Ua kūkākūkā ka ʻatikala e pili ana i ke au uila i ka nui o ke au uila, a ua wehewehe pū ʻia ke kahua uila ma ka ʻatikala e pili ana i nā kahua uila. Aia ke kahua uila a me ke au uila i loko o kahi alakaʻi inā he ʻokoʻa hiki ke hana ma waena o ke alakaʻi; i ka ʻaoʻao ʻē aʻe, inā ʻaʻohe ʻokoʻa hiki ke hana, ʻaʻohe kahua uila a ʻaʻole hoʻi he au uila.
I loko o kahi alakaʻi metala, ua kūlike pololei ke kahua uila me ka nui o ke au, kahi i kūlike ai ka lakio o ke kahua uila i ka nui o ke au. Ua kapa ʻia ka lakio o ke kahua uila i ka nui o ke au he resistivity a i ʻole ke kū'ē kikoʻī . Ma ke ʻano makemakika, ua hōʻike ʻia ka pilina ma waena o ke kahua uila, ka nui o ke au, a me ke kū'ē kikoʻī ma ka hoohalike:
Wehewehe: ρ = ke kū'ē kiko'ī, E = kahua uila, J = ka nui o ke au
ʻO kekahi o nā haʻilula kahua uila ʻo E = V/s kahi ʻo V = ka ʻokoʻa hiki uila = ka uila uila a ʻo s = ka mamao, no laila ʻo ke anakahi o ke kahua uila ʻo Volt/mika (V/m). ʻO ke ʻano o ka nui o kēia manawa ʻo J = I/A kahi ʻo I = ke au uila a ʻo A = ka ʻāpana ʻāpana o ke alakaʻi, no laila ʻo ke anakahi o ka nui o kēia manawa ʻo Ampere/mika huinahā (A/m2 ) . ʻO ke ʻano o ka resistivity ʻo ρ = E/J no laila ʻo ke anakahi o ke kūʻē ʻana ʻo V/m: A/m2 = V/mxm2 / A = V/A (m) = Ω m (heluhelu: Ohm mika). ʻO Ω = Volt/Ampere kahi anakahi o ke kūʻē uila, e pili ana i kēia anakahi ua wehewehe ʻia ma ka ʻatikala e pili ana i ke kānāwai o Ohm.
ʻO nā waiwai resistivity kiʻekiʻe loa i loaʻa i nā mea hoʻokaʻawale uila a i ʻole nā alakaʻi uila maikaʻi ʻole, ʻoiai ʻo nā waiwai resistivity haʻahaʻa loa i loaʻa i nā alakaʻi uila a i ʻole nā alakaʻi uila maikaʻi. ʻO ka maikaʻi o ka alakaʻi e alakaʻi i ke au uila, ʻo ka haʻahaʻa o kona resistivity . ʻO ke kaʻina o nā alakaʻi metala me ka resistivity kiʻekiʻe a haʻahaʻa loa he tin, kila, alumini, gula, keleawe, kālā. No laila hiki ke hoʻoholo ʻia ʻo ka waiwai resistivity o kahi mea e hōʻike ana i kahi ana o ka hiki o ka mea ke pale i ke au uila.
ʻO kahi alakaʻi maikaʻi e mālama ana i ke kānāwai o Ohm, ma kahi mahana, kūʻokoʻa kona waiwai resistivity mai ke kahua uila, ʻo ia hoʻi inā loli ka nui o ke kahua uila, ʻaʻole e loli ka waiwai resistivity. I ka ʻaoʻao ʻē aʻe, ʻo kahi alakaʻi i hoʻolohe ʻole i ke kānāwai o Ohm, pili kona waiwai resistivity i ke kahua uila, ʻo ia hoʻi inā loli ka nui o ke kahua uila, e loli pū ka waiwai resistivity.
Aia ke kū'ē'ē o kahi alaka'i metala i ka mahana. Ke pi'i a'e ka mahana, pi'i a'e ka kū'ē'ē; ma ke 'ano 'ē a'e, ke emi nei ka mahana, emi iho ka kū'ē'ē. Ke pi'i a'e ka mahana, ne'e wikiwiki nā 'ātoma a lilo i mea ho'ohaunaele, e pale ana i ka ne'e 'ana o nā electrons, e ho'olohi ana i ko lākou kahe 'ana. Ke emi nei ka mahana, ne'e mālie nā 'ātoma a lilo i mea ho'onohonoho pono, e 'ae ana i ke kahe 'ana o ka electrons me ka ma'alahi.
ʻO ke ʻano ʻē o ka resistivity ʻo ia ka conductivity. Ma ke ʻano makemakika, ua hōʻike ʻia ka pilina ma waena o ka resistivity a me ka conductivity e ka hoohalike:
σ = 1/ρ
Wehewehena: σ = conductivity o ke alakaʻi, ρ = resistivity o ke alakaʻi.
ʻO ke anakahi o ka resistivity ʻo Ωm no laila ʻo ke anakahi o ka conductivity he 1/Ωm = (Ωm)-1
ʻO nā waiwai conductivity kiʻekiʻe loa i loaʻa i nā alakaʻi uila a i ʻole nā alakaʻi uila maikaʻi ʻoiai ʻo nā waiwai conductivity haʻahaʻa loa i loaʻa i nā insulators uila a i ʻole nā alakaʻi uila maikaʻi ʻole. ʻO ka maikaʻi o ka alakaʻi e alakaʻi i ke au uila, ʻoi aku ka nui o kona conductivity. ʻO ke kaʻina o nā alakaʻi metala me ka conductivity kiʻekiʻe a haʻahaʻa loa he kālā, keleawe, gula, alumini, kila, tin. No laila hiki ke hoʻoholo ʻia ʻo ka waiwai conductivity o kahi mea e hōʻike ana i kahi ana o ka hiki o ka mea ke alakaʻi i ke au uila. He kiʻekiʻe ka conductivity o ke kālā akā he pipiʻi no laila hoʻohana nui ʻia ke keleawe ma ke ʻano he alakaʻi o ke au uila.
