5 Cov Lus Qhia Ntsuas rau Digital Multimeters
1. Kuaj cov hais lus, lub mloog pob ntseg, thiab lub microphones dynamic:
Siv lub R × 1 Ω iav, txuas ib qho kev sojntsuam mus rau ib qho kawg thiab kov lwm qhov kev sojntsuam mus rau lwm qhov kawg. Raws li ib txwm muaj, lub suab "nias" yuav raug tso tawm. Yog tias nws tsis ua suab, nws txhais tau hais tias lub kauj tawg. Yog hais tias lub suab me me thiab ntse, nws txhais tau hais tias muaj teeb meem nrog so lub kauj thiab nws siv tsis tau.
2. Ntsuas capacitance:
Siv hom kev tiv thaiv, xaiv qhov tsim nyog raws li lub peev xwm capacitance, thiab xyuam xim rau kev sib txuas dub sojntsuam ntawm electrolytic capacitor rau qhov zoo electrode ntawm lub capacitor thaum ntsuas.
① Kev kwv yees lub peev xwm ntawm microwave capacitors: Nws tuaj yeem txiav txim siab raws li kev paub dhau los lossis los ntawm kev xa mus rau tus qauv capacitors ntawm tib lub peev xwm, raws li qhov siab tshaj plaws ntawm qhov taw tes oscillation. Lub capacitance raug xa mus tsis tas yuav tsum muaj qhov sib npaug nrog tus nqi hluav taws xob, tsuav yog qhov capacitance zoo ib yam. Piv txwv li, kwv yees lub peev xwm ntawm 100 μ F / 250V tuaj yeem hais nrog lub peev xwm ntawm 100 μ F / 25V. Ntev npaum li lawv lub pointer swings tib qhov siab tshaj plaws amplitude, nws tuaj yeem xaus lus tias qhov capacitance yog tib yam.
② Kev kwv yees lub peev xwm loj ntawm Pifa qib capacitor: Nws yog ib qho tsim nyog yuav tsum siv R × 10k Ω ntau, tab sis tsuas yog cov capacitors siab tshaj 1000pF tuaj yeem ntsuas tau. Rau cov capacitors ntawm 1000pF lossis loj me ntsis, tsuav yog lub pointer swings me ntsis, nws tuaj yeem txiav txim siab tias lub peev xwm txaus.
③ Ntsuas seb lub capacitor puas to: Rau cov capacitors siab tshaj 1000 microfarads, lawv tuaj yeem them sai sai siv R × 10 Ω ntau, thiab cov peev txheej tuaj yeem kwv yees pib. Tom qab ntawd, hloov mus rau R × 1k Ω ntau thiab txuas ntxiv ntsuas ib ntus. Thaum lub sijhawm no, tus taw tes yuav tsum tsis txhob rov qab los, tab sis yuav tsum nres ntawm lossis ze rau ∞, txwv tsis pub muaj qhov tshwm sim los. Rau qee lub sijhawm lossis oscillating capacitors hauv qab kaum ntawm microfarads (xws li oscillating capacitors hauv cov xim TV hloov hluav taws xob khoom siv), cov yam ntxwv xau siab heev. Tsuav muaj qhov to me ntsis, lawv siv tsis tau. Lub sijhawm no, lawv tuaj yeem raug them rau hauv R × 1k Ω ntau thiab tom qab ntawd hloov mus rau R × 10k Ω ntau los ntsuas txuas ntxiv. Ib yam li ntawd, tus taw tes yuav tsum nres ntawm ∞ thiab yuav tsum tsis txhob rov qab los.
3. Ntsuam xyuas qhov zoo ntawm diodes, transistors, thiab voltage regulators ntawm txoj kev:
Vim hais tias nyob rau hauv cov tswv yim circuits, qhov tsis zoo ntawm transistors los yog peripheral tsis kam ntawm diodes thiab voltage regulators feem ntau loj, feem ntau nyob rau hauv ntau pua los yog txhiab ohms ntau yam. Yog li ntawd, peb tuaj yeem siv R × 10 Ω lossis R × 1 Ω ntau ntawm cov khoom siv los ntsuas qhov zoo ntawm PN hlws ris hauv Circuit Court. Thaum ntsuas ntawm txoj kev, PN kev sib tshuam yuav tsum muaj cov yam ntxwv rau pem hauv ntej thiab thim rov qab thaum ntsuas hauv R × 10 Ω ntau yam (yog tias qhov sib txawv hauv pem hauv ntej thiab thim rov qab tsis tseem ceeb, R × 1 Ω ntau tuaj yeem siv rau kev ntsuas) . Feem ntau, qhov kev tiv thaiv rau pem hauv ntej yuav tsum qhia ib puag ncig 200 Ω thaum ntsuas hauv R × 10 Ω ntau, thiab nyob ib ncig ntawm 30 Ω thaum ntsuas hauv R × 1 Ω ntau yam (tej zaum yuav muaj qhov sib txawv me ntsis nyob ntawm qhov sib txawv phenotypes). Yog tias qhov ntsuas tau pom tias qhov kev tiv thaiv pem hauv ntej siab dhau los yog qhov rov qab ua haujlwm qis dhau, nws qhia tau tias muaj teeb meem nrog PN hlws ris, thiab lub raj kuj muaj teeb meem. Txoj kev no yog qhov tshwj xeeb tshaj yog rau kev saib xyuas, vim nws tuaj yeem txheeb xyuas cov kav dej tsis zoo thiab txawm tias pom cov kav dej uas tsis tawg tag tab sis muaj cov yam ntxwv tsis zoo. Piv txwv li, thaum koj ntsuas qhov kev tiv thaiv rau pem hauv ntej ntawm PN hlws ris nrog qhov tsis tshua muaj kev tiv thaiv ntau thiab nws siab dhau lawm, yog tias koj muab nws thiab ntsuas nws dua nrog cov R × 1k Ω feem ntau siv, nws tseem yuav yog qhov qub. Qhov tseeb, cov yam ntxwv ntawm cov raj no tau ua tsis zoo thiab nws tsis tuaj yeem ua haujlwm zoo lossis tsis ruaj khov.
