Isihloko samandla kagesi sixoxe ngobuningi bamandla kagesi, kanti insimu kagesi nayo ichazwe esihlokweni samandla kagesi. Insimu kagesi kanye namandla kagesi kukhona kumqhubi lapho kunomehluko ongaba khona kumqhubi; ngokuphambene nalokho, uma kungekho mehluko ongaba khona, insimu kagesi noma amandla kagesi akhona.
Kumqhubi wensimbi, insimu kagesi ilingana ngqo nobuningi bamanje, lapho isilinganiso sensimu kagesi nobuningi bamanje singu-constant. Isilinganiso sensimu kagesi nobuningi bamanje sibizwa ngokuthi i-resistivity noma i-specific resistance . Ngokwezibalo, ubudlelwano phakathi kwensimu kagesi, ubukhulu bamanje, kanye nokumelana okuthile kuvezwa kulesi sibalo:
Incazelo: ρ = ukumelana okuthile, E = insimu kagesi, J = ukuminyana kwamanje
Enye yamafomula ensimu kagesi yi-E = V/s lapho i-V = umehluko wamandla kagesi = i-voltage kagesi kanye ne-s = ibanga, ngakho iyunithi yensimu kagesi yi-Volt/meter (V/m). Ifomula yobuningi bamanje yi-J = I/A lapho i-I = ugesi wamanje kanye ne-A = indawo enqamulayo yomqhubi, ngakho iyunithi yobuningi bamanje yi-Ampere/meter squared (A/m 2 ). Ifomula yokumelana yi-ρ = E/J ngakho iyunithi yokumelana yi-V/m: A/m 2 = V/mxm 2 /A = V/A (m) = Ω m (funda: i-Ohm meter). I-Ω = Volt/Ampere iyiyunithi yokumelana kagesi, maqondana nale yunithi kuchazwa esihlokweni mayelana nomthetho we-Ohm.
Amanani okumelana aphezulu kakhulu anama-insulator kagesi noma ama-conductor kagesi ampofu, kuyilapho amanani okumelana aphansi kakhulu anama-conductor kagesi noma ama-conductor kagesi amahle. Uma umqhubi eqhuba kahle ugesi, kulapho ukumelana kwawo kwehla khona. Uhlelo lwabaqhubi bensimbi abanokumelana okuphezulu kuya kokuphansi yi-tin, insimbi, i-aluminium, igolide, ithusi, isiliva. Ngakho-ke kungaphethwa ngokuthi inani lokumelana lento libonisa isilinganiso sekhono lento lokuvimbela ugesi.
Umqhubi omuhle olalela umthetho ka-Ohm, ezingeni lokushisa elithile, inani lakhe lokumelana alincikile ensimini kagesi, okusho ukuthi uma ubukhulu bensimu kagesi bushintsha, inani lokumelana alishintshi. Ngokuphambene nalokho, umqhubi ongalaleli umthetho ka-Ohm, inani lakhe lokumelana lincike ensimini kagesi, okusho ukuthi uma ubukhulu bensimu kagesi bushintsha, inani lokumelana nalo liyashintsha.
Ukumelana komqhubi wensimbi kuncike ekushiseni. Njengoba izinga lokushisa likhuphuka, ukumelana kuyanda; ngokuphambene nalokho, njengoba izinga lokushisa liyancipha, ukumelana kuyancipha. Njengoba izinga lokushisa likhuphuka, ama-athomu ahamba ngokushesha futhi aba nokuphazamiseka okukhulu, okuvimbela ukunyakaza kwama-electron, okunciphisa ukuhamba kwawo. Njengoba izinga lokushisa lehla, ama-athomu ahamba kancane futhi ahleleke kakhulu, okuvumela ukugeleza kwama-electron kube bushelelezi.
I-inverse ye-resistivity yi-conductivity. Ngokwezibalo, ubudlelwano phakathi kwe-resistivity kanye ne-conductivity buvezwa yi-equation:
σ = 1/ρ
Incazelo: σ = umqhubi wokuqhuba, ρ = ukumelana nomqhubi wokuqhuba.
Iyunithi yokumelana yi-Ωm ngakho iyunithi yokuqhuba ingu-1/Ωm = (Ωm)-1
Amanani okuqhuba okuphezulu kakhulu aphethwe ngabaqondisi bakagesi noma abaqondisi bakagesi abahle kanti amanani okuqhuba aphansi kakhulu aphethwe ngabavikeli bakagesi noma abaqondisi bakagesi ababi. Uma umqhubi eqhuba kangcono ugesi, kulapho ugesi wakhe uqhubeka khona. Ukuhleleka kwabaqhubi bensimbi abanokuqhuba okuphezulu kuya kokuphansi kakhulu yisiliva, ithusi, igolide, i-aluminium, insimbi, ithini. Ngakho-ke kungaphethwa ngokuthi inani lokuqhuba lento libonisa isilinganiso sekhono lento lokuqhuba ugesi. Isiliva linokuqhuba okuphezulu kodwa liyabiza ngakho ithusi lisetshenziswa kabanzi njengomqhubi wamandla kagesi.
