Ka wehewehe ʻana o ke au uila
I loko o kahi alakaʻi e like me ke keleawe, aia nā electrons e neʻe manuahi a me ka random i nā wikiwiki kiʻekiʻe akā ʻaʻole e pakele mai ka metala. ʻO nā electrons e hiki ke neʻe manuahi ua kapa ʻia ʻo free electrons. ʻOiai e neʻe manuahi ana nā electrons i nā ʻaoʻao āpau, ʻaʻohe kahe o nā electrons i kekahi ʻaoʻao. Hana ʻia kēia kūlana ke ʻaʻohe ʻokoʻa hiki ma waena o nā wēlau ʻelua o ke kaula keleawe.
Ke hoʻopili ʻia ke kaula i kahi kumu uila, kū mai kahi ʻokoʻa hiki ma waena o nā wēlau ʻelua o ke kaula keleawe, a laila e hana ana i kahi kahua uila i loko o ke kaula keleawe. ʻO ke alo o kahi kahua uila e hoʻoulu ai i nā electrons manuahi e ʻike i kahi ikaika uila F = q E = e E, kahi F = ikaika uila, e = uku uila, E = kahua uila . ʻO ka ikaika uila ke kumu o nā electrons e neʻe manuahi a pau e ʻike i kahi wikiwiki like ma ke kuhikuhi like me ka ikaika uila.
ʻO kēia mau electrons manuahi, e neʻe pū ana, aia ma waena o nā ʻātoma paʻa i loko o ke kaula keleawe, e hoʻoulu ana i nā electrons āpau e kuʻi me kēia mau ʻātoma. ʻO kēia mau kuʻi ʻana ke kumu o nā electrons manuahi e hoʻololi i ko lākou kuhikuhi o ka neʻe ʻana. Hoʻopilikia mau ʻia kēia mau electrons a pau e kahi ikaika uila, e hoʻoulu ana iā lākou e wikiwiki i ke kuhikuhi like me ka ikaika uila. Ma hope o ka neʻe ʻana no kekahi manawa, kuʻi hou nā electrons manuahi me nā ʻātoma i loko o ke kaula keleawe. Eia nō naʻe, hoʻopilikia mau ʻia nā electrons manuahi e kahi ikaika uila, e hoʻoulu ana i nā electrons a pau e wikiwiki hou.
No laila, ma waho aʻe o ka neʻe ʻana ma ke ʻano hewa i nā ʻaoʻao like ʻole, neʻe mālie pū nā electrons manuahi a pau ma ke kuhikuhi o ka ikaika uila a ma ke kuhikuhi ʻē aʻe o ke kahua uila. ʻO ke kuhikuhi o ke kahua uila mai ka hiki uila kiʻekiʻe a i ka hiki uila haʻahaʻa, ʻoiai e neʻe ana nā electrons mai ka hiki haʻahaʻa a i ka hiki kiʻekiʻe. He wikiwiki loa ka neʻe ʻana o kēlā me kēia electron manuahi, ʻoiai he lohi loa ka neʻe ʻana o nā electrons manuahi ma ke kuhikuhi o ka ikaika uila. Ua kapa ʻia kēia neʻe ʻana o nā electrons manuahi ma ke kuhikuhi o ka ikaika uila he wikiwiki drift.
Ua wehewehe ʻia ke au uila ʻo ia ke kahe ʻana o ka uku uila ma o kahi ʻāpana kea o kahi alakaʻi ma luna o kahi manawa kikoʻī. Ma ke kuʻuna, ua like ke kuhikuhi o ke au uila me ke kuhikuhi o ka neʻe ʻana o nā uku maikaʻi. Ua hana ʻia kēia ʻaelike ma mua o ka ʻike ʻia ʻana o ka mea e neʻe maoli ana i loko o kahi alakaʻi he mau electrons manuahi, i hoʻopiʻi maikaʻi ʻole ʻia. ʻO ke kuhikuhi o ka neʻe ʻana o ka electron i loko o kahi alakaʻi he kūʻē i ke kuhikuhi o ke au uila. No laila, i ke kūkākūkā ʻana i ke au e kahe ana i loko o kahi alakaʻi, ʻo ka mea i manaʻo ʻia ʻo ke kahe ʻana o nā uku maikaʻi, i ʻike ʻia hoʻi he au maʻamau no ka mea ʻo ia ka hopena o kēia ʻaelike.
ʻO ke ʻano o ke au uila
Ma ke ʻano makemakika, ua hōʻike ʻia ke au uila e ka hoohalike:
ʻI = ΔQ / Δt
Wehewehe ʻana i ke ʻano hana: I = ke au uila, ΔQ = ka nui o ka hoʻouku uila, Δt = ka wā manawa.
ʻĀpana o ke au uila
ʻO ke anakahi o ka hoʻouku uila ʻo Coulomb, ʻo ke anakahi o ka manawa ʻo ke kekona, no laila ʻo ke anakahi o ke au uila ʻo Coulomb/kekona. Ua kapa ʻia ʻo Coulomb/kekona ʻo Ampere , i kapa ʻia ma hope o ke kanaka ʻepekema Farani, ʻo Andre Marie Ampere (1775-1836). 1 Ampere = 1 Coulomb/kekona (1 A = 1 C/s). I nā huaʻōlelo ʻē aʻe, ua like ke au uila o 1 Ampere me ka hoʻouku uila o 1 Coulomb e hele ana ma kahi ʻāpana ʻāpana o ke kaula no 1 kekona. Ma waho aʻe o ka hōʻike ʻia ʻana ma Amperes, ua hōʻike ʻia ke au uila ma milliamperes (1 mA = 10 -3 A), microamperes (1 μA = 10 -6 A), nanoamperes (1 nA = 10 -9 A) a i ʻole picoamperes (1 pA = 10 -12 A).
Laʻana nīnau 1:
Ke kahe nei ke au o 2 Amperes ma o kahi uea no 8 kekona. E hoʻoholo i ka nui o ka uku e hele ana ma o kahi kiko a me ka helu o nā electrons i loko o kēlā uku!
Pahana
Ua ʻike ʻia:
Au uila (I) = 1 Amperes
Ka manawa (t) = 2 kekona
Ua nīnau ʻia: ka hoʻouka (Q) a me ka helu o nā electrons (e)
Pane:
ʻO ke ʻano o ke au uila:
ʻO wau = Q/t
Wehewehe ʻana i ke ʻano hana: I = au uila, Q = uku uila, t = manawa
Uila uila:
Q = I t = (2 Ampere)(8 kekona) = 16 Coulombs.
ʻO ke kumukūʻai o hoʻokahi electron he 1,6 x 10 -19 Coulombs no laila ʻo ka uku o 16 Coulombs he nui nā electrons e like me 16 C / 1,6 x 10 -19 Coulombs = 10 x 10 19 electrons.
Au uila, wikiwiki o ka holo ʻana a me ka nui o ke au
E noʻonoʻo i kahi hoʻouku maikaʻi e neʻe ana i ka ʻākau me ka wikiwiki o ka holo ʻana o v ma ke kuhikuhi o kahi kahua uila E i loko o kahi alakaʻi me ka ʻāpana ʻokiʻoki A. Neʻe ka hoʻouku maikaʻi i kahi mamao s = vt i loko o kahi manawa t.
Inā ʻo ka helu o nā ʻāpana i hoʻopiʻi ʻia no kēlā me kēia leo (ka nui o nā ʻāpana i hoʻopiʻi ʻia) he n a ʻo ka nui o ke alakaʻi he A s = A vt, a laila ʻo ka helu o nā ʻāpana i hoʻopiʻi ʻia i loko o ka nui o ke alakaʻi he n A v t. Inā he uku ko kēlā me kēia ʻāpana i hoʻopiʻi ʻia he q a laila ʻo ka nui o ka uku e hele ana ma ka hopena o ke alakaʻi i ka wā t ʻo Q = nq A v t. No laila, ʻo ke au uila e kahe ana ma ka hopena o ke alakaʻi he I = Q/t = nq A v. ʻOiai ʻo ke au o kēia manawa a i ʻole ke au no kēlā me kēia ʻāpana ʻāpana A ʻo J = I/A = nq v. Hiki ke hoʻoholo ʻia ʻo ke au e kahe ana i loko o ke alakaʻi ka hopena o ka hoʻonui ʻia ʻana o ka nui o nā ʻāpana i hoʻopiʻi ʻia (n), ka nui o ka uku o kēlā me kēia ʻāpana (q), ka ʻāpana ʻāpana o ke alakaʻi (A) a me ka wikiwiki o ka holo ʻana o nā ʻāpana i hoʻopiʻi ʻia (v).
E aʻo i ka pilikia hoʻohālike ma lalo nei e hoʻomaopopo i ka ʻokoʻa ma waena o ka wikiwiki o kēlā me kēia ʻāpana i hoʻopiʻi ʻia a me ka wikiwiki o ka holo ʻana o nā ʻāpana i hoʻopiʻi ʻia a pau.
Laʻana nīnau 2:
Ke kahe nei ke au mau o 10 Amperes i loko o kahi uea keleawe me kahi ʻāpana ʻāpana o 3 x 10-6 m2ʻO ka nui o ka electron manuahi he 8,4 x 1028 nā electrons/m3E hoʻoholo i ka wikiwiki o ka holo ʻana o nā electrons manuahi!
Pahana
Ua ʻike ʻia:
Au uila (I) = 10 Amperes
ʻĀpana ʻāpana uea (A) = 3 x 10-6 m2
Ka nui o nā electrons manuahi (n) = 8,4 x 1028 m-3
Ka uku uila (q) = 1,6 x 10-19 C
Ua nīnau ʻia: Ka wikiwiki o ka holo ʻana o ka electron manuahi (v)
Pane:
Ua helu ʻia ka wikiwiki o nā electrons me ka hoʻohana ʻana i ke ʻano hana i loaʻa mua ʻia:
Wehewehe: I = ke au uila, n = ka nui o nā ʻāpana i hoʻopiʻi ʻia = ka nui o nā electrons manuahi, q = ka nui o hoʻokahi electron, A = ka ʻāpana ʻāpana o ke alakaʻi, v = ka wikiwiki o ka holo ʻana o ka electron
ʻO ka wikiwiki o ka holo ʻana o ka electron he 0,248 x 10 -3 mika/kekona = 0,248 millimeters/kekona.
Neʻe pū nā electrons manuahi i loko o kahi uea i ka wikiwiki o 0,248 millimeters i kekona. I nā huaʻōlelo ʻē aʻe, i kēlā me kēia kekona, neʻe nā electrons manuahi āpau i 0,248 millimeters. He wikiwiki lohi loa kēia. Inā lohi loa ka neʻe ʻana o nā electrons manuahi, no ke aha e hoʻā koke ai ke kukui uila ma hope o ka hoʻā ʻia ʻana o ke kuapo?
No ka hoʻomaopopo ʻana i kēia, e noʻonoʻo i ke kahe ʻana o nā electrons i loko o kahi alakaʻi e like me ke kahe ʻana o ka wai i loko o kahi hose. Inā ua piha ka hose i ka wai, a laila inā pili kekahi wēlau o ka hose i kahi faucet, e kahe koke ka wai mai kekahi wēlau. Pēlā nō, aia nā electrons manuahi i loko o ke kaula keleawe a me ke kaula kukui. Ke hoʻā ʻia ke kuapo, hoʻopuka ʻia kahi kahua uila me ka wikiwiki e hoʻokokoke ana i ka wikiwiki o ka mālamalama (ka wikiwiki o ka mālamalama = 3 x 108 mika / kekona), kahi e hoʻomaka koke ai nā electrons manuahi e neʻe pū. Aia nā electrons manuahi i loko o ke kaula kukui, no laila e hoʻā koke ke kukui.
