Tsab xov xwm hais txog hluav taws xob tam sim no tau tham txog qhov ceev ntawm hluav taws xob tam sim no, thiab lub tshav fais fab kuj tau piav qhia hauv tsab xov xwm hais txog hluav taws xob. Lub tshav fais fab thiab hluav taws xob tam sim no muaj nyob hauv tus neeg coj hluav taws xob thaum muaj qhov sib txawv ntawm lub zog hla tus neeg coj hluav taws xob; ntawm qhov tod tes, yog tias tsis muaj qhov sib txawv ntawm lub zog, tsis muaj lub tshav fais fab lossis hluav taws xob tam sim no.
Hauv ib lub hlau conductor, lub teb hluav taws xob yog ncaj qha proportional rau qhov ceev tam sim no, qhov twg qhov piv ntawm lub teb hluav taws xob rau qhov ceev tam sim no yog qhov tsis hloov pauv. Qhov piv ntawm lub teb hluav taws xob rau qhov ceev tam sim no hu ua resistivity lossis kev tiv thaiv tshwj xeeb . Mathematically, kev sib raug zoo ntawm lub teb hluav taws xob, qhov ceev tam sim no, thiab kev tiv thaiv tshwj xeeb yog qhia hauv kab zauv:
Kev piav qhia: ρ = kev tiv thaiv tshwj xeeb, E = lub zog hluav taws xob, J = qhov ceev tam sim no
Ib qho ntawm cov qauv hluav taws xob yog E = V/s qhov twg V = qhov sib txawv ntawm lub zog hluav taws xob = hluav taws xob voltage thiab s = nrug, yog li chav tsev ntawm lub zog hluav taws xob yog Volt/meter (V/m). Cov qauv ceev tam sim no yog J = I/A qhov twg I = hluav taws xob tam sim no thiab A = thaj tsam hla ntawm tus neeg coj, yog li chav tsev ntawm qhov ceev tam sim no yog Ampere/meter squared (A/m2 ) . Cov qauv resistivity yog ρ = E/J yog li chav tsev ntawm kev tiv thaiv yog V/m: A/m2 = V/mxm2 / A = V/A (m) = Ω m (nyeem: Ohm meter). Ω = Volt/Ampere yog chav tsev ntawm kev tiv thaiv hluav taws xob, hais txog chav tsev no tau piav qhia hauv tsab xov xwm txog Ohm txoj cai.
Cov nqi resistivity siab tshaj plaws yog muaj los ntawm cov insulators hluav taws xob lossis cov neeg ua hluav taws xob tsis zoo, thaum cov nqi resistivity qis tshaj plaws yog muaj los ntawm cov neeg ua hluav taws xob lossis cov neeg ua hluav taws xob zoo. Qhov zoo dua tus neeg ua hluav taws xob coj hluav taws xob tam sim no, qhov qis dua nws qhov resistivity . Qhov kev txiav txim ntawm cov hlau conductors nrog qhov siab tshaj plaws mus rau qhov qis tshaj resistivity yog tin, hlau, txhuas, kub, tooj liab, nyiaj. Yog li nws tuaj yeem xaus lus tias tus nqi resistivity ntawm ib yam khoom qhia txog kev ntsuas ntawm lub peev xwm ntawm yam khoom los cuam tshuam hluav taws xob tam sim no.
Ib tug neeg coj zoo uas ua raws li Ohm txoj cai, ntawm qee qhov kub, nws tus nqi resistivity yog ywj pheej ntawm lub tshav fais fab, txhais tau tias yog tias qhov loj ntawm lub tshav fais fab hloov pauv, tus nqi resistivity tsis hloov pauv. Ntawm qhov tod tes, ib tug neeg coj uas tsis ua raws li Ohm txoj cai, nws tus nqi resistivity nyob ntawm lub tshav fais fab, txhais tau tias yog tias qhov loj ntawm lub tshav fais fab hloov pauv, tus nqi resistivity kuj hloov pauv.
Qhov resistivity ntawm tus hlau conductor nyob ntawm qhov kub thiab txias. Thaum qhov kub nce, qhov resistivity nce; conversely, thaum qhov kub txo qis, qhov resistivity txo qis. Thaum qhov kub nce, cov atoms txav mus sai dua thiab ua rau muaj kev tsis sib haum xeeb ntau dua, cuam tshuam kev txav mus los ntawm cov electrons, qeeb lawv cov dej ntws. Thaum qhov kub txo qis, cov atoms txav qeeb dua thiab ua kom muaj kev teeb tsa ntau dua, ua rau cov electron ntws du dua.
Qhov rov qab ntawm resistivity yog conductivity. Mathematically, kev sib raug zoo ntawm resistivity thiab conductivity yog qhia los ntawm equation:
σ = 1/ρ
Kev piav qhia: σ = tus neeg coj hluav taws xob conductivity, ρ = tus neeg coj hluav taws xob resistivity.
Lub chav ntawm resistivity yog Ωm yog li lub chav ntawm conductivity yog 1 / Ωm = (Ωm)-1
Cov nqi conductivity siab tshaj plaws yog muaj los ntawm cov neeg ua hluav taws xob lossis cov neeg ua hluav taws xob zoo thaum cov nqi conductivity qis tshaj plaws yog muaj los ntawm cov insulators hluav taws xob lossis cov neeg ua hluav taws xob tsis zoo. Tus neeg ua hluav taws xob zoo dua, nws qhov conductivity ntau dua. Qhov kev txiav txim ntawm cov hlau conductors nrog qhov siab tshaj plaws mus rau qis tshaj conductivity yog nyiaj, tooj liab, kub, txhuas, hlau, tin. Yog li nws tuaj yeem xaus lus tias tus nqi conductivity ntawm ib yam khoom qhia txog kev ntsuas ntawm lub peev xwm ntawm yam khoom los ua hluav taws xob tam sim no. Nyiaj muaj conductivity siab tab sis kim heev yog li tooj liab yog siv dav dua ua tus neeg ua hluav taws xob tam sim no.
