Taw qhia rau qhov tseeb ntawm Digital Multimeters
Qhov tseeb yog hais txog qhov ua yuam kev siab tshaj plaws uas tshwm sim hauv ib puag ncig kev siv tshwj xeeb. Hauv lwm lo lus, qhov tseeb yog siv los qhia
Qhov ze ntawm qhov ntsuas tus nqi ntawm ib qho digital multimeter thiab tus nqi tiag tiag ntawm cov teeb liab ntsuas.
Rau ib qho digital multimeter, qhov tseeb feem ntau yog qhia raws li feem pua ntawm kev nyeem ntawv. Piv txwv li, kev nyeem ntawv qhov tseeb ntawm 1% txhais tau hais tias thaum lub digital multimeter qhia 100.0V, qhov tseeb voltage yuav nyob nruab nrab ntawm 99.0V thiab 101.0V.
Cov txiaj ntsig tshwj xeeb tuaj yeem raug ntxiv rau qhov tseeb hauv cov lus qhia ntxaws. Nws lub ntsiab lus yog ntxiv tus naj npawb ntawm cov lus los hloov txoj cai kawg ntawm cov zaub. Hauv qhov piv txwv dhau los, qhov tseeb yuav raug cim tias ± (1%+2). Yog li, yog tias GMM nyeem ntawv yog 100.0V, qhov tseeb voltage yuav nyob nruab nrab ntawm 98.8V thiab 101.2V.
Qhov tseeb ntawm analog meter yog xam raws li qhov yuam kev ntawm tag nrho cov ntau yam, es tsis yog cov ntawv nyeem. Qhov raug raug ntawm ib qho analog meter yog ± 2% lossis ± 3% ntawm tag nrho cov ntau yam. Qhov tseeb qhov tseeb ntawm ib qho digital multimeter yog nyob nruab nrab ntawm ± (0.7%+1) thiab ± (0.1%+1) ntawm kev nyeem ntawv, lossis ntau dua .
Introduction to Resistance of Digital Multimeters
Ntsuas qhov tsis kam nyob rau hauv qhov kev tawm tsam. Tus nqi kuj txawv heev, xws li los ntawm ob peb milliohms (m Ω) ntawm kev tiv thaiv kev tiv thaiv mus rau billions ntawm ohms ntawm rwb thaiv tsev tsis kam. Ntau cov multimeters ntsuas qhov tsis kam qis li 0.1 ohms, thiab qee qhov kev ntsuas yuav siab li 300 megaohms (300000 ohms). Qhov kev tiv thaiv siab heev, Fluke multimeter yuav tso saib "OL", qhia tias qhov ntsuas tsis kam tshaj qhov ntau. Thaum ntsuas qhov qhib Circuit Court, nws yuav tso saib "OL".
Qhov kev tiv thaiv yuav tsum tau ntsuas nrog lub zog hluav taws xob tua hluav taws xob, txwv tsis pub yuav muaj kev puas tsuaj rau lub ntsuas hluav taws xob lossis lub rooj tsav xwm hauv Circuit Court. Qee cov digital multimeters muab kev tiv thaiv nyob rau hauv cov ntaub ntawv ntawm yuam kev txuas cov teeb liab voltage hauv hom resistive. Cov qauv sib txawv ntawm digital multimeters muaj peev xwm tiv thaiv sib txawv.
Thaum ua cov kev ntsuas qhov tseeb ntawm qhov tsis muaj zog, qhov tsis kam ntawm cov hlau ntsuas yuav tsum tau muab rho tawm los ntawm tus nqi ntsuas. Tus nqi tsis kam ntawm ib qho kev xeem xaim yog nyob nruab nrab ntawm {{0}}.2 Ω thiab 0.5 Ω. Yog tias qhov ntsuas tus nqi ntawm cov hlau ntsuas ntau dua 1 Ω, qhov ntsuas hlau yuav tsum tau hloov.
Yog tias lub tshuab hluav taws xob digital muab qhov hluav taws xob DC tsawg dua 0.6V rau kev ntsuas qhov tsis kam, nws tuaj yeem ntsuas qhov ntsuas tus nqi sib cais los ntawm diodes lossis semiconductors ntawm lub rooj tsavxwm. Yog li hais tias qhov kev tiv thaiv tuaj yeem kuaj tsis tau raug tshem tawm.
