實驗指針萬用表的使用-Experiment Using t

實驗：指針萬用表的使用

Experiment:UsingtheAnalogMultimeter實訓目的TrainingObectives:學習認識萬用表的結構Understandthestructureofananalogmultimeter.01掌握指針式是萬用表的使用注意事項Learntheprecautionsforusingananalogmultimeter.0203掌握用萬用表測量電阻的方法Masterthemethodofmeasuringresistancewithamultimeter.1、MF-47指針式萬用表的結構I.StructureoftheMF-47AnalogMultimeter1-表筆插孔Probejacks2-晶體管插孔Transistorsocket3-讀數(shù)裝置（表頭）Readingdevice(meterhead)4-機械調(diào)零旋鈕Mechanicalzeroadjustmentknob

5-歐姆調(diào)零旋鈕Ohmszeroadjustmentknob6-擋位旋鈕Rangeselectorknob2.指針式萬用表的使用方法UsingtheAnalogMultimeter（1）使用前的檢查與調(diào)整InspectionandAdjustmentBeforeUse1.指針式萬用表的外觀應完好無損，在其輕輕搖晃時，指針應擺動自如。旋動擋位旋鈕，應切換靈活無卡阻，且擋位準確。Theanalogmultimetershouldbeingoodcondition,andthepointershouldmovefreelywhengentlyshaken.Rotatingtherangeselectorknobshouldswitchsmoothlywithoutsticking,andtherangesshouldbeaccurate.2.在測量前，先檢查紅、黑表筆插接的位置是否正確。紅表筆接紅色接線柱或標有“＋”的插孔內(nèi)，黑表筆接黑色接線柱或標有“－”的插孔內(nèi)。Beforemeasurement,checkiftheredandblacktestprobesarecorrectlyinserted.Theredtestprobeshouldbeconnectedtotheredterminalorthesocketlabeledwitha"+"symbol,whiletheblacktestprobeshouldbeconnectedtotheblackterminalorthesocketlabeledwitha"?"symbol.3.在紅、黑表筆接至被測電路前，務必查看所選擋位與測量對象是否相符，避免擋位和量程的誤用造成無法獲取測量結果，甚至損壞萬用表。Beforeconnectingtheredandblacktestprobestothecircuitundertest,verifythattheselectedrangematchesthemeasurementobject.Thispreventsincorrectrangeselectionandmisuse,whichcouldleadtoinaccuratemeasurementsordamagetothemultimeter.4.水平放置指針式萬用表，轉動表頭下方的機械調(diào)零旋鈕，使指針對準弧線刻線左邊的零位線，避免讀數(shù)出現(xiàn)較大的誤差。Placetheanalogmultimeterhorizontallyandrotatethemechanicalzeroadjustmentknoblocatedunderthemeterhead.Alignthepointerwiththezeroreferencelinetoavoidsignificantreadingerrors.2.指針式萬用表的使用方法UsingtheAnalogMultimeter5.測量電阻前，需經(jīng)由歐姆調(diào)零旋鈕實施調(diào)零操作（每換擋1次均應進行調(diào)零操作）。調(diào)零操作時，先將擋位旋鈕扳至歐姆擋適合位置，再使紅、黑表筆短接，轉動歐姆調(diào)零旋鈕，使指針對準歐姆刻線右邊的零位線。若指針始終不能指向零位線，則應更換萬用表的后備電池。Whenmeasuringresistance,performazeroadjustmentusingtheohmszeroadjustmentknob(performthisadjustmenteverytimeyouchangetherange).Todothis,settherangeselectorknobtotheappropriateohmsrange,short-circuittheredandblacktestprobes,andthenrotatetheohmszeroadjustmentknobuntilthepointeralignswiththezeroreferencelineontherightsideoftheohmsscale.Ifthepointerconsistentlyfailstopointtothezeroreferenceline,replacethebackupbatteryofthemultimeter.2.指針式萬用表的使用方法UsingtheAnalogMultimeter(2)萬用表使用方法(2)OperatingProceduresfortheMultimeter1.先水平放置萬用表，并機械調(diào)零。Placethemultimeterhorizontallyandperformthemechanicalzeroadjustment.2.根據(jù)測量參數(shù)要求，插入紅、黑表筆，黑表筆接入COM公用端，紅表筆接入＋、2500V、10A或mA插孔。Dependingonthemeasurementparameters,inserttheredandblacktestprobes.ConnecttheblacktestprobetotheCOMcommonterminalandtheredtestprobetothe+,2500V,10A,ormAsocket.3.選擇擋位及量程（電壓、電流或電阻等）。每選擇1次歐姆擋時，均應進行歐姆調(diào)零操作。Selecttheappropriaterangeandscale(voltage,current,orresistance,etc.).Zeroadjustmentshouldbeperformedeachtimetheohmsrangeisselected.2.指針式萬用表的使用方法UsingtheAnalogMultimeter4.將萬用表紅、黑表筆連接于被測電路中，注意串聯(lián)或并聯(lián)、直流參數(shù)的極性等。Connecttheredandblacktestprobestothecircuitundertest,payingattentiontotheseriesorparallelconnectionandthepolarityofDCparameters,ifapplicable.5.根據(jù)選擇的擋位及量程讀取數(shù)值。Readthevaluesbasedontheselectedrangeandscale.6.測量完畢，擋位旋鈕扳至交流電壓最大擋、空擋或OFF擋。若長時間不用，應取出內(nèi)部電池。Aftermeasurement,turntherangeselectorknobtothemaximumACvoltagerange,theoffposition,orOFF.Ifnotinuseforanextendedperiod,removetheinternalbattery.2.指針式萬用表的使用方法UsingtheAnalogMultimeter(3)電阻測量的關鍵步驟。(3)KeyStepsforResistanceMeasurement1.斷開被測電路的電源及連接導線。被測電阻所處電路務必斷電，并使之與其他元器件的連接導線斷開——即被測電阻不能存在并聯(lián)支路。Disconnectthepowersourceandconnectingwiresfromthecircuitundertest.Thecircuitcontainingtheresistortobemeasuredmustbede-energized,anditsconnectionswithothercomponentsshouldbedisconnected—meaningthattheresistortobemeasuredshouldnothaveanyparallelbranches.2.指針式萬用表的使用方法UsingtheAnalogMultimeter2.擋位及量程的選擇。先粗略估計所測電阻的阻值，再選擇合適的量程。若被測電阻不能估計其值，一般是將擋位旋鈕扳至R×100或R×1k的位置初測后，觀察指針是否停在歐姆刻度線中心值附近：是表示擋位合適，指針太靠零表示擋位需要減小，指針太靠無窮大（∞）表示擋位需要增大。SelectingtheRangeandScale.Initially,estimatetheapproximateresistancevaluetobemeasured,andthenchoosetheappropriatescale.Iftheresistancevaluecannotbeestimated,startbysettingtherangeselectorknobtotheR×100orR×1kposition.Observewhetherthepointerstopsnearthecentervalueoftheohmsscale:ifitdoes,itindicatesthecorrectrange;ifthepointeristooclosetozero,therangeneedstobedecreased,andifthepointeristooclosetoinfinity(∞),therangeneedstobeincreased.2.指針式萬用表的使用方法UsingtheAnalogMultimeter3.正確測量電阻。將量程選定且歐姆調(diào)零完畢的指針式萬用表的紅、黑表筆分別緊密接觸被測電阻的兩端，雙手不可同時觸至表筆的金屬部分及電阻被測端，以免引入的人體電阻造成較大的測量誤差。ProperResistanceMeasurement.Ensurethattherangeisselected,andtheohmszeroadjustmentiscomplete.Makesuretheredandblacktestprobesoftheanalogmultimetermakegoodcontactwiththetwoendsoftheresistorundertest.Avoidtouchingthemetalpartsofthetestprobesandthemeasuredterminalsoftheresistorsimultaneouslywithyourhandstopreventintroducingsignificantmeasurem