Hauv tsab xov xwm txog hluav taws xob tam sim no tau tham txog hauv lub rooj sib tham txog hluav taws xob, thiab lub zog hluav taws xob Nws tau piav qhia hauv tsab xov xwm txog cov teb hluav taws xob. Cov teb hluav taws xob thiab cov hluav taws xob tam sim no muaj nyob rau hauv tus neeg coj hluav taws xob yog tias muaj qhov sib txawv ntawm qhov muaj peev xwm ntawm tus neeg xyuas pib, ntawm qhov tod tes, yog tias tsis muaj qhov sib txawv ces tsis muaj hluav taws xob thiab hluav taws xob tam sim no.
Hauv ib lub hlau conductor, lub teb hluav taws xob yog proportional ncaj qha 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 los yog hom tsis kam. Kev suav lej, kev sib raug zoo ntawm lub zog hluav taws xob, qhov ceev tam sim no thiab kev tiv thaiv 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 mis kev tiv taus yog ρ = E/J yog li ntawd lub chav ntawm qhov tsis kam tshwj xeeb yog V/m: A/m2 = V/m x m2/A = V/A (m) = Ω m (nyeem: Ohm meter). Ω = Volt/Ampere yog ib chav ntsuas ntawm kev tiv thaiv hluav taws xob, chav no tau piav qhia hauv tsab xov xwm txog Txoj cai ntawm Ohm.
Qhab Nia kev tiv taus tus nqi loj tshaj plaws yog cov insulators hluav taws xob lossis cov neeg ua hluav taws xob tsis zoo, thaum tus nqi kev tiv taus Tus me tshaj plaws yog tus uas muaj tus neeg coj hluav taws xob zoo lossis tus neeg coj hluav taws xob. Tus neeg coj hluav taws xob zoo dua, tus me dua kev tiv taus tus neeg xyuas pib. Qhov kev txiav txim ntawm cov hlau hlau uas muaj kev tiv taus Txij qhov loj tshaj plaws mus rau qhov me tshaj plaws yog tin, hlau, txhuas, kub, tooj liab, nyiaj. Yog li ntawd, nws tuaj yeem xaus lus tias tus nqi kev tiv taus ib yam khoom hais txog qhov loj ntawm lub peev xwm ntawm yam khoom los tiv thaiv 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.
