Cov haujlwm tshwj xeeb thiab kev siv ntawm multimeters yog raws li hauv qab no
Puas yog digital multimeter yuav tsum zoo dua li analog multimeter?
Kev daws: Digital multimeters tau siv sai sai vim lawv qhov zoo tshaj plaws xws li siab precision thiab rhiab heev, ntsuas ceev ceev, ntau lub zog, me me, siab input impedance, kev soj ntsuam yooj yim, thiab kev sib txuas lus muaj zog. Muaj ib qho kev hloov pauv ntawm cov ntsuas ntsuas ntsuas analog.
Tab sis nyob rau qee qhov xwm txheej, xws li cov muaj zog electromagnetic cuam tshuam, cov ntaub ntawv kuaj nrog digital multimeter yuav muaj qhov sib txawv tseem ceeb vim tias cov input impedance ntawm digital multimeter siab thiab yooj yim cuam tshuam los ntawm induced peev xwm.
Thaum lub sij hawm tu, nws xav tias los ntawm kev daws teeb meem tias lub diode lossis transistor hauv Circuit Court yuav puas. Tab sis siv lub ntsuas hluav taws xob digital diode los ntsuas nws qhov hluav taws xob conduction yog li ntawm 0.6V, uas yog infinite nyob rau hauv thim rov qab. Tsis muaj teeb meem, txawm tias tom qab kuaj xyuas Circuit Court dua, tsis pom qhov ua txhaum. Vim li cas?
Kev daws: Feem ntau cov ntsuas hluav taws xob tso tawm qhov ntsuas hluav taws xob txog li 3-4.5V los ntawm hom diode. Yog hais tias lub transistor kuaj tau me ntsis to los yog tus yam ntxwv nkhaus tau deteriorated, nws tsis tuaj yeem tso tawm ntawm qhov tsis tshua muaj hluav taws xob. Hauv qhov no, koj yuav tsum siv lub ntsuas ntsuas analog nrog 10K tsis kam. Qhov ntsuas hluav taws xob tsim los ntawm qhov ntau yam no yog 10V lossis 15V, thiab ntawm qhov ntsuas hluav taws xob no, nws yuav pom tias qhov xav tias transistor tau xau hauv qhov rov qab. Ib yam li ntawd, thaum ntsuas qhov tsis kam ntawm qee qhov ntsuas qhov ntsuas qhov ntsuas nrog qhov tsis tshua muaj hluav taws xob, siv lub ntsuas ntsuas analog tuaj yeem ua rau puas tsuaj rau cov khoom rhiab heev. Hauv qhov no, lub ntsuas hluav taws xob digital yuav tsum tau siv los ntsuas.
3. Siv ib qho multimeter los ntsuas tus nqi voltage tom qab lub attenuation ntawm high-voltage sojntsuam, nws tau pom tias qhov kev ntsuam xyuas DCV yog qhov tseeb dua, tab sis ACV yuam kev yog qhov tseem ceeb. Txawm tias thaum siv multimeter nrog high precision, vim li cas nws tseem zoo li qub?
Kev daws: Feem ntau ntawm cov khoom siv multimeters siv cov kev sib txuas sib txuas los ntsuas qhov ntsuas hluav taws xob, thiab rau tag nrho cov kev ntsuas hluav taws xob, lub voltmeter nws tus kheej yog sib npaug rau cov load uas yog cov input impedance. Qhov loj dua qhov impedance ntawm qhov load no, qhov me me ntawm qhov kev sim ntsuas Circuit Court, thiab qhov ntsuas qhov tseeb dua yuav yog. Tab sis tsis muaj dab tsi tuaj yeem ua tau zoo tag nrho, siab impedance txhais tau tias kev txi lub bandwidth ntawm qhov kev xeem. Tam sim no, cov input impedance ntawm multimeters nrog ib tug zaus teb ntawm ib ncig ntawm 100KHz nyob rau hauv lub lag luam yog nyob ib ncig ntawm 1.1M, yog li nws yuav muaj kev cuam tshuam tseem ceeb rau kev ntsuam xyuas qhov voltage ntawm ob kawg ntawm high-resistance loads, xws li cov high-resistance. high-voltage sojntsuam nws tus kheej. Nyob rau ntawm lub sijhawm no, koj yuav tsum xaiv lub siab nyob sab hauv multimeter, xws li ESCORT 170/172/176/178/179 handheld digital multimeter, uas muab cov input impedance txog li 10000 Ω thaum kuaj ACV, txhawm rau zam qhov no. teeb meem.
Hauv kev sim tiag tiag, kuv yuav tsum ntsuas tsis yog qhov voltage thiab tam sim no, impedance ntawm lub cev muaj zog windings, tab sis kuj ceev. Puas muaj multimeter uas tuaj yeem ua tiav qhov haujlwm no?
Kev daws: ESCORT (Fugui) -172 handheld digital multimeter tuaj yeem ua tau raws li koj cov kev xav tau saum toj no, thiab nws cov cai tswj kev nyab xeeb raws li International Electrotechnical Commission IEC1010-1 CATII 1000V thiab CATIII 600V cov qauv, yog li koj tuaj yeem siv nws nrog kev ntseeg siab txawm tias nyob rau hauv chav kawm III ib puag ncig yam tsis muaj kev txhawj xeeb txog teeb meem kev nyab xeeb.
