Tsab xov xwm hais txog Resistivity
Hais txog qhov hluav taws xob tam sim no, qhov ceev ntawm qhov hluav taws xob tam sim no tau tham txog lawm, yog li ntawd kuj tau piav qhia txog lub zog hluav taws xob hauv lub ncauj lus txog lub zog hluav taws xob. Lub zog hluav taws xob thiab lub zog hluav taws xob nyob hauv tus neeg coj hluav taws xob yog tias muaj qhov sib txawv ntawm lub zog hauv tus neeg coj hluav taws xob, thaum yog tias tsis muaj qhov sib txawv ntawm lub zog, ces kuj tsis muaj lub zog hluav taws xob thiab lub zog hluav taws xob.
Hauv yuav luag txhua tus hlau conductors, lub teb hluav taws xob yog ncaj qha proportional rau qhov ceev ntawm lub hluav taws xob tam sim no, qhov twg qhov piv ntawm lub teb hluav taws xob rau qhov ceev ntawm lub hluav taws xob tam sim no yog tas li. Tus nqi ntawm kev sib piv ntawm lub teb hluav taws xob rau qhov ceev tam sim no hu ua resistivity. Mathematically, kev sib raug zoo ntawm lub teb hluav taws xob, qhov ceev tam sim no, thiab resistivity yog hais nyob rau hauv equation:
ρ = E / J
ρ = resistivity, E = hluav taws xob teb , J = tam sim no ceev
Ib qho ntawm cov qauv hluav taws xob yog E = V/d qhov twg V = qhov sib txawv ntawm lub zog hluav taws xob = hluav taws xob voltage thiab d = nrug yog li ntawd lub tshuab hluav taws xob yog Volt/meter (V/m). Cov qauv ntawm qhov 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 lub chav ntawm qhov ceev tam sim no yog Ampere/meter squared (A/m2 ) . Cov qauv ntawm qhov tsis kam yog ρ = E/J yog li ntawd lub tshuab tsis kam yog V/m: A/m2 = V/mxm2 / A = V/A (m) = Ω m (nyeem: Ohmmeter). Ω = Volt / Ampere yog ib chav ntawm kev tiv thaiv hluav taws xob.
Tus nqi resistivity loj tshaj plaws yog cov insulators hluav taws xob lossis, thaum qhov resistivity me tshaj plaws yog tus neeg coj hluav taws xob zoo. Tus neeg coj hluav taws xob zoo dua xa hluav taws xob tam sim no, qhov tsis kam ntawm hom neeg coj hluav taws xob me dua. Qhov kev txiav txim ntawm cov hlau conductors uas muaj qhov loj tshaj plaws mus rau qhov tsis kam me tshaj plaws yog tin, hlau, txhuas, kub, tooj liab, nyiaj. Yog li, nws tuaj yeem xaus lus tias tus nqi tsis kam ntawm ib yam khoom hais txog kev ntsuas ntawm lub peev xwm ntawm yam khoom los tiv thaiv hluav taws xob tam sim no.
Ib tug neeg coj zoo thiab ua raws li Ohm txoj cai, ntawm qee qhov kub, tus nqi resistivity tsis nyob ntawm lub teb hluav taws xob, txhais tau tias yog tias lub teb hluav taws xob hloov pauv tus nqi ntawm resistivity tsis hloov pauv. Ntawm qhov tod tes, rau cov neeg coj uas tsis ua raws li Ohm txoj cai, tus nqi resistivity nyob ntawm lub teb hluav taws xob, txhais tau tias yog tias qhov loj ntawm lub teb hluav taws xob hloov pauv ces R-tus nqi kuj hloov pauv.
Qhov resistivity ntawm tus hlau conductor nyob ntawm qhov kub thiab txias. Yog tias qhov kub ntawm hlau nce, qhov resistivity ntawm hlau nce, thaum yog tias qhov kub ntawm hlau txo qis, qhov resistivity ntawm hlau txo qis. Thaum qhov kub nce, cov atoms txav mus sai dua thiab tau teeb tsa tsis tu ncua kom lawv thaiv kev txav mus los ntawm cov electrons, ua rau cov electrons ntws qeeb dua. Thaum qhov kub txo qis, cov atoms txav qeeb qeeb thiab tau teeb tsa tsis tu ncua kom cov electrons ntws du dua.
Qhov txawv ntawm resistivity yog conductivity. Mathematically, kev sib raug zoo ntawm resistivity thiab conductivity yog hais los ntawm equation:
σ = 1/ ρ
σ = conductivity ntawm tus neeg xyuas pib, ρ = resistivity.
Lub chav ntawm resistivity yog Ωm yog li ntawd lub chav ntawm conductivity yog 1 / Ωm = (Ωm) -1
Tus nqi conductivity loj tshaj plaws yog tus tswv ntawm tus neeg hluav taws xob, thaum tus nqi conductivity me tshaj plaws yog tus insulator hluav taws xob lossis tus neeg hluav taws xob tsis zoo. Tus neeg hluav taws xob zoo dua xa hluav taws xob, tus neeg hluav taws xob conductivity ntau dua. Cov hlau conductivity loj tshaj plaws mus rau me tshaj plaws yog nyiaj, tooj liab, kub, txhuas, hlau, tin. Yog li, nws tuaj yeem xaus lus tias tus nqi ntawm conductivity ntawm ib yam khoom qhia txog kev ntsuas ntawm lub peev xwm ntawm yam khoom los nqa hluav taws xob. Nyiaj muaj conductivity loj tab sis kim heev yog li tooj liab siv dav dua ua tus neeg hluav taws xob.
