AStudentGuidetoIntroduceMultisim,LTSpice,andMathcadforECE3043attheGeorgiaInstituteofTechnology

ArchitRJainSchoolofElectricalandComputerEngineeringStudent

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Table of Contents 1 Introduction…………………………………………………………………………………………….3 2Backgrounds…………………………………………………………………………………...4 2.1Multisim……………………………………………………………………………..4 2.2LTSpice……………………………………………………………………………….4 2.3Mathcad……………………………………………………………………………...53Multisim…………………………………………………………………………………………6 3.1Hints…………………………………………………………………………………124LTSpice…………………………………………………………………………………………135Mathcad………………………………………………………………………………………..176References…………………………………………………………………………………...19

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1 Introduction                   AsaECEstudenttherearemanychallengingclassesfilledwithnewmaterialthatwehavetotake.Theseclassesintroduceanythingfromnewtypeofcircuitstonewsoftwareandnewprograminglanguages.Thisguideistohelpstudentslearnnewlabsoftwares.SoinECE3043studentshavetolearnhowtouseMultisim,LTSpice,andMathcad,inordertocompleteallofthefuturehomeworksassignments.AsacurrentstudentinECE3043IknowhowmuchofahardtimeIhaddoingthefirsthomework,becauseIdidnotknowhowtousethesesoftwares.ThepurposeofthisusermanualistoteachcurrentECE3043studentshowtouseMultisim,LTSpice,andMathcad.Additionallytherewillbehintsgivenastotheirfuturehomeworks.Thefirstthingdiscussedinthismanualwillbebackgroundforthreesoftware,thangothroughstep‐by‐stepinstructiononhowtousethisthreesoftwares.

  

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  2 Backgrounds                    2.1 What is Multisim NIMultisimisanelectronicschematicandsimulationprogramthatispartofcircuitdesignclass,alongwithNIUltiboard.MultisimisoneofthefewcircuitdesignprogramstoemploytheoriginalBerkeleySPICEbasedsoftwaresimulation[1].Multisimiswidelyusedinacademiaandindustryforcircuit’seducation,electronicschematicdesignandSPICEsimulation[1].ThelatestversionofMultisimenrichespowerfulsimulationtechnologywiththeabilitytoanalyzeanalog,digital,andpowerelectronicacrosseducation. 

 Figure1.Multisimlogo[1]

 

2.2 What is LTSpice  LTSpiceishighperformanceSPICEsimulator,schematiccaptureandwaveformviewerwithenhancementsandmodelsforeasingthesimulationofswitchingregulators[2].LTSpiceisnode‐unlimitedand3rdpartymodelscanbeimported.Circuitsimulationsbasedontransient,AC,noiseandDCanalysiscanbeplottedaswellasFourieranalysis[2].LTSpiceIVisusedinmanyfieldsincludingradiofrequencyelectronics,powerelectronics,digitalelectronics,andotherdisciplines.

Figure2.LTSpicelogo[2]

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2.3 What is Mathcad  PTCMathcadistheindustrystandardsoftwareforsolving,analyzing,andsharingyourmostvitalengineeringcalculations[3].Ithasmathematicalnotation,unit’sintelligence,andpowerfulcalculationcapabilities,presentedwithinandeasy‐to‐useinterface,allowsengineersanddesignteamstocapture[3].Mathcadalsointegratesthesehuman‐readable,livecalculationswithplots,graphs,text,andimagesintoasinglepresenteddocument.

Figure3.Mathcadlogo[3]

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 3 Multisim                     AsstatedearlierMultisimisanelectronicschematicandsimulationprogram.Thebestwaytolearnthisprogramistogothroughastep‐by‐stepinstructiononhowtodrawthefollowingcircuit(Figure4)onMultisim.

Figure4

InMultisim,allthecomponentsarerequiredtohavevalueforthecircuitbeforetheschematic.Ifthevaluesarenotgivenonthehomeworksheetthentheprofessorwillprovideequationsinclassforittobesolvedforthespecificvalues.ButforthisspecificcircuitthevaluesthatwillbeusingareR=4.3kOhms,L1=7.3H,andL2=3mH.

1. BeginbyopeningMultisimsoftwarefromstartmenu.Forthelogo

referbacktoFigure1.OncethesoftwareisopenedisshouldlooklikeFigure5.

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Figure5:StartingscreenofMultisim

2. Aftertheprogramisopenedgatherallcomponentsfromthefolder.

TodosoclickonPLACEonthemenubarthenclickonCOMPONENTandthescreenshouldlooklikeFigure6.

Figure6:ComponentFolder

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Nowthatthescreenisup,clickonthedropdownmenuunderGROUP,clickonSOURCES,clickonPOWERSOURCESthenGROUNDandclickOK.

3. Onceallthegroundssymbolsareplacedontheschematic,navigatetothesamescreen(Figure6)butthistimeunderGROUPandSOURCES,clickonSIGNALVOLTAGESOUCE.InthisclasstheonlysourcethatwillbeusedisACsource,sothereforethisclassusesACVOLTAGEunderCOMPONENT.{LaterinthesemesterPiecewiseLinearsourceisgoingtoberequiredinordertosolvethehomeworkproblemandalsoaddininitialvoltage.}

4. Navigatetothesamescreen(Figure6)thistimeunderGROUPclickonBASICandundertheGROUPtheresomethingcalledFAMILY.UnderFAMILYthereisadifferenttypeofcomponentssuchasresistors,capacitors,andinductors,etc.Butforthisspecificcircuititsrequiredtouseinductorsandresistor,andshouldlooklikeinFigure4.SoinFAMILYclickonRESISTOR(R)andunderCOMPONENTwritethevalueof4.3kandclickOK.Dothesamethingforthetwootherinductors(Butinthehomeworktherewillhavedifferentvalues).

5. Afterthecompletionofstep5,yourwindowinMultisimshouldlook

likethefollowinginFigure7.

Figure7:Withallthecomponents

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6. NowletsrearrangethecomponentstomatchFigure4.Alsoinductor(L2)needstoberotated.TorotatethecomponentHIGHLIGHTtheelementandRIGHTCLICKandselectROTATE90OCLOCKWISE.CLICKonit.Thisshouldrotatethecomponent.Afterthat,justconnectcomponentslikeitwasrequiredinQUARTUSusinglines.

7. OnceallthecomponentshavebeenrearrangedtomatchFigure4,theschematicneedslabelingofVinandVout.Todoso,RIGHTCLICKonthelinebetweentheSOURCEandtheNODEandclickonPROPERTIES,thenunderthetabNETNAME,PREFFEREDNETNAME.SelectwriteVin,andCHECKtheboxforSHOWNETNAMEsoitcanappearonyourschematic.

8. RepeatthestepforVoutbetweentheinductorandresistorline,and

yourpropertiesboxshouldlooklikeFigure8andyourdrawingshouldlooklikeFigure9.

Figure8:Propertiesbox

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Figure9:Componentrearrangedandconnectedwithline

9. Aftertheschematichasbeencreateditneedstobesavedtothe

folder.Onceit’ssaved,graphthebodeplotforthiscircuit(Figure5).Todoso,onthemenubarCLICKonSMIULATEandthanCLICKonANALYSIS.ThiswilldisplayanotherdropmenuandclickonACANALYSIS.Oncethatisclicked,getaboxwherethefirsttab‐FREQUENCYPARAMETERS.Changetheparametersbasedontheprofessor’spreference,butforthiscircuitkeeptheparametersunchanged(asgiveninthebox).RightnexttotheFREQUENCYPARAMETERSlocatesomethingcalledOUTPUTandCLICKonit.Oncethetabisopened,locateALLVARIABLEandselectVoutandCLICKonADDforanalysis.ThescreenshouldlookasfollowinginFigure10.

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Figure10:ACanalysisoutput

10. AfterVoutisontheanalysisside,CLICKonSIMULATEandgetthe

screenthatlookslikeinFigure11.

Figure11.Graphaftersimulating

 

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3.1 Hints: 1. WhendoingthefirstordercircuithomeworkinMultisim,for

thevoltagecomponentusepiecewiselinearvoltagesource.2. Also,inthefirstordercircuithomework,makesureprimary

andsecondaryy‐axesareenabled.3. Aftertheschematicisfinalized,clickonFILE,thenSNIPPET,

andSAVESNIPPETASSELECTION.4. Afterthesimulationisdone,youcansaveitasaPDFwhenyou

clickonprint.5. Inthehomeworkwhenitsaysplotbodeplot,itisthesameas

plottingACVOLTAGEANALYSISundertheSMILULATIONtab.

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4 LTSpice                      Asmentionedearlier,LTSpiceisaschematiccaptureandwaveformviewerwithenhancementsandmodesforeasingthesimulation.LTSpicecanbeusedintwospecificways‐firstisbydrawingschematic,andthesecondoneisbywritingcodeusingnotepadthanopenitinLTSpice.InthissectionoftheintroductorymanualthecodingpartofLTSpicewillbemoreappropriatetostudy.ThesameschematicfromFigure4canbeappliedtolookatthecodinginLTSpice.

1. TheexamplecircuitFigure4usedinMultisimwillalsobeusedinLTSpice.ThecodewillbewritteninnotepadandthenSAVEDasa.CIRfile.

2. ThefirststepincodinginLTSpiceistolookatthenodeinMultisim.OncethenodehasbeengatheredfromMultisimforthisspecificcircuit,writingthecodeiseasyinLTSpice.{Thenodeinthehomeworkwillbedifferentaccordingtothecircuit.}

3. Firstlineofthecodeisalwaysacommentlinewiththestudentsname

and/orthenameofthegraphorthehomework.

4. Thesecondlineisstatingtheinputvoltageatnode1and0andtheACstandsforACVOLTAGESOURCEusedinMultisimand1kstandsforinputFREQUENCY.

5. Inthenextthreelineofcodes,thelefthandsideofthecodeisLETTERofthecomponents,thecenterpartisthenodeofthecomponentsrepresentedinthecircuit,andtherighthandsideofthecodeisthevalueofthecomponentgiveninhomeworkorthecalculatedvalue.

6. Thelinethatcomesafterallthecomponentvaluesis.acdec301010k,inLTSpice.acmeansthatthegraphisgoingtobeACVOLTAGEANALYSIS,dec301010kjustmeansthatLTSpiceisusingdecimalvaluesandwith30numberofpintsandstartingvalueis10Hzfrequencyandendvalueis10kHzfrequency.

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7. Finallythelasttwolinesofcodeis.probeand.end;firstthe.probe

tellsLTSpicetowritetheresultofDC,AC,orTRANSIENTSIMULATIONinprobegraphicform,secondthe.endistellingLTSpicetoendthecodehere.{FormajorityofthehomeworkprofessorBrewerwillprovidetheoutlineofthecode.}

8. Nowsavethecodeinnotepadanditshouldlookasthefollowing

Figure12.

Figure12.CodeWritteninNotepad

9. Afteralltheofcodeiswrittenonceagainsaveitasa.CIRfile,then

openitinLTSpiceandshouldlookasfollowingFigure13.

Figure13.HowLTSpiceshouldlook

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10. NowCLICKontherunbuttonthatlookslikeaguyrunningonthemenubarindicatedwiththeredcircle,intheFigure14,andthescreenonLTSpiceshouldlookasfollowingFigure14.

Figure14.AfteryouCLICKrunwithoutgraph

11. NowRIGHTCLICKonthegraphandCLICKonVISIBLETRACEand

pickouttheoutputVOLTAGE.ButforthisspecificcircuittheoutputvoltageisgoingtobeV[2].AfterselectingtheoutputthescreenshouldlookasfollowingFigure15.

Figure15.Screencapturewithgraph

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12. Afterthesimulationisdonesavethecodingandgraphasa.PDFfilesolateritwillbeeasiertoprintlateron.

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5 Mathcad                     Asmentionedearlier,Mathcadisastandardsoftwareforsolvingandanalyzingthemostvitalengineeringcalculations.Mathcadhasmathematicalnotation,unit’sintelligence,andhasaneasy‐to‐useinterface.Thesamecircuit(Figure4)thatwasappliedinMultisimandLTSpicewillbeusedhere,toseehowthesoftwareworks.1. InMathcad,whentheREDPLUSsingappearsonthescreenyoustart

typingintheequationsgivenintheclassorthecalculatedequationinthehomework.

2. ForthecircuitrepresentedinFigure4,letswritedownallthecomponentvaluesandtheequationsthatweregiventous.

3. Forexample,thewaytowriteinacomponentinMathcadistosayR:=4.3kΩ,bywriting:=itsstatingthatRisequaltothatvalueandtogetohmsymboloranyothersymbolinMathcadsimplyjustCLICKonMEASURINGCUPontheCOMMANDBAR.

4. OncealltheequationsandthecomponentvaluesarewritteninMathcad,thescreenshouldlookasfollowingFigure16.

Figure16.Afteralltheequations

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5. NowCLICKontheGRAPHSYMBOLontheCOMMANDBAR,andablankgraphscreenshouldappear.Inorderforthelinetoappear,FREQUENCYhastobementionedinthex‐axises,whichisrepresentedbyfi,andonthey‐axiseswehavethemagnitudeandphaseequationthatarerepresentedbyMandPHI.Aftertheyareinputted,thescreenshouldlookasfollowingFigure17.

Figure17.Mathcadwithgraphs

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6 References:                    [1](2014,March2).WhatisMultisim?[NationalInstrument].Available:http://www.ni.com/multisim/what‐is/[2](2014,March3).WhatisLTSpice?[LinearTechnology].Available:http://www.linear.com/designtools/software/[3](2014,March3).WhatisMathcad?[Product&ServiceAdvantages].Available:http://www.ptc.com/product/mathcad/about/