Te mārama ki te kaha
Ka taea e te karāhe iti te pupuri i te iti o te wai, engari ka taea e te karāhe nui te pupuri i te nui ake. Ko te nui o te karāhe, ko te nui ake o te wai ka taea te pupuri. Nō reira, he kaha, he ine rānei mō te kaha pupuri wai o ia karāhe. Pērā i ngā karāhe, he kaha anō hoki ngā pūnga ki te penapena i te utu hiko me te pūngao pūmanawa hiko. Ko te kaha o te pūnga, ko te ine rānei i tōna kaha ki te penapena i te utu hiko me te pūngao pūmanawa hiko, ka kiia ko te capacitance.
Ngā āhuatanga e pā ana ki te kaha
Ko te rahi o te karāhe e pupuri ana i te wai ka whakatauhia e tōna rahinga. Ā, me pēhea ngā pūnga hiko? He aha te mea e whakatau ana i te rahi o te kaha o te pūnga hiko ki te pupuri i te utu hiko?
E whakaatu ana te pikitia i raro nei i tētahi pūnga hiko māmā e rua ngā pereti kawe hiko e wehea ana e tētahi tawhiti. I mua i te hono atu ki tētahi pūtake hiko, pērā i te pākahiko, ka kore he utu mō ngā pereti e rua. Kātahi ka honoa tētahi pereti ki te pito pai o te pākahiko, ā, ko tētahi ki te pito kino mā te whakamahi i ngā waea.
I muri i te hononga ki te pito pai o te pākahiko, ka kukume te utu pai o te pākahiko i ngā irahiko utu kino i runga i te pereti, ka neke atu ki te pito pai o te pākahiko. Nā tēnei ka kore he irahiko (utu kino) o te pereti, ā, ka nui rawa ngā porotona (utu pai), ka hua ake he utu pai.
Waihoki, i muri i te honotanga o te pereti ki te pito kino o te pākahiko, ka kukume te utu pai i runga i te pereti i ngā irahiko utu kino i runga i te pito kino o te pākahiko, ka neke ngā irahiko ki te pereti. Mā tēnei ka nui rawa ngā irahiko o te pereti, ka utu kino.
Ka mutu te tukanga whakawhiti irahiko i waenga i ngā pereti me te pākahiko ina ōrite te rerekētanga pūmanawa i waenga i ngā pereti e rua ki te rerekētanga pūmanawa i waenga i ngā pou e rua o te pākahiko.
Me pēhea te pikinga o te utu hiko i runga i ngā pereti arataki e rua? Arā, me aha kia puta ai te whakawhiti irahiko anō? Ka puta te whakawhiti irahiko ina nui ake te rerekētanga pūmanawa hiko i waenga i ngā pou e rua o te pākahiko i te rerekētanga pūmanawa hiko i waenga i ngā pereti arataki e rua. Kia puta anō te whakawhiti irahiko kia piki ake ai te utu hiko i runga i ia pereti arataki, ka whakakapia te pākahiko e whakamahia ana ki tētahi atu pākahiko, ki tētahi atu pūtake ngaohiko rānei he nui ake te rerekētanga pūmanawa hiko. Ka mutu te whakawhiti irahiko ina ōrite te rerekētanga pūmanawa o te pūtake ngaohiko ki te rerekētanga pūmanawa o te pūnga, nō reira, ki te nui ake te rerekētanga pūmanawa o te pūtake ngaohiko, ka nui ake hoki te rerekētanga pūmanawa o te pūnga.
I runga i te arotake i runga ake nei, ka taea te whakatau ko te nui ake o te utu hiko e rongoa ana i runga i ia pereti arataki, ka nui ake te rerekētanga pūmanawa hiko i waenga i ngā pereti arataki e rua. Nō reira, he ōrite te utu hiko (Q) ki te rerekētanga pūmanawa hiko (V). Ko te whanaungatanga i waenga i te utu hiko me te rerekētanga pūmanawa hiko e whakaatuhia ana i roto i te ōwehenga e whai ake nei:
Q α V
Ka hurihia te ōwehenga o runga ake nei hei whārite mā te tāpiri i te pūmau ōwehenga C:
Q = CV, C = Q / V rānei
Whakaahuatanga: Q = utu hiko (Coulomb), V = rerekētanga pūmanawa hiko, ngaohiko hiko rānei (Volt), C = pūmau taurite, e kiia nei ko te kaha o te pūnga.
Kāore te uara o te kaha e whakawhirinaki ana ki te utu hiko me te ngaohiko engari e whakawhirinaki ana ki te āhua me te rahi o ngā pereti arataki. Kei roto i te tuhinga te whakamārama pāngarau e whakaatu ana ko te kaha e whakawhirinaki ana ki te āhua me te rahi o ngā pereti arataki e pā ana ki ngā momo kaha e ahu mai ana i te āhua o ngā pereti arataki, arā, ko ngā kaha pereti whakarara , ko ngā kaha porotaka , me ngā kaha porowhita . I roto i te tuhinga, e whakaarohia ana he korehau kei waenganui i ngā pereti arataki e rua.
Ko te kaha o te pūnga hiko e whakawhirinaki ana ki ngā āhuatanga o te rauemi i waenganui i ngā pereti kawe hiko e rua. Ko te rauemi i waenganui i ngā pereti kawe hiko e rua e kiia ana ko te dielectric . Ka matapakihia te kaha o te pūnga hiko me te dielectric i roto i te tuhinga mō te pūmau dielectric.
Te waeine o te kaha
Ko te waeine o te utu hiko ko te Coulomb, ā, ko te waeine o te rerekētanga pūmanawa hiko ko te Volt, nō reira, i runga i te whārite capacitance i runga ake nei, ko te waeine o te capacitance ko te Coulomb per Volt (C/V), e kiia ana ko Farad (F) i ahu mai i te ingoa o te kaipūtaiao Peretānia a Michael Faraday (1791-1867). Nō reira, 1 Farad = 1 Coulomb/Volt.
Hei tauira, ko te uara o te pūnga hiko he 2 Farads, ko te tikanga ka rongoa e te pūnga hiko he utu hiko o te +2 Coulombs i runga i tētahi o ngā pereti kawe hiko me te -2 Coulombs i runga i tētahi atu pereti kawe hiko, kei reira te rerekētanga pūmanawa o ngā pereti kawe hiko e rua he 1 Volt. Mena ka honoa he pākahiko 12 Volt ki te pūnga hiko, ka whai utu hiko tētahi o ngā pereti kawe hiko o Q = CV = (2)(12 Volts) = +24 Coulombs, ko te utu o tētahi atu pereti kawe hiko he -24 Coulombs.
Me mōhio ko te Farad he waeine tino nui o te kaha, nō reira ka whakamahia ngā waeine iti ake, arā, ko te microFarad kua whakarapopototia ki te μF (10 -6 Farad) ki te picoFarad kua whakarapopototia ki te pF (10 -12 Farad). Ka matapakihia ngā tātaitanga pāngarau hei whakaatu i te Farad he waeine tino nui i roto i te tauira o te kaha pereti whakarara.
