ʻAtikala e pili ana i ka Resistivity
E pili ana i ke au uila, ua kūkākūkā ʻia ka nui o ke au uila, no laila ua wehewehe ʻia ke kahua uila ma ke kumuhana e pili ana i ke kahua uila. Aia ke kahua uila a me ke au uila i loko o kahi alakaʻi inā he ʻokoʻa hiki i ke alakaʻi, ʻoiai inā ʻaʻohe ʻokoʻa hiki, a laila ʻaʻohe kahua uila a me ke au uila.
Ma aneane nā alakaʻi metala āpau, ua kūlike pololei ke kahua uila me ka nui o ke au uila, kahi e mau ai ka lakio o ke kahua uila i ka nui o ke au uila. ʻO ka waiwai o ka hoʻohālikelike ʻana o ke kahua uila i ka nui o ke au ua kapa ʻia ʻo resistivity. Ma ke ʻano makemakika, ua ʻōlelo ʻia ka pilina ma waena o ke kahua uila, ka nui o ke au, a me ka resistivity ma ka hoohalike:
ρ = E / J
ρ = resistivity, E = kahua uila , J = density au
ʻO kekahi o nā haʻilula kahua uila ʻo E = V/d kahi ʻo V = ka ʻokoʻa hiki uila = ka uila uila a me d = ka mamao i hiki ai i ke anakahi kahua uila ke Volt/mika (V/m). ʻO ke haʻilula o ka nui o kēia manawa ʻo J = I/A kahi ʻo I = ke au uila a me 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 kaulike o ka resistivity ʻo ρ = E/J i hiki ai i ke anakahi resistivity ke V/m: A/m2 = V/mxm2 / A = V/A (m) = Ω m (heluhelu: Ohmmeter). ʻO Ω = Volt / Ampere kahi anakahi o ke kū'ē uila.
ʻO ka waiwai resistivity nui loa nona nā mea hoʻokaʻawale uila a i ʻole, ʻoiai ʻo ka resistivity liʻiliʻi loa nona kahi alakaʻi uila maikaʻi. ʻO ka maikaʻi o ka lawe ʻana o kahi alakaʻi i kahi au uila, ʻo ka liʻiliʻi o ke kū'ē o ke ʻano o ke alakaʻi. ʻO ke kauoha o nā alakaʻi metala nona ka resistivity nui loa a liʻiliʻi loa he tin, kila, alumini, gula, keleawe, kālā. No laila, hiki ke hoʻoholo ʻia ʻo ka waiwai kū'ē o kahi mea e hōʻike ana i kahi ana o ka hiki o ka mea ke kāohi i kahi au uila.
ʻO kahi alakaʻi uila maikaʻi a me ka mālama ʻana i ke kānāwai o Ohm, ma kahi mahana, ʻaʻole hilinaʻi ka waiwai resistivity i ke kahua uila, ʻo ia hoʻi inā loli ke kahua uila ʻaʻole e loli ka waiwai o ka resistivity. I ka ʻaoʻao ʻē aʻe, no nā alakaʻi uila i kūlike ʻole me ke kānāwai o Ohm, hilinaʻi ka waiwai resistivity i ke kahua uila, ʻo ia hoʻi inā loli ka nui o ke kahua uila a laila loli pū ka waiwai R.
Aia ke kū'ē'ē o ke alaka'i metala i ka mahana. Inā pi'i ka mahana o ka metala, pi'i ka kū'ē'ē o ka metala, akā inā emi ka mahana o ka metala, emi ka kū'ē'ē o ka metala. I ka pi'i'ana o ka mahana, ne'e wikiwiki nā'ātoma a ho'onohonoho pono'ī'ia i mea e ālai ai lākou i ka ne'e'ana o nā electrons, e lohi ai ke kahe'ana o nā electrons. Ke emi ka mahana, ne'e mālie nā'ātoma a ho'onohonoho pono'ī'ia i mea e ma'alahi ai ke kahe'ana o ka electrons.
ʻO ke kū'ē o ka resistivity ʻo ia ka conductivity. Ma ke ʻano makemakika, ua ʻōlelo ʻia ka pilina ma waena o ka resistivity a me ka conductivity ma o ka hoohalike:
σ = 1/ ρ
σ = conductivity o ke alakaʻi, ρ = resistivity.
ʻO ke anakahi o ka resistivity ʻo Ωm i hiki ai i ke anakahi o ka conductivity he 1 / Ωm = (Ωm) -1
ʻO ka waiwai conductivity nui loa nona ka mea alakaʻi uila, ʻoiai ʻo ka waiwai conductivity liʻiliʻi loa nona ka mea hoʻokaʻawale uila a i ʻole ka mea alakaʻi uila maikaʻi ʻole. ʻO ka maikaʻi o ka mea alakaʻi e hāʻawi i kahi au uila, ʻoi aku ka nui o ka conductivity o ke alakaʻi. ʻO ke kauoha o nā mea alakaʻi metala nona ka conductivity nui loa i ka mea liʻiliʻi loa he kālā, keleawe, gula, alumini, kila, tin. No laila, hiki ke hoʻoholo ʻia ʻo ka waiwai o ka conductivity o kahi mea e hōʻike ana i ke ana o ka hiki o ka mea ke lawe i kahi au uila. He nui ka conductivity o ke kālā akā he pipiʻi ia no laila ua hoʻohana nui ʻia ke keleawe ma ke ʻano he alakaʻi uila.
