DigitalSystemswithLabENGIN241

Lab1- Presentation

Dr.Honggang ZhangEngineeringDepartment

UniversityofMassachusettsBoston

Today’sLab• UseLogisim tobuildandsimulateasimplelogiccircuit.

– TheschematicisonPage20ofslideL02.pptx.pdf.– PutyourLogisim simulationscreencapturesintoyourLab1report.– Youneedtoshowinyourreporttheoutputresultsofatleast4input

combinationsfromyoursimulation.Youcandoascreencapturetogetanimageofeachsimulationandputitintoyourlabreport.

– WritedowntheTruthtableofthecircuitandcompareitwithyoursimulationresults.

• Buildasimplecircuitonbreadboard,usingsomelogicgatesinourlabkit.– Testa7400NANDgatetoobservetheoutputvalueforall4inputlogiclevels.

UseLEDtoshowalogicoutput.– Beforeyouleave,showyourcircuitworktotheinstructorandLabAssistants.– Takeapictureofyourcircuitonbreadboardandrecordyourobservation,and

putthemintoyourlabreport.

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Today’sLab(cont’d)

• WriteLab1report.– Asktheinstructorforanyformatquestions.– Doasmuchworkaspossible,asyouwillneedtosubmitPre-Lab

reportnextThursday.

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Breadboard

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PowerandBreadboardWiring• Thechipsareplacedabovethechanneloneithersideofthebreadboard,suchthateachpinofyourchipwillhaveseveralavailablewirereceptorsforeasysolder-freewiringofyourcircuits;

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7400Chip

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ICPackagingIC’sandotherelectronicdevicesareavailableinavarietyofpackages.ThetablebelowwastakenfromaJameco Electronicscatalog.MostoftheIC’sthatwillbeusedinlabwillbeDIP(DualIn-linePackages).

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DIPSwitches• DIPswitchesaregroupsofsimpleslideswitchesinDIPpackages.• DIPswitchesarecommonlyusedoncircuitboardstoselectoptions.Youmayhaveseenthemusedinprinters,modems,remoteforgaragedooropeners,etc.

• DIPswitchesarecommonlyavailablewith2-12switches(poles).• DIPswitchesusuallyhaveOFForONmarkednexttooneswitchposition,where

• ON=closedswitch• OFF=openswitch

12-poleDIPSwitch(Reference:www.allelectronics.com)

4-poleDIPSwitch(Reference:www.jameco.com)

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DIPSwitches

4-poleDIPSwitch:Appearance(Reference:www.jameco.com)

SlideswitchtoONpositiontoclose.

1 2 3 4

4-poleDIPSwitch:Schematic

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UsingDIPSwitchestoprovideHIGHandLOWinputsSinceaDIPswitchsimplymakesorbreaksaconnection,aresistorneedstobeusedtoinordertouseittoprovideeitheraHIGHorLOWinputtoalogicgate.

OFForopen(HIGH)

ONorclosed(LOW)

2.2k

+5V

switchoutput

DIPswitch

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Usinga4-poleDIPswitchtoprovide4circuitinputs

F=AB+CD

2.2k

+5V

2.2k

+5V

2.2k

+5V

2.2k

+5V

F

AB

CD

DIPSwitch

OFF=OpenSwitch=HIGHinputON=ClosedSwitch=LOWinput

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DiodeAdiodeisasemiconductordevicethatactssomewhatlikeavoltagecontrolledswitch.Thesymbolforadiodeisshownbelow.Thepositiveterminalofthediodeiscalledtheanodeandthenegativeterminalisthecathode.

anode cathode

V+ _

DiodeSymbol

anode cathode

V+ _

DiodeAppearancePicturesofdiodes(Reference:www.allelectronics.com)

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LED(Lightemittingdiode)LED’sarediodesthatemitlightwhentheyareforwardbiased (apositivevoltageplacedacrosstheLEDfromanodetocathodeasshownbelow).TheamountoflightproducedisproportionaltothecurrentthroughtheLED

anode cathode

V+ _

Forward-biasedLED

anode(long)

cathode(short)

LED:Physicalappearance

Luminous

I(mA)12 20

destructionintensity

TypicalLEDcharacteristics

PicturesofLEDs(Reference:www.allelectronics.com)

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LED(Lightemittingdiode)Theresistance ofanLEDissufficientlylowsuchthatifafewvoltsisplaceddirectlyacrossanLED,itwillbedestroyed.Therefore,acurrent-limitingresistor shouldalwaysbeusedwithanLED.Theresistormustbechosentoyieldacurrentsuchthatanappropriatebrightnessisobtained.

220W

outputisHIGH

LEDandcurrent-limitingresistorusedtoindicateoutputlogiclevel

LEDlightswhen

Commonvaluesforcurrent-limitingresistors:200W,220W,270W,330W

Resistorcolorcoding

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Pleaseidentifyallresistorsinourlabkit.

Eachone’simage,anditsresistance,andputtheinformationinyourLab1report!

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ResistorColorCodeTheresistanceofcarbonresistorsisindicatedbycoloredbandsontheresistor.Thefirstthreebands(A,B,C)indicatethevalueoftheresistanceandthelastband(D)indicatesthetolerance.

ABCDR=ABx10C

A=FirstDigitB=SecondDigitC=NumberofZerosD=ToleranceCode

ValuesforBandsA,B,andC

ValuesforBandDGold– 5%toleranceSilver– 10%toleranceNone– 20%tolerance

Riscalculateusing:

Examples:Yellow,Violet,Brown,Silver:R=47x101 =470W,10%toleranceBrown,Black,Orange,Gold:R=10x103=10kW,5%tolerance

or