Cov cuab yeej siv thiab xaiv cov qauv ntawm multimeter
Digital multimeter tam sim no yog cov cuab yeej siv digital tshaj plaws. Nws cov yam ntxwv tseem ceeb yog qhov raug siab, muaj zog daws teeb meem, kev ua haujlwm zoo tshaj plaws, ntsuas kev ceev ceev, cov khoom siv nkag siab, muaj peev xwm lim dej, tsis muaj zog noj, thiab nqa tau yooj yim. Txij li thaum xyoo 1990, digital multimeters tau nrov nrov thiab dav siv hauv kuv lub teb chaws, thiab tau dhau los ua cov cuab yeej tsim nyog rau kev ntsuas hluav taws xob niaj hnub thiab kev saib xyuas, thiab maj mam hloov cov tshuaj analog (ie, pointer) multimeters.
Digital multimeters tseem hu ua digital multimeters (DMMs), thiab muaj ntau hom thiab qauv. Txhua tus neeg ua haujlwm hauv hluav taws xob cia siab tias yuav muaj qhov zoo tshaj plaws digital multimeter. Muaj ntau lub hauv paus ntsiab lus rau kev xaiv digital multimeter, thiab qee zaum lawv kuj txawv ntawm ib tus neeg mus rau lwm tus. Txawm li cas los xij, rau lub hnab nqa khoom (lub hnab tshos) digital multimeter, feem ntau nws yuav tsum muaj cov yam ntxwv hauv qab no: cov duab meej, qhov tseeb siab, muaj zog daws teeb meem, kev sim ntau yam, ua tiav cov haujlwm, muaj peev xwm tiv thaiv kev cuam tshuam, ua tiav kev tiv thaiv Circuit Court, thiab zoo nkauj tsos. , siab dav, yooj yim rau kev khiav lag luam, yoog raws, kev ntseeg tau zoo, kev siv hluav taws xob tsawg, yooj yim nqa, tus nqi nruab nrab thiab lwm yam.
Cov cim tseem ceeb, tso saib cov lej thiab cov yam ntxwv ntawm cov digital multimeter
Cov lej tso saib ntawm lub tshuab ntsuas digital feem ntau yog {{0}}/2 rau 8 1/2 tus lej. Muaj ob lub hauv paus ntsiab lus rau kev txiav txim cov lej ntawm cov cuab yeej digital: ib qho yog tias cov lej uas tuaj yeem pom txhua tus lej ntawm 0 mus rau 9 yog tus lej lej; Tus lej yog tus lej, thiab suav tus nqi yog 2000 thaum siv tag nrho cov nplai, uas qhia tau tias qhov ntsuas muaj 3 tus lej lej, thiab tus lej ntawm tus lej feem ntau yog 1, thiab tus denominator yog 2, yog li nws yog hu ua 3 1/2 tus lej, nyeem raws li "peb thiab ib nrab tus lej", qhov siab tshaj plaws tsuas tuaj yeem tso saib 0 lossis 1 (0 feem ntau tsis tso tawm). 3 2/3 tus lej (hais tias "peb thiab ob feem peb tus lej"), tus lej siab tshaj plaws ntawm digital multimeter tsuas tuaj yeem tso saib tus lej ntawm 0 txog 2, yog li qhov siab tshaj plaws ntawm cov zaub yog ± 2999. Raws li cov xwm txheej zoo ib yam, nws yog 50 feem pua siab tshaj qhov txwv ntawm 3 1/2 tus lej digital multimeter, uas yog qhov tseem ceeb tshwj xeeb tshaj yog thaum ntsuas 380V AC voltage.
Nrov digital multimeters feem ntau yog cov handheld multimeters nrog 3 1/2 tus lej zaub, thiab 4 1/2, 5 1/2 tus lej (tsawg dua 6 tus lej) digital multimeters muab faib ua ob hom: handheld thiab desktop. Ntau tshaj 6 1/2 tus lej feem ntau yog rau desktop digital multimeters.
Lub multimeter digital tau txais cov thev naus laus zis thev naus laus zis thev naus laus zis, nrog cov duab pom tseeb thiab nkag siab thiab nyeem tau raug. Nws tsis tsuas yog ua kom lub hom phiaj ntawm kev nyeem ntawv, tab sis kuj ua raws li tib neeg txoj kev nyeem ntawv, thiab tuaj yeem ua kom luv luv nyeem ntawv lossis kaw lub sijhawm. Cov txiaj ntsig no tsis muaj nyob rau hauv cov tshuaj analog (piv txwv li pointer) multimeters.
Qhov tseeb (precision)
Qhov tseeb ntawm digital multimeter yog kev sib xyaw ua ke ntawm cov txheej txheem tsis raug thiab qhov yuam kev random hauv cov txiaj ntsig ntsuas. Nws qhia txog qib kev pom zoo ntawm tus nqi ntsuas thiab tus nqi tseeb, thiab tseem qhia txog qhov loj ntawm qhov ntsuas qhov yuam kev. Feem ntau hais lus, qhov raug siab dua, qhov me me ntawm qhov ntsuas qhov yuam kev, thiab rov ua dua.
Qhov tseeb ntawm cov multimeters yog zoo dua li cov analog analog multimeters. Qhov tseeb ntawm multimeter yog qhov taw qhia tseem ceeb heev. Nws qhia txog qhov zoo thiab kev muaj peev xwm ntawm multimeter. Nws yog ib qho nyuaj rau ib tug multimeter nrog cov neeg tsis zoo los qhia tus nqi tiag tiag, uas yuav yooj yim ua rau kev txiav txim siab tsis zoo hauv kev ntsuas.
Kev daws teeb meem (resolution)
Tus nqi hluav taws xob sib raug rau tus lej kawg ntawm cov digital multimeter ntawm qhov qis tshaj qhov voltage yog hu ua kev daws teeb meem, uas qhia txog qhov rhiab heev ntawm lub 'meter'. Qhov kev daws teeb meem ntawm cov cuab yeej digital nce nrog kev nce ntawm cov lej tso saib. Cov kev daws teeb meem siab tshaj plaws uas digital multimeters nrog tus lej sib txawv tuaj yeem ua tiav yog qhov sib txawv.
Qhov kev daws teeb meem ntawm digital multimeter kuj tuaj yeem pom los ntawm kev daws teeb meem. Kev daws teeb meem yog qhov feem pua ntawm tus lej tsawg tshaj plaws (tshwj tsis yog xoom) uas lub ntsuas ntsuas tuaj yeem tso rau tus lej loj tshaj plaws.
Nws yuav tsum tau taw qhia tias kev daws teeb meem thiab qhov tseeb yog ob lub ntsiab lus sib txawv. Tus qub cim qhov "rhiab heev" ntawm qhov ntsuas, uas yog, muaj peev xwm "paub" me me voltages; qhov tom kawg qhia txog qhov "qhov tseeb" ntawm kev ntsuas, uas yog, qib ntawm qhov sib xws ntawm qhov ntsuas qhov tshwm sim thiab tus nqi tseeb. Tsis muaj kev sib txuas tsim nyog ntawm ob, yog li lawv tsis tuaj yeem tsis meej pem, thiab kev daws teeb meem (lossis kev daws teeb meem) yuav tsum tsis txhob yuam kev rau qhov zoo sib xws. Qhov tseeb yog nyob ntawm qhov kev ua yuam kev loj thiab qhov yuam kev quantization ntawm lub internal A/D converter thiab functional converter ntawm lub ntsuas. Los ntawm qhov kev xav ntawm kev ntsuas, kev daws teeb meem yog qhov ntsuas "virtual" (uas tsis muaj dab tsi cuam tshuam nrog kev ntsuas qhov yuam kev), thiab qhov tseeb yog qhov ntsuas "tiag tiag" (nws txiav txim siab qhov loj ntawm kev ntsuas qhov yuam kev). Yog li ntawd, nws yog tsis muaj peev xwm mus arbitrarily nce tus naj npawb ntawm cov zaub cov lej los txhim kho qhov kev daws teeb meem ntawm qhov ntsuas.
Kev ntsuas ntau
Nyob rau hauv lub multi-function digital multimeter, cov haujlwm sib txawv muaj lawv qhov sib thooj siab tshaj plaws thiab qhov tsawg kawg nkaus uas tuaj yeem ntsuas tau.
Ntsuas tus nqi
Tus naj npawb ntawm lub sij hawm digital multimeter ntsuas qhov ntsuas hluav taws xob ib ob yog hu ua qhov ntsuas ntsuas, thiab nws chav tsev yog "times / s". Nws tsuas yog nyob ntawm tus nqi hloov pauv ntawm A / D converter. Qee lub xov tooj ntawm tes digital multimeters siv lub sijhawm ntsuas los qhia qhov ceev ntawm kev ntsuas. Lub sijhawm yuav tsum ua kom tiav cov txheej txheem ntsuas yog hu ua lub voj voog ntsuas.
Muaj qhov tsis sib xws ntawm qhov ntsuas ntsuas thiab qhov ntsuas qhov tseeb. Feem ntau, qhov siab dua qhov tseeb yog, qhov ntsuas qis dua yog, thiab nws nyuaj rau sib npaug ntawm ob. Txhawm rau daws qhov tsis sib xws, koj tuaj yeem teeb tsa cov lej sib txawv lossis teeb tsa qhov ntsuas nrawm hloov pauv hauv tib lub ntsuas ntsuas: ntxiv cov ntaub ntawv ntsuas ceev, uas yog siv rau A / D converter nrog qhov ntsuas nrawm dua; Txhawm rau nce tus nqi ntsuas, txoj kev no kuj muaj ntau thiab tuaj yeem ua tau raws li qhov xav tau ntawm cov neeg siv sib txawv rau qhov ntsuas ntsuas.
input tsis kam
Thaum ntsuas qhov ntsuas hluav taws xob, lub ntsuas yuav tsum muaj qhov kev tawm tswv yim siab heev, yog li qhov tam sim no rub los ntawm Circuit Court nyob rau hauv kev ntsuas me me thaum lub sijhawm ntsuas, uas yuav tsis cuam tshuam rau kev ua haujlwm ntawm Circuit Court hauv kev sim lossis lub teeb liab, thiab tuaj yeem txo qhov ntsuas qhov yuam kev.
Thaum ntsuas tam sim no, lub ntsuas yuav tsum muaj qhov cuam tshuam qis heev, kom lub zog ntawm lub ntsuas hluav taws xob hauv Circuit Court nyob rau hauv kev sim tuaj yeem raug txo kom ntau li ntau tau tom qab txuas rau hauv Circuit Court hauv kev sim. Hlawv tawm lub 'meter', thov xyuam xim thaum siv nws.
Kev faib tawm ntawm digital multimeters
Digital multimeters raug cais raws li kev hloov pauv ntau yam, uas tuaj yeem muab faib ua peb hom: phau ntawv ntau yam (MAN RANGZ), tsis siv neeg ntau yam (AUTO RANGZ), thiab tsis siv neeg / phau ntawv ntau (AUTO / MAN RANGZ).
Raws li kev ua haujlwm sib txawv, kev siv thiab tus nqi, digital multimeters tuaj yeem faib ua 9 pawg: low-end digital multimeters (tseem hu ua digital multimeters), mid-range digital multimeters, nruab nrab / high-end digital multimeters, digital / analog. hybrid instruments, digital Instrument with dual display of /analog diagram, multi-purpose oscilloscope (integrating digital multi-meter, digital storage oscilloscope and other kinetic zog into one body).
Kev ntsuas kev ua haujlwm ntawm digital multimeter
Cov multimeter tsis tuaj yeem ntsuas DC voltage (DCV), AC voltage (ACV), DC tam sim no (DCA), AC tam sim no (ACA), tsis kam (Ω), diode rau pem hauv ntej voltage poob (VF), transistor emitter tam sim no amplification yam ( hrg), kuj tseem tuaj yeem ntsuas qhov capacitance (C), conductance (ns), qhov kub thiab txias (T), zaus (f), thiab ntxiv cov ntaub ntawv buzzer (BZ) rau kev kuaj xyuas qhov txuas ntxiv ntawm kab, txoj kev siv hluav taws xob tsawg los ntsuas cov ntaub ntawv tiv thaiv ( L0Ω). Qee cov twj paj nruag kuj muaj inductance iav, teeb liab iav, AC / DC tsis siv neeg hloov dua siab tshiab muaj nuj nqi, thiab capacitance iav tsis siv neeg ntau yam hloov pauv.
Feem ntau cov digital digital multimeters ntxiv cov haujlwm tshiab thiab cov tswv yim hauv qab no: nyeem ntawv tuav (TSH), ntsuas kev ntsuas (LOGIC), qhov muaj txiaj ntsig zoo (TRMS), ntsuas tus nqi txheeb ze (RELΔ), tsis siv neeg kaw (AUTO OFF POWER), thiab lwm yam.
Lub peev xwm tiv thaiv kev cuam tshuam ntawm digital multimeter
Tej yam yooj yim digital multimeters feem ntau txais yuav ib qho tseem ceeb ntawm A / D hloov txoj hauv kev. Ntev npaum li lub sijhawm sib xyaw ua ke zoo raug xaiv kom sib npaug ntawm qhov sib npaug ntawm ntau lub sijhawm ntawm cov teeb liab cuam tshuam cuam tshuam, qhov cuam tshuam ntawm cross-frame tuaj yeem cuam tshuam zoo. Qhov no yog vim hais tias tus ntoo khaub lig-nruab nrab cuam tshuam teeb liab yog nruab nrab tawm nyob rau hauv pem hauv ntej integration theem. Qhov sib piv piv txwv tsis lees paub (CMRR) ntawm nruab nrab thiab qis-kawg digital multimeters tuaj yeem ncav cuag 86-120dB.
Txoj kev loj hlob ntawm digital multimeter
Kev sib xyaw ua ke: Lub handheld digital multimeter siv ib-chip A / D converter, thiab peripheral Circuit Court yog qhov yooj yim, tsuas yog yuav tsum muaj tsawg tsawg ntawm cov chips thiab cov khoom siv. Nrog rau qhov kev tshwm sim tas mus li ntawm cov chips siab rau ib leeg-chip digital multimeters, ib qho kev ua haujlwm tsis siv neeg ntau yam digital multimeter tuaj yeem tsim los siv ib leeg IC, uas tsim cov kev pom zoo rau kev yooj yim tsim thiab txo cov nqi.
Kev siv hluav taws xob tsawg: Cov khoom siv digital tshiab feem ntau siv CMOS loj-teev kev sib txuas ntawm A / D converters, thiab lub zog siv ntawm tag nrho lub tshuab yog tsawg heev.
Kev sib piv ntawm qhov zoo thiab qhov tsis zoo ntawm cov multimeters zoo tib yam thiab digital multimeters:
Ob lub pointer thiab digital multimeters muaj lawv tus kheej qhov zoo thiab qhov tsis zoo.
Tus pointer multimeter yog qhov ntsuas nruab nrab, uas muaj qhov ntsuas kev nyeem ntawv zoo thiab pom tseeb. (Qhov kev nyeem ntawv dav dav yog ze ze rau lub viav vias lub kaum sab xis ntawm lub pointer, yog li nws yog intuitive heev).
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Digital multimeter yog ib qho ntsuas ntsuas tam sim. Nws yuav siv ib qho piv txwv txhua txhua 0.3 vib nas this los tso saib cov txiaj ntsig ntsuas, thiab qee zaum cov txiaj ntsig ntawm txhua qhov piv txwv zoo sib xws, tsis zoo ib yam, uas tsis yooj yim npaum li tus taw tes rau kev nyeem cov txiaj ntsig. Tus pointer multimeter feem ntau tsis muaj lub suab nrov sab hauv, yog li kev ua haujlwm sab hauv me me.
Txij li thaum lub tshuab hluav taws xob digital siv lub tshuab hluav taws xob ua haujlwm sab hauv, qhov kev tiv thaiv sab hauv tuaj yeem ua kom loj, feem ntau 1M ohm lossis loj dua. (piv txwv li qhov siab dua tuaj yeem tau txais). Qhov no ua rau qhov cuam tshuam ntawm Circuit Court nyob rau hauv kev sim yuav me me, thiab qhov ntsuas qhov tseeb yog siab dua.
Vim qhov me me sab hauv tsis kam ntawm tus pointer multimeter, thiab siv cov khoom sib cais los ua ib qho shunt thiab voltage divider circuit. Yog li, cov yam ntxwv zaus tsis sib xws (piv rau hom digital), thiab cov yam ntxwv zaus ntawm digital multimeter kuj zoo dua.
Cov qauv sab hauv ntawm lub pointer multimeter yog qhov yooj yim, yog li tus nqi qis, kev ua haujlwm tsawg tsawg, kev saib xyuas yooj yim, thiab lub peev xwm overcurrent thiab overvoltage muaj zog.
Digital multimeter siv ntau yam oscillation, amplification, zaus division tiv thaiv thiab lwm yam circuits sab hauv, yog li nws muaj ntau lub zog. Piv txwv li, koj tuaj yeem ntsuas qhov kub thiab txias, zaus (hauv qhov qis dua), capacitance, inductance, ua lub teeb liab generator, thiab lwm yam.
Txij li cov qauv sab hauv ntawm cov digital multimeter feem ntau siv cov kev sib xyaw ua ke, lub peev xwm dhau los kuj tsis zoo, thiab feem ntau tsis yooj yim kho tom qab kev puas tsuaj. DMMs muaj qhov tso zis tsawg voltages (feem ntau tsis tshaj 1 volt). Nws tsis yooj yim rau kev sim qee yam khoom siv nrog cov yam ntxwv tshwj xeeb (xws li thyristors, lub teeb-emitting diodes, thiab lwm yam). Tus pointer multimeter muaj qhov tso zis ntau dua. Tam sim no kuj loj, thiab nws yooj yim rau kev sim thyristors, lub teeb-emitting diodes, thiab lwm yam.
Ib tug pointer multimeter yuav tsum tau siv rau beginners, thiab ob hom meters yuav tsum tau siv rau cov tsis pib.
xaiv txoj cai
1. Kev nyeem ntawv qhov tseeb ntawm lub ntsuas ntsuas ntsuas yog qhov tsis zoo, tab sis cov txheej txheem ntawm lub viav vias pointer yog qhov xav tau ntau dua, thiab nws qhov viav vias nrawm tuaj yeem qee zaum cuam tshuam txog qhov loj ntawm qhov ntsuas (xws li ntsuas me ntsis jitter); Kev nyeem ntawv ntawm lub ntsuas ntsuas digital yog qhov xav tau, tab sis cov txheej txheem ntawm kev hloov pauv digital zoo li ntxhov thiab tsis yooj yim saib.
2. Feem ntau, muaj ob lub roj teeb nyob rau hauv lub pointer saib, ib qho yog tsawg voltage 1.5V, lwm yam yog high voltage 9V los yog 15V, thiab cov dub xeem lead yog qhov zoo kawg uas txheeb ze rau cov liab xeem lead. Cov ntsuas hluav taws xob feem ntau siv 6V lossis 9V roj teeb. Nyob rau hauv cov ntaub ntawv tsis kam, cov zis tam sim no ntawm tus cwj mem ntsuas ntawm lub ntsuas ntsuas ntsuas yog qhov loj dua li ntawm cov ntsuas digital. Cov ntaub ntawv R × 1Ω tuaj yeem ua kom lub suab nrov ua suab nrov "da", thiab cov ntaub ntawv R × 10kΩ tuaj yeem ua rau lub teeb pom kev zoo (LED).
3. Nyob rau hauv qhov hluav taws xob ntau, qhov kev tiv thaiv sab hauv ntawm lub ntsuas ntsuas ntsuas yog qhov me me piv nrog cov ntsuas digital, thiab qhov ntsuas qhov tseeb yog qhov tsis zoo. Qee lub sijhawm uas muaj qhov hluav taws xob siab thiab micro tam sim no tsis tuaj yeem ntsuas qhov tseeb, vim tias nws qhov kev tiv thaiv sab hauv yuav cuam tshuam rau Circuit Court hauv kev sim (piv txwv li, thaum ntsuas qhov nrawm theem voltage ntawm lub raj duab TV, qhov ntsuas tus nqi yuav qis dua qhov tseeb. tus nqi). Qhov kev tiv thaiv sab hauv ntawm qhov ntsuas hluav taws xob ntawm lub ntsuas hluav taws xob yog qhov loj heev, yam tsawg kawg hauv megohm theem, thiab muaj kev cuam tshuam me me rau hauv Circuit Court hauv kev sim. Txawm li cas los xij, qhov tso zis ntau dhau impedance ua rau nws raug cuam tshuam rau qhov cuam tshuam ntawm qhov hluav taws xob induced, thiab cov ntaub ntawv ntsuas yuav tsis raug nyob rau qee lub sijhawm uas muaj zog electromagnetic cuam tshuam.
4. Nyob rau hauv luv luv, pointer meters yog haum rau kev ntsuas ntawm analog circuits nrog cov tam sim no thiab high voltage, xws li TV teeb thiab suab amplifiers. Nws yog qhov tsim nyog rau cov ntsuas hluav taws xob hauv kev ntsuas cov hluav taws xob qis thiab qis tam sim no digital circuits, xws li BP tshuab, xov tooj ntawm tes, thiab lwm yam. Nws tsis yog qhov tseeb, thiab cov lus taw qhia thiab cov rooj digital tuaj yeem xaiv tau raws li qhov xwm txheej.
