Te Mārama ki te Ture a Ohm
Akohia hoki ngā rauemi mō ngā tauira pātai ture a Ohm me te matapaki i ngā pātai ture a Ohm.
I roto i te nuinga o ngā ara iahiko whakarewa, mara hiko ōrite ki te matotoru o te iahiko hiko, ina he pumau te ōwehenga o te papa hiko ki te kiato o te iahiko hiko. Ka whakaaturia mā te pāngarau mā te whārite:
ρ = E / J
Whakaahuatanga: E = papa hiko, ρ = ātete, J = kiato iahiko.
Ko te pūmau ōwehenga ρ e kiia ana ko te ātete motuhake , ko te ātete rānei, he pūmau tōna uara, ā, kāore e whakawhirinaki ki te papa hiko e whakaputa ana i te iahiko.
Ki te piki ake te papa hiko, ka piki ake anō hoki te kiato o te iahiko hiko. I tetahi atu taha, ki te heke te papa hiko, ka heke anō hoki te kiato o te iahiko hiko, kia pumau tonu ai te ōwehenga o te papa hiko ki te kiato o te iahiko hiko. He kōrero tēnei mō te ture a Ohm . Nō reira, ka whakamāramahia e te whārite i runga ake nei te ture a Ohm ina pumau noa a ρ, ā, kāore e pā ki te papa hiko. Kāore te ture a Ohm e pā ana ki te rerekētanga o te uara o ρ ina rerekē te papa hiko.
Heoi, he māmā ake te ine i te pūmanawa hiko (V) i te mara hiko (E), ā, he māmā ake hoki te ine i te iahiko (I) i te kiato iahiko (J). Nō reira, i tua atu i te whakapuakitanga i roto i ngā kupu o te mara hiko , te kiato iahiko me te ātete (ρ), ka whakapuakina anō hoki te ture a Ohm i roto i ngā kupu o te pūmanawa hiko , te iahiko me te ātete hiko (R).
Tuatahi, whakaarohia he ara iahiko he roa (l), he horahanga whakawhiti-wāhanga (A) ā, he rerekētanga pūmanawa hiko (V) kei waenganui i ngā pito e rua o te waea. Mena he ōrite te papa hiko, arā, he ōrite puta noa, ko te whanaungatanga i waenganui i te papa hiko me te rerekētanga pūmanawa hiko ka whakaaturia i roto i te whārite V = E s ( kua kōrerohia tēnei whārite i roto i te rauemi pūmanawa hiko ). Mena he ōrite te kiato o te iahiko hiko, arā, he ōrite puta noa, ko te whanaungatanga i waenganui i te kiato o te iahiko me te iahiko hiko ka whakaaturia i roto i te whārite I = JA ( kua kōrerohia tēnei whārite i roto i te rauemi iahiko ).
Hei whiwhi i tētahi whārite e whakaatu ana i te whanaungatanga i waenga i te pūmanawa hiko (V), te iahiko hiko (I) me te ātete hiko (R), whakakapia a E me J i roto i te whārite ātete ki a E i roto i te whārite pūmanawa hiko, me J i roto i te whārite iahiko:
He whārite tēnei e whakamārama ana i te whanaungatanga i waenga i te pūmanawa hiko (V), te iahiko hiko (I) me te ātete hiko (R) i roto i te kaiārahi. I runga i tēnei whārite, ka taea te kī ko te ātete hiko i roto i te kaiārahi ko te ōwehenga o te rerekētanga pūmanawa hiko ki te iahiko i roto i te kaiārahi.
E ai ki te ture a Ohm he pumau te ōwehenga o te rerekētanga pūmanawa hiko ki te iahiko hiko. Arā, ka whakamāramahia e tēnei whārite te ture a Ohm ina pumau te ātete hiko (R). Kāore te ture a Ohm e pā ana ki te kore e pumau te ātete hiko, arā, ka rerekē.
I te whakaputanga o te whārite i runga ake nei, e pā ana hoki te ātete hiko (R) o te kaiārahi ki te ātete motuhake (ρ), te roa o te kaiārahi (l) me te horahanga whakawhiti-wāhanga (A) o te kaiārahi. Mā te pāngarau, ka whakaaturia tēnei i roto i te whārite:
Ka matapakihia tēnei whārite i roto i te tuhinga mō te ātete hiko.
Te Tātai Ture a Ohm
E rua ngā whārite e whakamāramahia ana te ture a Ohm, arā, ko ρ = E/J me R = V/I. Me mōhio ko ēnei whārite e rua he whārite ture a Ohm anake ina he pumau a ρ, ā, he pumau a R. Mena ka huri a ρ me R o tētahi kaiārahi, kāore ēnei whārite e whakamārama i te ture a Ohm, engari ko ρ = E/J e whakamārama ana i te ātete motuhake o tētahi kaiārahi, ā, ko R = V/I e whakamārama ana i te ātete hiko o tētahi kaiārahi.
Ka taea te tuhi i te whārite ρ = E/J pēnei i te E = ρ J. Ina pumau a ρ, ka ōrite tika a E ki a J, arā, ki te piki a E ka piki a J, ki te heke rānei a E ka heke a J.
Waihoki, ka taea te tuhi i te whārite R = V/I hei V = I R. Ina pumau a R, ka rite tonu te ōrite o V ki a I, arā, ki te piki a V, ka piki a I, ki te heke rānei a V, ka heke a I.
Ko ngā rauemi e tutuki ana i te ture a Ohm ka kiia he ohmic, ko ngā rauemi ia kāore e tutuki ana i te ture a Ohm ka kiia he nonohmic. He ohmic te nuinga o ngā kaiārahi whakarewa, ko ētahi atu rauemi ia he nonohmic.
I roto i ngā rauemi kore-ohmic, kāore te ātete hiko e pumau, engari ka rerekē i runga i te ia me te rerekētanga pūmanawa. Ko te tikanga, ki te rerekē te ia, ka rerekē anō hoki te ātete o te rauemi, ā, ki te rerekē te ngaohiko, ka rerekē anō hoki te ātete o te rauemi. Nā te mea he rerekē te ātete hiko, i roto i ngā rauemi kore-ohmic, kāore te ngaohiko (V) i te ōrite tika ki te ia (I).
Ngā kauwhata V, I me R
I roto i ngā rauemi ohmic, he pumau te ōwehenga o V ki I, e tohuhia ana e te rārangi tika. Ko ngā tauira o ngā rauemi ohmic ko ngā kaiārahi konganuku. I taua wā, i roto i ngā rauemi kore-ohmic, kāore te ōwehenga o V ki I i te pumau, e tohuhia ana e te rārangi piko. Ko ngā tauira o ngā rauemi kore-ohmic ko ngā diode semiconductor me ngā transistors.
Ko te ture a Ohm e pā ana ki ngā rauemi ohmic anake, ehara i te mea ki ngā rauemi katoa, nō reira he hē te kī he ture pērā i ngā ture a Newton, i ētahi atu ture ahupūngao rānei. Ko ngā ture ahupūngao e pā ana ki ngā mea katoa, ehara i te mea ki ētahi mea anake. Heoi, kua noho te whakamahinga o te ture a Ohm hei mahi noa, nō reira e kiia tonutia ana ko te ture a Ohm, mena ka maumaharahia ko te ture a Ohm e pā ana ki ngā mea ohmic anake. Haunga te ture a Ohm, ko tētahi atu tauira o te whakaaro hē ko te whakamahinga o te ture hau pai, te ture a Hooke rānei.
