Incazelo yomthetho ka-Ohm
Cishe kuzo zonke iziqhubi zensimbi, insimu kagesi ilingana nobuningi bomsinga kagesi, lapho isilinganiso sensimu kagesi nobuningi bomsinga kagesi sihlala njalo. Kuvezwa ngokwezibalo nge-equation:
ρ = E / J
E = insimu kagesi , ρ = ukumelana , J = ukuminyana kwamanje
I-ρ engaguquki ibizwa ngokuthi i-resistivity, enenani elingaguquki futhi ayixhomekile ensimini kagesi ebangela ugesi.
Uma insimu kagesi ikhula, ubuningi bamandla kagesi nabo buyanda, kanti uma insimu kagesi incipha, ubuningi bamandla kagesi nabo buyancipha,
ukuze isilinganiso sensimu kagesi nobuningi bombane kagesi singaguquguquki. Lesi yisitatimende sezomthetho sika-Ohm. Ngakho-ke, isibalo esingenhla sichaza umthetho ka-Ohm kuphela uma u-ρ engaguquguquki futhi ungaxhomeki ensimini kagesi. Umthetho ka-Ohm awusebenzi uma inani lika-ρ lishintsha lapho insimu kagesi ishintsha.
Kodwa-ke, kulula ukukala amandla kagesi (V) kunensimu kagesi (E), ngakho-ke kulula futhi ukukala ugesi (I) kunobuningi bogesi kagesi (J). Ngakho-ke, ngaphezu kokushiwo ensimini kagesi, ubuningi bogesi kagesi kanye nokumelana (ρ), umthetho ka-Ohm uphinde uvezwe ngamandla kagesi, ugesi kagesi kanye nokumelana kagesi (R).
Okokuqala buyekeza umqhubi wentambo onobude (l), indawo enqamulayo (A) futhi kukhona umehluko wamandla kagesi (V) phakathi kwezinhlangothi ezimbili zentambo. Uma insimu kagesi efanayo ifana, khona-ke ubudlelwano phakathi kwensimu kagesi nomehluko wamandla kagesi buvezwa ku-equation V = E s (lesi sibalo sixoxiwe kumandla kagesi). Uma ubuningi bamandla kagesi afanayo bufana,
bese ubudlelwano phakathi kwamandla kagesi kanye nobuningi bamandla kagesi buvezwa ku-equation I = JA (le equation ixoxwe ngayo esihlokweni samandla kagesi).
Ukuze uthole isibalo esichaza ubudlelwano phakathi kwamandla kagesi (V), amandla kagesi (I) kanye nokumelana kagesi (R),
faka u-E no-J esikhundleni se-equation of resistivity, u-E esikhundleni se-equation of electric potential kanye no-J esikhundleni se-equation of electric current:
Lesi yisibalo esichaza ubudlelwano phakathi kwamandla kagesi (V), amandla kagesi (I) kanye nokumelana kagesi (R) kumqhubi. Ngokusekelwe kulesi sibalo, kungashiwo ukuthi ukumelana kagesi kumqhubi kuwukuqhathanisa umehluko wamandla kagesi namandla kagesi kumqhubi.
Umthetho we-Ohm uthi isilinganiso phakathi komehluko wamandla kagesi kugesi kagesi asiguquki. Ngamanye amazwi, lesi sibalo sichaza umthetho we-Ohm kuphela uma ukumelana kagesi (R) kungaguquki. Umthetho we-Ohm awusebenzi uma ukumelana kagesi kungaguquki.
Ku-equation engenhla, ukumelana kukagesi (R) ku-conductor nakho kunobudlelwano ne-resistivity (ρ), ubude bomqhubi (l) kanye nendawo enqamulayo (A) yomqhubi. Kuvezwe ngokwezibalo ku-equation:
Isilinganiso somthetho ka-Ohm
Umthetho ka-Ohm uchazwa ngama-equation amabili, okungukuthi u-ρ = E/J no-R = V/I. Kufanele kukhunjulwe ukuthi la ma-equation amabili ayi-equation yomthetho ka-Ohm kuphela uma u-ρ engaguquki kanti u-R engaguquki. Uma u-ρ no-R bomqhubi beshintsha, la ma-equation amabili awachazi umthetho ka-Ohm, kodwa u-ρ = E/J uchaza ukumelana kohlobo lomqhubi kanye no-R = V/I uchaza ukumelana kukagesi komqhubi.
Isibalo ρ = E/J singabhalwa njengo-E = ρ J. Uma u-ρ engaguquguquki, u-E ulingana no-J, okusho ukuthi uma u-E enyuka u-J uyanda noma uma u-E ehla u-J uyancipha.
Ngokufanayo, isibalo u-R = V/I singabhalwa njengo-V = I R. Uma u-R engaguquguquki khona-ke u-V ulingana ngqo no-I, okusho ukuthi uma u-V enyuka, khona-ke ngiyanda noma uma u-V ehla, khona-ke ngiyancipha.
Izinto ezilalela umthetho we-Ohm kuthiwa ziyi-ohmic, kanti izinto ezingalaleli umthetho we-Ohm kuthiwa ziyi-nonohmic. Cishe bonke abaqhubi bensimbi bangama-ohmic, kanti ezinye izinto eziningi aziyi-nonohmic.
Ezintweni ezingezona ezikagesi, ukumelana kukagesi akuhlali njalo futhi kuncike kumandla kagesi kanye nomehluko wamandla kagesi. Lokhu kusho ukuthi uma amandla kagesi eshintsha khona-ke ukumelana kukagesi kwezinto nakho kuyashintsha, kanye nokuthi uma amandla kagesi eshintsha khona-ke ukumelana kukagesi kwezinto nakho kuyashintsha. Ngenxa yokumelana kukagesi kuyashintsha kunendaba engeyona eyokagesi, amandla kagesi (V) awalingani ngqo namandla kagesi (I).
Igrafu V, I kanye no-R
Ku-ohmic matter, isilinganiso u-V kuya ku-I sihlala njalo, esimelelwa umugqa oqondile. Isibonelo sezinto ze-ohmic yi-conductor yensimbi. Okwamanje ku-nonohmic matter, isilinganiso sika-V kuya ku-I asihlali njalo, esimelelwa umugqa ogobile. Izibonelo zezinto ze-nonohmic yi-semiconductor diodes kanye nama-transistors.
Umthetho ka-Ohm usebenza kuphela ezintweni ze-ohmic futhi awusebenzi kuzo zonke izinto, ngakho-ke akufaneleki ukusho imithetho efana nomthetho kaNewton noma eminye imithetho yemvelo. Umthetho wemvelo empeleni usebenza kuzo zonke izinto, hhayi ezintweni ezithile kuphela. Kodwa ukukhulunywa ngomthetho ka-Ohm sekuyinto evamile, ngakho-ke kusabizwa ngokuthi umthetho ka-Ohm, uma nje kukhunjulwa ukuthi umthetho ka-Ohm usebenza kuphela ezintweni ze-ohmic.
