Fahimtar Dokar Ohm
Haka kuma yi nazarin kayan da ke kan tambayoyin misalin dokar Ohm da tattaunawa kan tambayoyin dokar Ohm.
A kusan dukkan na'urorin sarrafa ƙarfe, filin lantarki daidai da yawan wutar lantarki, inda rabon filin lantarki da yawan wutar lantarki yake daidai. An bayyana shi ta hanyar lissafi ta hanyar lissafi:
ρ = E / J
Bayani: E = filin lantarki, ρ = juriya, J = yawan wutar lantarki.
Ana kiran daidaitaccen daidaito ρ da takamaiman juriya ko juriya, ƙimarsa ta kasance mai dorewa kuma ba ta dogara da filin lantarki da ke samar da wutar lantarki ba.
Idan filin lantarki ya ƙaru, yawan wutar lantarki ma yana ƙaruwa, akasin haka, idan filin lantarki ya ragu, yawan wutar lantarki ma yana raguwa, don haka rabon filin lantarki zuwa yawan wutar lantarki ya kasance mai ɗorewa. Wannan sanarwa ce ta dokar Ohm . Don haka lissafin da ke sama yana bayyana dokar Ohm ne kawai lokacin da ρ ya kasance mai ɗorewa kuma ba shi da alaƙa da filin lantarki. Dokar Ohm ba ta aiki idan ƙimar ρ ta canza lokacin da filin lantarki ya canza.
Duk da haka, yana da sauƙi a auna ƙarfin lantarki (V) fiye da filin lantarki (E), kuma yana da sauƙi a auna ƙarfin lantarki (I) fiye da yawan ƙarfin lantarki (J). Saboda haka, baya ga bayyanawa dangane da filin lantarki , yawan ƙarfin lantarki da juriya (ρ), dokar Ohm kuma an bayyana ta dangane da ƙarfin lantarki , ƙarfin lantarki da juriyar lantarki (R).
Da farko, yi la'akari da jagorar waya wacce ke da tsayi (l), yanki mai giciye (A) kuma akwai bambancin yuwuwar lantarki (V) tsakanin ƙarshen waya biyu. Idan filin lantarki ya yi kama da juna, wanda aka fi sani da iri ɗaya a ko'ina, to dangantakar da ke tsakanin filin lantarki da bambancin yuwuwar lantarki za a bayyana ta a cikin lissafi V = E s ( an tattauna wannan lissafi a cikin kayan yuwuwar lantarki ). Idan yawan kwararar lantarki ya yi kama da juna, wanda aka fi sani da iri ɗaya a ko'ina, to dangantakar da ke tsakanin yawan kwararar lantarki da kwararar lantarki za a bayyana ta a cikin lissafi I = JA ( an tattauna wannan lissafi a cikin kayan yuwuwar lantarki ).
Domin samun lissafi wanda ke nuna alaƙar da ke tsakanin ƙarfin lantarki (V), ƙarfin lantarki (I) da juriyar lantarki (R), maye gurbin E da J a cikin lissafin juriya da E a cikin lissafin ƙarfin lantarki da J a cikin lissafin ƙarfin lantarki:
Wannan lissafi ne da ke bayyana alaƙar da ke tsakanin ƙarfin lantarki (V), ƙarfin lantarki (I) da juriyar lantarki (R) a cikin mai jagora. Dangane da wannan lissafi, za a iya cewa juriyar lantarki a cikin mai jagora shine rabon bambancin ƙarfin lantarki da ƙarfin lantarki a cikin mai jagora.
Dokar Ohm ta bayyana cewa rabon bambancin ƙarfin lantarki da wutar lantarki mai dorewa ne. A wata ma'anar, wannan lissafin yana bayyana dokar Ohm ne kawai lokacin da juriyar lantarki (R) take dawwama. Dokar Ohm ba ta aiki idan juriyar lantarki ba ta dawwama ba, wato, tana bambanta.
A cikin tsarin lissafin da ke sama, juriyar wutar lantarki (R) na mai jagora yana da alaƙa da takamaiman juriya (ρ), tsawon mai jagora (l) da yankin giciye (A) na mai jagora. A lissafi, an bayyana wannan a cikin lissafin:
An tattauna wannan lissafi dalla-dalla a cikin labarin kan juriyar wutar lantarki.
Tsarin Dokar Ohm
An bayyana dokar Ohm ta hanyar lissafi biyu, wato ρ = E/J da R = V/I. Ya kamata a lura cewa waɗannan lissafi guda biyu lissafin dokar Ohm ne kawai lokacin da ρ yake da daidaito kuma R shine da daidaito. Idan ρ da R na mai jagoranci suka canza, waɗannan lissafi guda biyu ba sa bayyana dokar Ohm, amma ρ = E/J yana bayyana takamaiman juriyar mai gudanarwa kuma R = V/I yana bayyana juriyar wutar lantarki na mai gudanarwa.
Ana iya rubuta lissafin ρ = E/J a matsayin E = ρ J. Idan ρ ya kasance mai daidaito to E yana daidai da J kai tsaye, ma'ana idan E ya ƙaru to J yana ƙaruwa ko kuma idan E ya ragu to J yana raguwa.
Haka nan, ana iya rubuta lissafin R = V/I a matsayin V = I R. Idan R ya kasance mai daidaito, V yana daidai gwargwado kai tsaye da I, ma'ana idan V ya ƙaru, I ya ƙaru, ko kuma idan V ya ragu, I ya ragu.
Ana cewa kayan da ke bin dokar Ohm suna da ohmic, yayin da kayan da ba sa bin dokar Ohm ake cewa ba su da ohmic. Kusan dukkan masu amfani da ƙarfe suna da ohmic, yayin da sauran kayan da yawa ba su da ohmic.
A cikin kayan da ba na ohmic ba, juriyar lantarki ba ta canzawa ba, amma ta bambanta dangane da bambancin yanzu da kuma yiwuwar hakan. Wannan yana nufin cewa idan wutar lantarki ta canza, juriyar kayan ma tana canzawa, haka nan ma, idan wutar lantarki ta canza, juriyar kayan ma tana canzawa. Saboda juriyar lantarki ta bambanta, a cikin kayan da ba na ohmic ba, ƙarfin lantarki (V) ba ya daidaita kai tsaye da wutar lantarki (I).
Jadawalin V, I da R
A cikin kayan ohmic, rabon V zuwa I yana dawwama, wanda aka wakilta ta hanyar layi madaidaiciya. Misalan kayan ohmic sune masu jagoranci na ƙarfe. A halin yanzu, a cikin kayan nohmic, rabon V zuwa I ba maiwwama ba ne, wanda aka wakilta ta hanyar layi mai lanƙwasa. Misalan kayan nohmic sune diodes na semiconductor da transistors.
Dokar Ohm ta shafi kayan ohmic ne kawai ba ga dukkan kayan ba, don haka ba daidai ba ne a kira ta doka kamar dokokin Newton ko wasu dokokin kimiyyar lissafi. Dokokin kimiyyar lissafi a zahiri sun shafi dukkan abubuwa, ba ga wasu abubuwa kawai ba. Duk da haka, amfani da dokar Ohm ya zama ruwan dare gama gari, don haka har yanzu ana kiranta dokar Ohm, matuƙar ana tuna cewa dokar Ohm ta shafi abubuwa ohmic ne kawai. Bayan dokar Ohm, wani misali na kuskuren fahimta shine amfani da dokar iskar gas mai kyau ko dokar Hooke.
