Kev xaiv ntau thiab ntsuas qhov tsis raug rau cov tsis kam
Txhua kab ntawm cov iav tiv thaiv tau tuaj yeem ntsuas qhov tseem ceeb ntawm 0 txog ∞. Qhov ntsuas ntawm ib tug ohmmeter muaj qhov tsis-} nteg thiab tsis sib xws inverted nplai. Nws yog qhia raws li feem pua ntawm kev ua siab ntev ntawm tus pas ntsuas. Thiab sab hauv kev tawm tsam ntawm txhua qhov yog sib npaug zos ntawm chaw nruab nrab ntawm cov nplai sib npaug los ntawm cov hmoov sib npaug, hu ua "Chaw Kuj". Uas yog hais, thaum ntsuas kev tawm tsam yog sib npaug ntawm qhov chaw tsis kam ntawm Circuit Court yog ib nrab ntawm cov nplai tam sim no. Lub pointer qhia nyob rau hauv nruab nrab ntawm nplai. Nws qhov tseeb yog qhia los ntawm cov kab sib luag hauv qab no:
R% {= (△ r / cenpus tiv taus) × 100%... 2
(1) Qhov yuam kev los ntawm kev xaiv ntau li ntau thaum ntsuas tib qho kev tawm tsam nrog tus multimeter
Piv txwv li, mf-30 pillateter muaj ib qho chaw tiv thaiv ntawm 250 ω hauv RXL0 ntau; Lub koom haum tsis kam ntawm R × l00 iav yog 2.5k ω. Qeb-qib yog 2.5. Siv nws los ntsuas tus qauv tiv thaiv ntawm 500 ω. Qhov twg yog qhov yuam kev loj tshaj plaws ntawm ntsuas nrog r × l0 iav thiab r × 100 iav? Kev daws: Los ntawm kab zauv 2:
R × l0 iav iav * loj * * Pub rau yuam kev △ r (10) {{{2} {{{{{5} {6.25 ω. Siv nws los ntsuas ib 500 ow stection resistance, tus nqi pom muaj nuj nqis ntawm 500 ω tus qauv tiv taus yog nruab nrab ntawm 493.75 ω. *The large relative error is: ± 6.25 ÷ 500 Ω× 100%=± 1.25%.
R × l00 iav * loj * * Siv nws los ntsuas ib 500 ow stection resistance, tus nqi pom muaj nuj nqis ntawm 500 ω tus qauv tiv taus yog nruab nrab ntawm 437.5 ω thiab 562.5 ω. * Cov txheeb ze loj yuam kev yog: ± 62.5 ÷ 500 ω × × € 100% {16} ± 10.5%.
Cov kev sib piv ntawm cov kev xam pom tau pom tias muaj kev ntsuas tsis raug thaum muaj kev xaiv txawv. Yog li ntawd, thaum xaiv cov iav ntau, nws yog ib qho tseem ceeb kom sim muab ntsuas ntsuas ntsuas ntawm qhov chaw ntawm lub arc ntev ntawm cov nplai. Qhov ntsuas qhov tseeb yog qhov siab dua.
