Ke hoʻomaopopo nei i ke kānāwai o Ohm
E aʻo pū i nā mea Nā nīnau hoʻohālike no ke kānāwai o Ohm a hiki Kūkākūkā o ke kānāwai o Ohm
Ma aneane nā alakaʻi metala āpau, kahua uila kūlike i ka nui o ke au uila, kahi e mau ai ka lakio o ke kahua uila i ka nui o ke au uila. Hōʻike ʻia ma ka makemakika ma o ka hoohalike:
ρ = E / J
Wehewehe: E = kahua uila, ρ = resistivity, J = ka nui o ke au uila.
Ua kapa ʻia ke kūpaʻa o ka proportionality ρ ʻano o ke kū'ē a i ʻole ke kū'ē ʻana nona ka waiwai paʻa a ʻaʻole hilinaʻi i ke kahua uila e hoʻopuka ana i ke au uila.
Inā piʻi ke kahua uila, piʻi pū ka nui o ke au uila, i ka ʻaoʻao ʻē aʻe, inā emi ke kahua uila, emi pū ka nui o ke au uila, no laila e mau ana ka lakio o ke kahua uila i ka nui o ke au uila. He ʻōlelo kēia. Ke kānāwai o Ohm. No laila, wehewehe ka hoohalike ma luna i ke kānāwai o Ohm ke kūpaʻa ʻo ρ a kūʻokoʻa hoʻi i ke kahua uila. ʻAʻole pili ke kānāwai o Ohm inā loli ka waiwai o ρ ke loli ke kahua uila.
Eia nō naʻe, ʻoi aku ka maʻalahi o ke ana ʻana i ka hiki ke uila (V) ma mua o ke kahua uila (E), a ʻoi aku ka maʻalahi o ke ana ʻana i ke au uila (I) ma mua o ka nui o ke au uila (J). No laila, me ka hōʻike ʻia ʻana ma kahua uila, ka nui o ke au uila a hiki ʻano o ke kū'ē (ρ), ua hōʻike ʻia ke kānāwai o Ohm ma hiki ke uila, au uila a hiki ke kū'ē uila (R).
ʻO ka mea mua, e noʻonoʻo i kahi alakaʻi uea nona ka lōʻihi (l), kahi ʻāpana ʻāpana (A) a me kahi ʻokoʻa hiki uila (V) ma waena o nā wēlau ʻelua o ke uea. Inā like ke kahua uila, a like paha ma loko, a laila ua hōʻike ʻia ka pilina ma waena o ke kahua uila a me ka ʻokoʻa hiki uila ma ka hoohalike V = E s (Ua kūkākūkā ʻia kēia kaulike ma ka mea hiki ke uila). Inā like ka nui o ke au uila, ʻo ia hoʻi, ua like mau ia, a laila ua hōʻike ʻia ka pilina ma waena o ka nui o ke au uila a me ke au uila ma ka hoohalike I = JA (Ua kūkākūkā ʻia kēia kaulike ma ka mea au uila).
No ka loaʻa ʻana o kahi hoohalike e hōʻike ana i ka pilina ma waena hiki ke uila (V), au uila (ʻO wau) a me ke kū'ē uila (R), e pani iā E a me J ma ke kaulike kū'ē me E ma ke kaulike hiki uila a me J ma ke kaulike au uila:
He hoohalike kēia e wehewehe ana i ka pilina ma waena o ka hiki uila (V), ke au uila (I) a me ke kū'ē uila (R) i loko o kahi alakaʻi. Ma muli o kēia hoohalike, hiki ke ʻōlelo ʻia ʻo ke kū'ē uila i loko o kahi alakaʻi ka lakio o ka ʻokoʻa hiki uila i ke au uila i loko o ke alakaʻi.
ʻŌlelo ke kānāwai o Ohm he mau ka lakio o ka ʻokoʻa o ka hiki ke uila i ke au uila. I nā huaʻōlelo ʻē aʻe, wehewehe kēia kaulike i ke kānāwai o Ohm ke mau ka pale uila (R). ʻAʻole pili ke kānāwai o Ohm inā ʻaʻole mau ka pale uila, ʻo ia hoʻi, loli ia.
Ma ka hoʻopuka ʻana o ka hoohalike ma luna, pili pū ke kū'ē uila (R) o kahi alakaʻi i ke kū'ē kiko'ī (ρ), ka lōʻihi o ke alakaʻi (l) a me ka ʻāpana ʻāpana (A) o ke alakaʻi. Ma ke ʻano makemakika, ua hōʻike ʻia kēia ma ka hoohalike:
Ua kūkākūkā ʻia kēia kaulike ma ke kikoʻī ma ka ʻatikala ma ke kū'ē uila.
Ke Kumukānāwai o Ohm
Ua wehewehe ʻia ke kānāwai o Ohm e ʻelua mau kaulike, ʻo ia hoʻi ʻo ρ = E/J a me R = V/I. Pono e hoʻomaopopo ʻia ʻo kēia mau kaulike ʻelua he mau kaulike kānāwai o Ohm wale nō ke kūpaʻa ʻo ρ a kūpaʻa ʻo R. Inā loli ʻo ρ a me R o kahi alakaʻi, a laila ʻaʻole wehewehe kēia mau kaulike ʻelua i ke kānāwai o Ohm, akā wehewehe ʻo ρ = E/J. ʻano o ke kū'ē he alakaʻi a wehewehe ʻo R = V/I ke kū'ē uila he alakaʻi.
Hiki ke kākau ʻia ke kaulike ρ = E/J penei E = ρ J. Ke paʻa ʻo ρ a laila kūlike pololei ʻo E me J, ʻo ia hoʻi inā piʻi ʻo E a laila piʻi ʻo J a inā emi ʻo E a laila emi ʻo J.
Pēlā nō, hiki ke kākau ʻia ke kaulike R = V/I penei: V = I R. Ke paʻa ʻo R, kūlike pololei ʻo V me I, ʻo ia hoʻi, inā piʻi ʻo V, piʻi ʻo I, a inā emi ʻo V, emi ʻo I.
ʻO nā mea e mālama ana i ke kānāwai o Ohm ua ʻōlelo ʻia he ohmic, ʻoiai ʻo nā mea i mālama ʻole i ke kānāwai o Ohm ua ʻōlelo ʻia he nonohmic. ʻO ka hapa nui o nā alakaʻi metala he ohmic, ʻoiai he nui nā mea ʻē aʻe he nonohmic.
I loko o nā mea ʻole-ohmic, ʻaʻole mau ke kūʻē uila, akā loli ma muli o ke au a me ka ʻokoʻa hiki. ʻO ke ʻano kēia inā loli ke au, loli pū ke kūʻē o ka mea, a pēlā nō, inā loli ke voltage, loli pū ke kūʻē o ka mea. No ka mea, loli ke kūʻē uila, i loko o nā mea ʻole-ohmic, ʻaʻole kūlike pololei ke voltage (V) me ke au (I).
Nā kiʻi V, I a me R
I loko o nā mea ohmic, ʻo ka lakio o V a i I he paʻa, i hōʻike ʻia e kahi laina pololei. ʻO nā hiʻohiʻona o nā mea ohmic he mau alakaʻi metala. I kēia manawa, i loko o nā mea nonohmic, ʻaʻole paʻa ka lakio o V a i I, i hōʻike ʻia e kahi laina piʻo. ʻO nā hiʻohiʻona o nā mea nonohmic he mau diode semiconductor a me nā transistors.
Pili wale ke kānāwai o Ohm i nā mea ohmic ʻaʻole i nā mea āpau, no laila he hewa ke kapa ʻana iā ia he kānāwai e like me nā kānāwai o Newton a i ʻole nā kānāwai ʻē aʻe o ka physics. Pili maoli nā kānāwai o ka physics i nā mea āpau, ʻaʻole wale i kekahi mau mea. Eia nō naʻe, ua lilo ka hoʻohana ʻana i ke kānāwai o Ohm i mea maʻamau, no laila ua kapa ʻia ʻo ia ke kānāwai o Ohm, inā e hoʻomanaʻo ʻia ʻo ke kānāwai o Ohm e pili wale i nā mea ohmic. Ma waho aʻe o ke kānāwai o Ohm, ʻo kekahi laʻana o kahi kuhihewa maʻamau ka hoʻohana ʻana i ke kānāwai kinoea kūpono a i ʻole ke kānāwai o Hooke.
