Ukumelana nogesi kuwumqondo obalulekile ku-physics kanye nobunjiniyela kagesi. Kunquma ukuthi ugesi uzovinjelwa kangakanani uma udlula ezintweni. Kulesi sihloko, sizoxoxa ngokujulile ngokumelana kwengxenye yentambo yokuqhuba. Sizohlanganisa incazelo eyisisekelo, izici ezithinta ukumelana, kanye nemithetho eyisisekelo yokumelana. Sizohlola nezindlela ezisebenzayo zokulinganisa ukumelana.
Umqondo Oyisisekelo Wokumelana Nogesi
Ukumelana kukagesi (R) kuyisilinganiso sokuthi impahla iphikisana kangakanani nokugeleza kwamandla kagesi. Ukumelana kukalwa ngama-ohms (Ω), aqanjwe ngesazi sefiziksi saseJalimane uGeorg Simon Ohm. Umthetho ka-Ohm uthi ukumelana (R) kusekethe kuyisilinganiso se-voltage (V) kumandla kagesi (I):
\[ R = \frac{V}{I} \]
Di mana:
– \( V \) yi-voltage (kuma-volts)
– \( I \) ingumshini wamanje (ngama-ampere)
– \( R \) ukumelana (kuma-ohms)
Izici Ezithinta Ukumelana Kwezintambo Zomqhubi
Ukumelana kwengxenye yentambo yokuqhuba kuthonywa yizici eziningana, okuhlanganisa:
1. Uhlobo Lwezinto: Izinto ngazinye zinokuphikiswa okuhlukile (ρ). Ukuphikiswa kuyindlela yokulinganisa ikhono lento ethile lokuqhuba ugesi. Izinsimbi ezifana nethusi ne-aluminium zinokuphikiswa okuphansi, kuyilapho izivikeli ezifana nerabha zinokuphikiswa okuphezulu.
2. Ubude Bentambo (L): Ukumelana kwentambo kuhambelana nobude bentambo. Uma intambo inde, ukumelana kwayo kukhulu.
\[ R \propto L \]
3. Indawo Enqamula Izintambo (A): Ukumelana nezintambo kuhambelana nendawo enqamula izintambo. Uma indawo enqamula izintambo inkulu, ukumelana kuncane.
\[ R \propto \frac{1}{A} \]
4. Izinga Lokushisa: Ukumelana kwentambo nakho kuyathinteka yizinga lokushisa. Eziningi zezinsimbi, ukumelana kuyanda ngokushisa okwandayo. Ngokuphambene nalokho, kwezinye izinto ze-semiconductor, ukumelana kuyancipha ngokushisa okwandayo.
Isilinganiso Sokumelana Nezintambo Zomqhubi
Ukumelana kwengxenye yentambo yokuqhuba kungabalwa kusetshenziswa i-equation elandelayo:
\[ R = \rho \frac{L}{A} \]
Di mana:
– \( R \) ukumelana (kuma-ohms)
– \( \rho \) ukuqina kwezinto (kumamitha e-ohm)
– \( L \) ubude bentambo (ngamamitha)
– \( A \) yindawo enqamula ingxenye yentambo (ngamamitha-skwele)
Izinhlobo Zezinto Ezisetshenziswayo Nokumelana Kwazo
Okulandelayo ezinye zezinto ezivamile ezisetshenziswa njengabaqhubi bakagesi kanye namanani azo okumelana nogesi:
1. Ithusi (Cu): Ithusi liyi-conductor kagesi enhle kakhulu enokumelana cishe okungu-1.68 \times 10^{-8} \) ohm metres ekushiseni kwegumbi.
2. I-Aluminium (Al): I-Aluminium futhi iyi-conductor enhle, yize iphansi kancane kunethusi, inokumelana okucishe kube yi-\( 2.82 \times 10^{-8} \) ohm metres.
3. Isiliva (Ag): Isiliva sinamandla okumelana aphansi kakhulu angaba ngu-1.59 \times 10^{-8} \) ohm meter, kodwa ukusetshenziswa kwaso kunqunyelwe ngenxa yezindleko zaso eziphezulu.
4. Insimbi (Fe): Insimbi inokumelana okuphezulu okungaba yi-\( 9.71 \times 10^{-8} \) ohm meter, evame ukusetshenziswa ezinhlelweni lapho izindleko zibaluleke kakhulu kunokusebenza kahle.
Umphumela Wokushisa Ekumelaneni
Ukumelana kwentambo eqhubayo kuvame ukwanda ngokushisa okwandayo. Lokhu kungenxa yokudlidliza okwandisiwe kwama-athomu entanjeni, okuvimbela ukugeleza kwama-electron. Ubudlelwano phakathi kokumelana nokushisa bungabonakaliswa yi-equation elandelayo:
\[ R_T = R_0 (1 + \alpha (T – T_0)) \]
Di mana:
– \( R_T \) ukumelana ekushiseni \( T \)
– \( R_0 \) ukumelana ekushiseni okubhekiselwe \( T_0 \)
– \( \alpha \) yisilinganiso sokumelana nokushisa (ngamadigri Celsius)
– \( T \) izinga lokushisa ngamadigri Celsius
– \( T_0 \) izinga lokushisa elibhekiselwe kuma-degree Celsius
I-coefficient yokushisa yokumelana (\(\alpha\)) iyahlukahluka ngento ngayinye. Isibonelo, ngethusi, \(\alpha\) cishe ingama-0.00393 \) nge-degree Celsius.
Ukusetshenziswa Okusebenzayo Kokumelana Nezintambo Zomqhubi
Ukumelana kwezintambo eziqhubayo kunezindlela eziningi ezisebenzayo empilweni yansuku zonke nasembonini, okuhlanganisa:
1. Amakhebula Kagesi: Amakhebula kagesi emakhaya nasezimbonini asebenzisa izintambo zokulawula ugesi eziqinile ukuqinisekisa ukusebenza kahle okuphezulu kanye nokulahlekelwa kwamandla okuncane.
2. Ama-Heater kagesi: Ama-heater kagesi asebenzisa izintambo ezithwala umoya ezinamandla amakhulu ukuze akhiqize ukushisa lapho ugesi ugeleza kuzo.
3. Ama-electrode kumabhethri: Ama-electrode kumabhethri enziwe ngezinto ezinokumelana okuthile ukulawula ukuhamba kwamandla kagesi kanye ne-voltage ngesikhathi senqubo yokushaja nokukhipha amandla.
4. Uhlelo Lukagesi Lwezimoto: Uhlelo lukagesi emotweni lusebenzisa ama-conductor anamandla aphansi ukunciphisa ukulahleka kwamandla nokuqinisekisa ukusebenza kahle.
Ukulinganisa Ukumelana Nentambo Yomqhubi
Ukulinganisa ukumelana kwentambo yokuqhuba kungenziwa kusetshenziswa ithuluzi elifana ne-ohmmeter noma i-multimeter. Nazi izinyathelo eziyisisekelo zokulinganisa ukumelana:
1. Cima amandla wesekethe: Qiniseka ukuthi akukho ugesi ogeleza esekethe ngaphambi kokulinganisa ukumelana.
2. Xhuma Ithuluzi Lokulinganisa: Xhuma i-ohmmeter noma i-multimeter kuzo zombili izinhlangothi zentambo ofuna ukukala ukumelana kwayo.
3. Funda Imiphumela Yokulinganisa: Imiphumela yokulinganisa ukumelana izoboniswa esikrinini sedijithali sethuluzi lokulinganisa.
Izilinganiso zokumelana nazo zingenziwa kusetshenziswa indlela ye-Wheatstone bridge, enikeza imiphumela enembile kakhulu yokumelana okuncane kakhulu.
Amaphutha Nokungaqiniseki Ekulinganisweni Kokumelana
Izilinganiso zokumelana zingathonywa yizici eziningana ezibangela amaphutha nokungaqiniseki, okuhlanganisa:
1. Ukulinganisa Amathuluzi Okulinganisa: Amathuluzi okulinganisa angalinganiswanga kahle anganikeza imiphumela yokulinganisa enganembile.
2. Ukuxhumeka Okungafanele: Ukuxhumeka okuxegayo noma okungafanele kungathinta imiphumela yokulinganisa ukumelana.
3. Umphumela Wezinga Lokushisa: Izinguquko ekushiseni ngesikhathi sokulinganisa zingathinta ukumelana kwezinto, futhi ngenxa yalokho, ukumelana okulinganisiwe.
4. Izimo Zemvelo: Izimo zemvelo ezifana nomswakama kanye nomfutho womoya nazo zingathinta imiphumela yokulinganisa.
Ukuze kuncishiswe amaphutha, kubalulekile ukusebenzisa amathuluzi okulinganisa alinganiswe kahle, ukuqinisekisa ukuxhumana okufanele, nokwenza izilinganiso endaweni elawulwayo.
Isiphetho
Ukumelana kwentambo yokuqhuba kuyinto ebalulekile kwisayensi kagesi kanye nobunjiniyela kagesi. Ukumelana kuthinteka uhlobo lwezinto, ubude bentambo, indawo enqamulayo, kanye nokushisa. Isibalo esiyisisekelo esihlobana nalezi zici yi-\( R = \rho \frac{L}{A} \). Ukuqonda ukumelana kwentambo yokuqhuba kubalulekile ekwakhiweni nasekuthuthukiseni izinhlelo zikagesi ezinhlobonhlobo zezicelo ezisebenzayo. Ukulinganisa ukumelana kudinga amathuluzi afanele kanye nokunaka izinto ezingathinta ukunemba kokulinganisa. Ngale ndlela yokuqonda, singaqinisekisa ukusebenza kahle kanye nokusebenza kahle kwezinhlelo zikagesi esizisebenzisa nsuku zonke.
