Lab 6physics

Lab 6physics - Lab6:Oscilloscope StaciWilliams

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Unformatted text preview: Lab6:Oscilloscope StaciWilliams NicoleHarty,KevinSchesing,CaitlinKubota Section015 Theory: Oscilloscopescanmeasurepropertiesofaperiodicvoltagesuchasshape,peakto peakamplitude,andperiod.Aslowlyvaryingperiodicvoltagecanbeobservedona voltagemeter,withaverticalaxisforvoltageandahorizontalaxisfortime.The intervalinwhichplottingoccursisP=t2t1,andfromt2untilt3foravalueoftime Nplottingdoesnotoccur.Atpointt3itisatthesamepointasVT,andwillstart beingplottedagainatthehorizontalaxispointt1,withthesecondplotting overlayingthefirstcurve,whichwouldfadeawayotherwise.Thisprocess continues,witheverytimetheplottingpaperstopsatt2itisresumedaftertimeNat t1whenthevoltagereachesthevalueVT.Whenhitbyelectronsthephosphor emitslightattheplacewheretheelectronsstrikethephosphor,allowingacurveto beseen,withthelightfadingawaywithtimeastheelectronsarenotcontinuously strikingit.OnesweepoftheelectronbeamacrossthephosphorisP,theelectron beamisshutoffforN,andVTisthetriggervoltage,orthevalueofthevoltagethat tellstheelectronbeamtostartatthebeginningofthecurve.Thehorizontaltime scaleisdependentuponhowfasttheelectronbeammovesacrossthephosphor,if thevoltagehasahighfrequencythetimebaseneedstosweepfastandviceversa.A cathoderayisabeamofelectrons,whicharethermallyemittedfromahotcathode, andareacceleratedandfocusedintoathinbeambyelectrostaticlenses,witha vacuumkeepingelectronstogether.Theelectronbeamispassedthroughtwo deflectionplates,oneforhorizontalandoneforvertical,andthenwillbeshownon theoutside,decayinginlessthanonesecond,leavingthetracebyrepetitively executingthesamepathonascreen. Lightisemittedwherethedeflectedelectricbeamstrikesaphosphormaterialthat coverstheinsideofthetube.Applyingatimedependentvoltagetothedeflection platescausesthebeamtomovearound,creatingthetrace. Data/Calculations/Questions/Information: 1Introduction Thesinewavefromthesignalgeneratorwasdistorted 6.1Preliminaries Thetracetravelsfromlefttotherightsideofthescreen,anditwilldisappearfora shortamountoftimeandthenreappearonthelefthandside.Turningthevariable sweeprateknobwillchangethespeedofthetraceacrossthescreen.Thetrace becomesasolidlineat1ms,anditflickersfrom2msto10ms. 6.2ObservingVoltageFromtheWavetekFG3CFunctionGenerator 1.WhentheVOLTS/DIVcontrolsarechangeditwillincrease/decreasethe amplitudesuchthatwhenthevoltagedecreasestheamplitudeincreases. 2.WhentheTIME/DIVcontrolsarechangedthewavelengthwillchange,withthe horizontalaxisstretchingifwelowertheTIME/DIV,andthehorizontalaxiswill narrowifweraisetheTIME/DIV. 3.Ifthetriggerlevelischangedaroundthetracewillbeinvertedatthesamevalues. 4.Itispossibleforthetracetodisappearonbothsides,becausethereisalevel wherethepulseisnolongerdetected,makingthetracedisappear. 5.Whenthetriggeringslopeischangedfromapositivetoanegativetherewillbea verticalreflectionwiththecurvebeingthesamehorizontally,butreflecteduponthe xaxis. 6.Thepositioncontrol17willcausemotionintheupanddowndirections,andthe positioncontrol27willcausemotionintheleftandrightdirections. 6.3OtherWaveformsandFunctions WhentheWavetekknobispulledoutitshiftsthepeak/troughtotheleft/right.The tracewillvaryfromACtoDCbecauseinACthecurrentvarieswithtime,andinDC thesignalwillbeconstantwithtimeandwhenweswitchahorizontallineappears torepresenttheaveragevoltage.WhenputbacktoACitrevertsbacktotheoriginal. DCbiascouldbecalculatedbycalculatingtheaverage. 6.5MeasuringWaveformParameters V=1.19 T=1ms f=995.72f=840.34 percenterror:995.72840.34/995.72*100%=15.6% 8AnalogversusDigitalScopes 2000samples/s t=1ms/div t=10ms 200samples/sweep Error: Littleerrorwasfoundbetweenthecalculatedfrequencyandthestatedfrequency throughSWS.Thiscouldbeduetohumanerrorincalculationsorevendueto equipmenterrorbetweenitandtheSWS. Conclusions: Anoscilloscopecanbeusedtoseevoltageasafunctionovertime,andallowedusto successfullyunderstandhowtousetheoscilloscope.Thislaballowedforusto becomefamiliarwiththedifferentknobsandfunctionsthatcanbeperformedusing theoscilloscope. ...
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