppedmode),(e) channelA inputADDED to CH 2 input andthesumdisplayed.A switchon CH 2 input caninvertthevoltagesignalbeforedisplayingit.

3. TracePosition:Thestartingpoint on-screenfor thehorizontalaxis(t = 0 point)is setby the horizontalpositioncontrol knob. The relative vertical positionoftheV = 0 axisis adjustedwith theverticalpositioncontrolknoboneachverticalchannel.

9.5. FUNCTIONGENERATOR 47

Figure9.1: Oscilloscope

4. Brightnessandfocus: Both are independentlyadjustable.The traceshouldbejust barelyvisible on thescreenfor bestmeasurementresolution.Neverallow abright spotto traceslowly acrossthescreen.

9.5 Function Generator

Thefunctiongenerator(FG) canprovidemany differentsortsof repetitiveandtransienttimefunctions.Wewill only beinterestedin thethreeprimaryperiodicfunctions;sinewave, squarewave and triangularwave. The function switch selectsbetweenthem,seeFig. 9.2. A DC offsetswitchallows oneto insertan internalDC voltagesourceinserieswith the time-varying voltage. Thereis one BNC coaxoutput terminalon the

Figure9.2: Functiongenerator

unit. A trigger outputsignalis alsoavailablewhich is a very shortpulseoccurringafew nanosecondsbeforethefunctiongeneratoroutputpassesthrough”0” volts.

1. Thesignalfrequency is setby decadepush-buttonswitchesanda continuouslyadjustablecontrolknobwithin thedecaderange.Frequency is givenin Hz.


2. PeakAmplitudeof theperiodicsignalis setby acontinuouslyadjustable”0 - 30V” controlknob. Theamplitudecanbefurtheradjusteddownwardby power often”attenuator”push-buttonswitches,or by a rotarydecadeswitchknob;-20db, -40db,-60db,etc.

9.6 Procedure

9.6.1 Measuring Sineand Non-sinusoidalWaveform with Oscillo-scope

1. Connecta BNC cablefrom theFG outputto theCH2 of oscilloscopeinput.

2. Connectanothercablefrom theFG triggeroutput(locatedat thebackof theFG)to theoscilloscopetriggerinput.

3. Setup the FG for trianglewave, at 20.0KHz, and0.3 V peakoutput. Do notproceedunlessyou aresureit is correctlysetup.

4. Adjust thescopecontrolsto display2-3 completetrianglewave cycleswith am-plitude nearlyfilling the screen.Setthe trigger control switch to ”automatic”.UsechopmodeandgroundCH1 input, ”0V”. Recordall relevant settingsonbothFG andoscilloscope.

5. Recordaccuratelythefunctionyouseeon thescreen.Measuretheperiodof thetrianglewave on the screenandcheckit againstfrequency measuredwith the(yellow) Fluke multimeter. Measurethe+ and- peakvaluesof the functiononscreen.Checkthezerovolt tracepositionon screenby groundinginput.

6. Now changeALL of the settingson the oscilloscopeto seehow they affect thedisplay. Record.

7. Returnthescopeto theconditionsin step-3.SwitchtheFG to sinewaveandthensquarewave repeatingstep-4in eachcase.Repeatstep-5for the squarewave.Seeaneasyway to measurepeakvoltage?

8. SettheoscilloscopeCH 2 verticalsensitivity to 1.V /cm andsweepto 20 microseconds/cm.Now changemostof thesettingson the FG to seehow they affectthedisplay. Usea sinewaveformonly.

9.6.2 Measuring DC Voltagewith Oscilloscope

1. Establishthegroundreferencefor CH 1 andCH 2 by settingthe input couplingswitch to ground(GND). Usevertical POS switch for channel1 and2 to placethetraceatdifferentlevel on thescreenof theoscilloscope.

2. Move input couplingswitchto DC

9.6. PROCEDURE 49

3. SwitchonDC thepowersupplyandmeasure2 V with a DMM in voltmetermode.Connectthe2-V power supplyto the input of theoscilloscopeusingtheproperscopeprobe. The traceon the screenwill shift with respectto the referenceestablishedin step1. Themagnitudeof thevoltageis equalto (=Volts/Div x No.of divisions).Reversethepolarityof theDC voltage,describewhatyousee?


Laboratory 10

Evaluation of EquivalentCir cuits via SPI CE

Analysisof circuits consistingof independentanddependentsources,and its verifi-cationby simulationusingPSPICE. Verificationof Thevenin’s,Norton’s theoremandmaximumpower transfertheoremusingPSPICE.

10.1 Objectives Understandthebasiccommandsfor differenttypeof dependentsources.

Verify thehandcalculationwith PSPICE for acircuit containingindependentanddependentsources.

Verify Thevenin’stheoremandmaximumpower transfertheoremusingPSPICE.

Verify Norton’s theoremandmaximumpower transfertheoremusingPSPICE.

Comparethecurrentsource(Norton’s)andvoltagesource(Thevenin’s)theoremanalysis.

10.2 Equipment PCwith studentversionof PSPICE or similar.

10.3 Pre-lab Assignment

Chapters2 and4 of therecommendedbook,SPICE(3rdEdition),by PaulW. Tuinenga

51

52 LABORATORY 10. EVALUATION OF EQUIVALENT CIRCUITSVIA SPICE

10.4 Intr oduction

Following is thesummaryof commandsthatyouwill needto usePSPICE for analyzingthecircuitslab. Thedesignation[...] meansanoptionalitem; ´ ....µ is a requireditem

VCVS: ThesyntaxisE[name] ¶ +node·¶ -node·¶ +controlnode-controlnode·¶ gain·Example10.1 : E 2 3 1 0 5 (i.e. a VCVSbetweennode2 and3, dependenton voltagebetweennodes1 and0. VoltageE will be5 timesvoltage betweennode1 and0, i.e.,

-%¹¸).

For thecircuit in Fig. 10.1,theVCVSwouldbedescribedbythefollowingline in theinputfile:

E 3 0 2 0 2

10 V

R1

250 Ω

R2

R3

RL

100 kΩ

40 Ω

1 Ω+

-

Vx

+-

2 Vx

0

1 2 3 4

E

Figure10.1:Voltage-controlledvoltagesource

CCCS: ThesyntaxisF[name]¶ +node·¶ -node·t¶ controllingV device name·t¶ gain·Example10.2 : F 4 2 VA 50 (i.e. a CCCSbetweennode4 and2 with current throughthesourcefromnode4 to node2. Thecurrentis dependenton thecurrentthroughsourceVA,havinga gain factorof 50.) For thecircuit in Fig. 10.2,theCCCSwouldbedescribedby thefollowing line in theinput file:

Vo 4 2 0VF 3 0 Vo -3

Thepolarity of thedummyvoltage sourcedependson thedirectionof currentcontrollingthedependentsource.

VCCS: ThesyntaxisG[name] ¶ +node·t¶ -node·¶ +controlnode-controlnode·¶ transconductance·

10.4. INTRODUCTION 53

35 Vº

R1

100 Ω

R2

R3

R5200 »

Ω 500 Ω

0

1 2»

3º

4 3 Iº

x

Ix

500 Ω

0 v

500 ΩR4F

Figure10.2:Current-controlledcurrentsource

Example10.3 :G 5 1 2 0 0.05(i.e. a VCCSbetweennode5 and1, dependentonvoltagebetweennodes2 and0. Thetransconductancevalueis 0.05.)For thecircuit in Fig. 10.3,VCCSwouldbedescribedby thefollowing line in theinputfile:

G 3 0 2 0 0.02

12 V

R1

300 Ω

R2 R4900 Ω 200 Ω

0

1 2 3

200 ΩR3

+

-

Vx

0.02Vx

G

Figure10.3:voltage-controlledcurrentsource

CCVS: ThesyntaxisH[name] ¶ +node·¶ -node·¶ +controlnode-controlnode·¶ transresistance·Example10.4 :H 6 4 VB 20 (i.e. a CCVSbetweennode6 and4, dependenton currentthroughthevoltage sourceVB,andthegain-transresistanceis 20.)

For thecircuit in Fig. 10.4,CCVSwouldbedescribedby the following line in the inputfile:

V0 5 2 0VH 3 0 V0-400


Thepolarity of thedummyvoltage sourcedependsonthedirectionof thecurrentcontrol-ling thedependentsource.

15 V

R1

50 ¼

Ω

R2

R3

R5500 ¼

Ω 150 Ω

0½

1 2¾

3¿

5¼

3 I¿

x

Ix

500 À

Ω

0 v½

50 À

ΩR4

4

+Á- 400 Ix

H

Figure10.4:Current-controlledvoltagesource

Independentcurr ent source: ThesyntaxisI[name] Â +nodeÃ!Â -nodeÃ [dc] Â valueÃ

Resistance:ThesyntaxisR[name]Â +nodeÃÂ -nodeÃÂ valueÃ

Independentvoltagesource: ThesyntaxisV[name] Â +nodeÃÂ -nodeÃ [dc] Â valueÃ

DC sweepcommand: Thesyntaxis.DC ¡sweepvariable¿¡startvale¿¡stopvale¿¡increment/step¿

Operating point command: Thesyntaxis.OP

Options command: Thesyntaxis.optionsnopage

Print command: Thesyntaxis.PRINTDC Â outputvariablesÃExample10.5 : .print DC V(5) I(R1) I(RL)

Transfer Function command: Thesyntaxis.TF Â outputvariableÃÂ inputvariableÃTheTF commandwill give input resistanceandoutputresistance( Ä5ÅÆ ) in theoutput file. For example,the following TF commandsusedin the circuits ofFigs.10.1through10.4are:

10.5. PROCEDURE 55

.TF V(4) V

.TF V(3) V

.TF V(3) V

.TF V(4) V

End command: Thesyntaxis.ENDIt flagstheendof the input file. It tells PSPICE that thereareno morestatementsin thefile.

10.5 Procedure

1. Analyzethecircuitsshown in Figs.10.1through10.4by hand.

2. Simulatethecircuitsshown in Figs.10.1through10.4withPSPICE.

3. Highlight thecurrentandvoltageson theoutputfilesobtainedin step2.

4. Comparevaluesobtainedin step1 andstep3 by presentingtheresultsin tabularform.

5. Submitthehandcalculations,andtheoutputfiles, alongwith comparisontableasa reportfor this lab.

6. For the circuit taken from Laboratory7 shown in Fig. 10.5,find the TheveninandNorton’s equivalentcircuits by handcalculations.Using handcalculationsfind the loadresistancethatwill deliver maximumpower to the loadresistance.Use ÇÈtÉcÊVË&Ç and Ä`ÌÉcÊVË5Í@Î .

Vs

R1

RL

1 kΩaÏ

bÐ

Figure10.5:Equivalentcircuit

7. Verify the resultsobtainedin step6 with PSPICE simulation,andcompareyourhandcalculationandsimulatedvalues.


8. Submit the handcalculationsfor circuit shown in Fig. 10.5,andoutputfile ofPSPICE simulationfor circuit in Fig. 10.5 verifying the Thevenin’s, Norton’s,andmaximumpower theorem.Highlight theresultsin theoutputfiles.

9. Presentthecomparisonof calculated,experimental(i.e. from Lab.-7), andsim-ulatedvaluesin a table.

Laboratory 11

Measurementof Capacitanceand Resistance

Analysisandmeasurementsof resistance-capacitance(RC)circuit. Investigatethestepresponseof RC-circuit.

11.1 ObjectivesÑ AnalyzeRCcircuit.

Ñ Verify currentandvoltagesof RCcircuit usingOscilloscope.

Ñ Familiarizewith exponentialwaveform.

Ñ Find time constantof RCcircuit.

Ñ Learnparallelandseriescombinationof capacitors.

Ñ Identify thecharginganddischarging timeof thecapacitor.

Ñ Find risetimeandfall time of theoutputwaveform.

11.2 EquipmentÑ Digital Multimeter(DMM).

Ñ Oscilloscope.

Ñ FunctionGenerator.

Ñ DC PowerSupply.

Ñ Protoboard.

57

58LABORATORY 11. MEASUREMENTOF CAPACITANCE AND RESISTANCE

Ñ Connectingcablesandconnectingwires.

Ñ Capacitorsandresistors.


Chapter6 of thetextbook,ElectricCircuitsby Nilsson.



11.5 Procedure

1. Build thecircuit shown in Fig. 13.2on theprotoboard.For theinput voltage ÇÈusethe functiongeneratorandselectthe5 V PP (peakto peak)squarewave offrequency six timesgreaterthanthe time constantÒ , i.e., frequency ÓÔÕÊÖ×XÒ .Adjustthetime-baseof theoscilloscopeto displaytwo cyclesof thesquarewave.

R=1 kΩ

C=1 Ø

µf

+Ù

-

v(t) to oscilloscopeÚsignal generatorÛsquare waveÛ

Figure11.1:RC circuit

2. Displaytheinputsquarewave Ç È ononechannelof theoscilloscopeandthevolt-ageacrossthecapacitorV(t) on theotherchannelof theoscilloscope.Measurethe peak-to-peakvalueof outputvoltage,periodof the input andoutputwave-form, andidentify thecharginganddischargingof thecapacitorfrom theoutputwaveform.Sketchthewaveformin your labnotebookandalsoobtainaprintoutof thewaveform,which will beusedin thelab. Report.

3. Measurethetime constantfrom theoutputwaveform. Thetime constantÒ willbedeterminedby theintersectionof thetangentline to thecurve at ÜÉcËXÝ andthetimeaxis.Theslopeof thetangentis ÇÈ6ÖÞÒ .

11.5. PROCEDURE 59

4. Find the risetime (charging time of capacitor),andfall time (dischargetime ofcapacitor)from the outputwaveform. Rise time is the time it takesthe ouputvoltageto go from ËZßàÊYÇÈ to ËZß áWÇÈ , andthe fall time is the time it takesfor theoutputto fall from ËZß áWÇÈ to Ë@ßâÊÞÇÈ . From the measurementsprove that the fol-lowing relationshipbetweenriseor fall timeandtimeconstanthold

ÜäãdÉÒtåàædáçÉQèZß èÒ and ÜêébÉÒåàædábÉëèßèÒ (11.1)

Recordvaluesin thenotebook.

5. Build circuits shown in Fig. 11.2andFig. 11.3. Display the input andoutputwaveforms,andrepeatthemeasurementsmentionedin step2 throughstep4.

R=1 kΩ

C1=1 µf

+

-

v(t) to oscilloscope

signal generator

square wave

C2=1 µf V1(t)

Figure11.2:Capacitorsin series

R=1 kΩ

C1=1 µf

+

-

v(t) to oscilloscopesignal generator

square waveC2=1 µf

Figure11.3:Capacitorsin parallel

6. Comparemeasurementsfor thethreecircuits,i.e.,Figs.13.2,11.2,and 11.3withtheir calculatedvalues.Presentcomparisonin tabular form in thelab report.

7. Discussin your report the following questions:What is the randomerror thatyou mayuseto explain the differencebetweencalculatedandmeasuredvaluesof time constant,rise-time,and fall-time? How accurateis the time constantmeasurementfrom theprintoutof theoutputwaveform?Is it truethatacapacitorrequiresa finite periodof time to chargeto the final value?Find the ìÒ valuesfor thethreecircuits,andcommentson the ìÒ value.

60LABORATORY 11. MEASUREMENTOF CAPACITANCE AND RESISTANCE

Laboratory 12

Measurementof InductanceandResistance

Analysisandmeasurementsof resistance-inductance(RL) circuit. Investigatethestepresponseof RL-circuit.

12.1 ObjectivesÑ AnalyzeRL circuit.

Ñ Verify currentandvoltagesof RL circuit usingOscilloscope.

Ñ Familiarizewith exponentialwaveform.

Ñ Find time constantof RL circuit.

Ñ Learnparallelandseriescombinationof inductances.

12.2 EquipmentÑ Digital Multimeter(DMM).

Ñ Oscilloscope.

Ñ FunctionGenerator.

Ñ DC PowerSupply.

Ñ Protoboard.

Ñ Connectingcablesandconnectingwires.

Ñ Inductancesandresistors.

61

62 LABORATORY 12. MEASUREMENTOF INDUCTANCE AND RESISTANCE


Chapter6 and7 of thetextbook,ElectricCircuitsby Nilsson.



12.5 Procedure

1. Build thecircuit shown in Fig. 13.3on theprotoboard.For theinput voltage ÇÈusethefunctiongeneratorandselectthe5-V PP squarewaveof half-timeperiodequalto ×Ò or a period12 timesgreaterthanthetime constantÒ , or ÓÉ ÊÖ/ÊYèÒ .Adjustthetime-baseof theoscilloscopeto displaytwo cyclesof thesquarewave.

2. Choosethe valuesof resistanceÄ andinductanceí for a time constantÒ be-tween100 î secto 300 î sec.Useonly resistancesavailablein a shelved-boxinthelab,andtheinductanceí from thedecadebox.

R

+ï

-

v(t) to oscilloscopeðsignal generatorñsquare waveñ L

Figure12.1:RL circuit

3. Display the input squarewave ÇÈ on onechannelof oscilloscopeandthe volt-ageacrossthe inductor òó¹Üêô on theotherchannelof the oscilloscope.Measurethe peak-to-peakvalueof outputvoltage,periodof the input andoutputwave-form, and identify the exponentialdecayof voltageacrossinductor. Measurethe voltageacrossthe resistance,òõ andfind the currentthroughthe inductor,ö Ì÷ÉëòõøÖÄ . Sketchthewaveformin your lab notebookandalsoobtaina print-out of thewaveform,whichwill beusedin thelab report.

4. Measurethetime constantfrom theoutputwaveform. Thetime constantÒ willbedeterminedby theintersectionof thetangentline to thecurve at ÜÉcËXÝ andthetimeaxis.Theslopeof thetangentis ÇÈ6ÖÞÒ .

12.5. PROCEDURE 63

5. Build circuit shown in Figs.12.2,12.3,and12.4. Display the input andoutputwaveforms,andrepeatthemeasurementsmentionedin step2 throughstep4.

R

+ï

-

v(t) to oscilloscopeðsignal generatorñsquare waveñ

L1

L2

Figure12.2:Seriesinductors

R

+

-


signal generator

square wave L1 L2

Figure12.3:Parallel inductors

6. Comparemeasurementsfor the four circuitsof Figs.13.3,12.2,12.3,and12.4with their calculatedvalues.Presentcomparisonsin tabular form in the lab re-port.

7. Discussin your report the following questions:What is the randomerror thatyou mayuseto explain the differencebetweencalculatedandmeasuredvaluesof the time constant?How accurateis thetime constantmeasurementfrom theprintoutof theoutputwaveform?Is it truethat inductorsrequirea finite periodof time to establishthe cureent’s final value? Find the ìÒ valuesfor the fourcircuits,andcommentson the ìÒ values.

64 LABORATORY 12. MEASUREMENTOF INDUCTANCE AND RESISTANCE

R1

+

-


signal generator

square wave L1R2


Laboratory 13

Evaluation of RC and RLCir cuits via SPI CE

Analysisof RCandRL circuits,andtheir verificationby simulationwith PSPICE.

13.1 ObjectivesÑ UnderstandthePSPICEcommandsfor capacitor, inductance,andvoltagepulse.

Ñ Verificationof RC,andRL circuitsanalysisusingPSPICE.

Ñ CompareRC andRL circuit analysisby hand,PSPICE simulationandmeasuredvalues.

Ñ Comparetheprobeoutputof PSPICE simulationof RC andRL circuitswith thewaveformsobtainedfor RC andRL circuitsin Labs11 and12

13.2 EquipmentÑ PCwith studentversionof PSPICE (TraftonE 110)

13.3 Pre-Lab Assignment

Readchapter2 (2.7 and2.8), andChapter11 of the recommendedbook, SPICE3rdEdition,By PaulW. Tuinenga

13.4 Intr oduction

Following is thesummaryof commandsthatyou mayneedfor theanalysisof circuitsin this lab.

65

66 LABORATORY 13. EVALUATION OF RCAND RL CIRCUITSVIA SPICE

Capacitor: ThesyntaxisC[name]n+ n- [valueof capacitor][initial condition(IC) value=initial voltage]

Example13.1 :

C1 1 0 20uFIC=10.5vC1 1 0 20uF

Inductance: ThesyntaxisL[name]n+ n- [valueof inductance][initial conditions(IC) = initial current]

Example13.2 :

L1 1 0 1mHIC=10E-6AL1 1 0 1mH

Toggleswitch: ThesyntaxisS[name]n+ n- [+controlnode][-control node][modelname]

Example13.3 :

S11 2 4 0 Toggle1.ModelToggle1Vswitch

Thecontrol pulseis appliedbetweennode4 andnode0. Whenever thecontrol pulseis1V, theswitch will beclosed,and for 0V volt, theswitch will beopen.Thepulsewill bedefinedsothatToggle1closesat 1 secondandstayclosedfor 6 seconds.

Voltagepulse: ThesyntaxisV[pulsename]n+ n- Pulse[V1V2 TD TR TF PW PER]

Example13.4 Vpulse14 0 Pulse[01 1 1M 1M 6]

SeeFig. 13.1for a descriptionof theparameters.

Parameter DescriptionV1 Initial pulsevoltageV2 Final pulsevoltageTD Timeafterzeroat whichpulsebeginsTR Time it takesfor thepulseto go from voltageV1 to V2PW Timeat which thepulseremainsatV2PER Time it takesfor thepulseto repeat.For a singlepulse,thetime is infinite.

If no parameteris givenfor PER,PSPICE assumesasinglepulse.

Table13.1:Parametersof avoltagepulse

13.4. INTRODUCTION 67

timeù

voltage

Tr TfPW

V2

V1

TD

PER

Figure13.1:Pulseparameters

Transient Statement: Thesyntaxis.Tran[time interval] [final timevalue]UICWhereUIC standsfor ”use initial conditions”. If UIC is specifiedin .TRAN statement,PSPICE will skipDC biascalculationandinsteaduseonly theIC informationsuppliedoneachcapacitoror inductorstatement.

Example13.5 :

.Tran0.36 UIC

In this statementthe timeinterval betweendatapoint is 0.3secondsfor a total of 6 sec-onds.

Example13.6 Input file for RCcircuit of Fig. ??:Analysisof RCcircuitV11 0 12V*DefiningToggle1switchVpulse14 0 Pulse(01 1 1M 1M 6)Stoggle11 2 4 0 Toggle.ModelToggleVswitchRpulse14 0 1OhmR12 3 1KohmC13 0 1E-3IC=0volt*Control statement.Tran 0.36 UIC.Print Tran v(3) v(2,3).Probe.Optionsnopage.End


12 V

+

-

1 mf

1 kΩ

0

1 23

Vpulse Rpulse

0ú

4

+

-

Figure13.2:RC circuit

Example13.7 Input file RL circuit of Fig. 12.4:Analysisof RL circuitV11 0 100V*DefiningToggle1switchVpulse14 0 Pulse(01 1M 1E-121E-1210)Stoggle11 2 4 0 Toggle1.ModelToggle1VswitchRpulse14 0 1OhmR12 3 1KohmL1 3 0 1H IC=0A.Tran 0.3M7M UIC.Print Tran V(2,3)V(3) I(R1).Probe.Optionsnopage.End

100 V

+

-

1 H

1 kΩ

0

1 23

Vpulse Rpulse

0ú

4

+

-


13.5. PROCEDURE 69

13.5 Procedure

1. AnalyzetheRCcircuitsfrom Lab11,andRL circuitsfrom Lab12by hand.

2. Simulatethe RC circuits from Lab 11, and RL circuits from Lab 12 usingPSPICE.

3. Highlight thecurrentandvoltagesin theoutputfile, andcomparetheprobeout-putwith thewaveformobtainedfromtheoscilloscopefor theRCandRL circuits.

4. Submityourhandcalculations,PSPICE outputfile, andprobeoutput,alongwitha tablecomparingthehandcalculated,simulated,andmeasuredvalues.

5. Solve problem7.6 from the textbook, andverify the resultsby simulatingthecircuit with PSPICE. Submit handcalculations,output file (highlight voltagesandcurrents),andtheprobeoutput.


Appendix A

Laboratory Notebook

Oneof the objectivesof this laboratorycourseis learningto keepa goodnotebook,whichkeepsanaccurateandcomprehensiverecordof your laboratorywork. Thenote-bookis extremelyimportantin researchanddevelopmentorganizations.Many patentshave beendecidedby thecompleteaccountof work in thenotebookor lack of entriesin thenotebook.

Theintentionof maintainingagoodnotebookis to cultivatehabitof keepingcom-pleterecordof experimentalwork. Your notebookshouldbe like a diary, recordingdaily work in the lab in the form of datatables,sketchesof diagrams,interpretationof data,speculationaboutresults,calculations,causesof failureof experiment,possi-ble sourcesof error, deviation from expectedresult,plan to repeatandfix the errorspreviouslymade.Thefollowing suggestionswill helpyou to keepagoodnotebook:

1. Thenotebookmaybeany notebookwith fastened-inpages.

2. Write all entriesin ink. Write nameandcoursetitle numberon the front page.Includeyourphonenumberandemail in caseyournotebookis misplaced.

3. Date every pagewhen you recordyour work. Placetable of contentsin thebeginningof thenotebookshowing date,experimenttitle, andpagenumber.

4. Numberall pagesof thenotebook.Do not tearoff any page.If youwantto omita page,crossout thatpage.

5. Labelall graphs,tablesanddiagrams.

6. Write on onesideof thepageandtheentriesshouldbelegible.

7. Do not write thingson piecesof paper, thengo home,andcopy themin yournotebook.Make entriesdirectly into your notebook.You will not have time towrite thingstwice.

8. If youmakea mistake,crossout.

71

72 APPENDIXA. LABORATORY NOTEBOOK

9. Do notspendlot of timein makingtablesandfancy figures.Themainpurposeofthenotebookis to keepagoodrecordof work, whichshouldbeableto reproducework recordedin it two yearslater.

10. Recordtheinstrumentused,its modelnumber, manufacturer, andspecifiediden-tifier, for EE240labbenchstationnumberis sufficient.

11. Eachstudentshouldhave his/hernotebook.You andthe lab partnermustsignanddatethenotebookat theendof thelabsession.

12. Don’t copy materialfrom otherstudent’snotebook

13. You mustshow your laboratorywork enteredin thenotebookto the laboratoryinstructor. Theentry in thenotebookshouldbesignedanddatedby lab instruc-tor. If the notebookis not checked by the laboratoryinstructor, you will notreceiveagradefor your laboratorywork.

A goodnotebookcanbejudgedby answeringthefollowing questions:

(i) Cansomeonewell versedwith your work canrepeatyour resultsby following thenotesfrom yournotebook?

(ii) After a periodof six monthsor more,canyou make senseof your work in yournotebook?

If theansweris yesto thequestionsabove,thenyouarekeepingagoodnotebook.

Appendix B

Laboratory Reports

In additionto keepingrecordof your laboratorywork in anotebook,eachgrouphastosubmitonereportfor eachlaboratorysessionfor grading.Thelaboratoryreportwritingshouldbeajoint effort betweenthetwo students.In thereport,indicatewhohaswrittenwhichsection.Themainpurposefor thereportis to communicatetheresultsto othersandto enableothersto duplicatethework in a straightforwardmanner. On the otherhand,thelabnotebookis for yourown benefitandrecordkeeping.

Thefollowing descriptionwill provideguidelinesfor thepreparationof labreportsandsubmission

When to Submit: The laboratoryreportsareduebeforenext laboratoryexperiment,unlessannouncedotherwisein the lab. Late lab reportswill be returnedwith-out gradingunlessthelaboratoryinstructorhasgivenexplicit permissionof latesubmission.

Format of Report: The lab reportshouldbe typedin a type sizeof 10 to 12 points.(No lab reportwill beacceptedwith font sizesmallerthan10 points). You canuseword processor. Reportsmustbe stapledin the upperleft-handcornerandhave2.5cmmarginsat thetop,bottomandoneachside.Pagessubmittedshouldbeof standardsize8.5”x11.5”. Line spacingis at thediscretionof thereporter.The lengthof a typical reportshouldnot exceedfive pages.The reportshouldcontainthefollowing.

Cover sheet: Statingexperimenttitle, dateperformed,nameof two studentsinthegroup,coursenumberanddepartment,university.

Report Summary: Objectives - The summaryshouldbe no longer than 100words.Thesummaryshouldbewritten in third personandshouldincludea statementof objectives,methods,observations,andbrief discussionofresults.

Body of Report: Experimentalresults- The main body of reportshouldbe aclearstatementof measurementsetup,schematicdiagramincludinginstru-mentsusedwith modelnumber, benchnumber, thesummaryof measure-mentsin the form of tables,graphs,andsimulations.This sectionshould

73

74 APPENDIXB. LABORATORY REPORTS

not be more than four pagesincluding tables,graphs,etc. You canalsoincluderesultof PSPICEsimulationin thereportif appropriate.

Conclusions: This is an importantpartof the report. It shouldcontainthefol-lowing items: summaryof results,mentionwhatyou have learnedspecif-ically mentioningmainpurposeof lab in relationto lectures,comparethemeasuredvalueswith expectedvaluesandexplain any error or deviation.A critiqueof themeasurementtechniquesandrecommendationto improvethe experimentis stronglyencouraged.This sectionshouldnot be moreonepage.

Youmustsignanddatethereport.It is expectedthat you will discussyour experimental procedure, data, and

resultswith eachother, but you are responsibleto presentyour work in writtenform, i.e. lab report should be your original work. If you areusing data collectedby other group, you shouldacknowledgethe fact in writing separatelyin your labreport. Copying of other lab reportswill be tr eatedascheatingand may resultasgroundsfor failur eof the course.

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