Kirchhoff txoj cai nyob rau hauv elekrotehnike

Nyob rau hauv cov lus teb ntawm hluav taws xob circuits AC thiab DC dua li nto moo mis Ohm kuj thov Kirchhoff txoj kev cai. Tus txiv neej, uas nws ua hauj lwm muaj feem xyuam rau cov hluav taws xob engineering, yuav tsum txawm thaum hmo ntuj tsis muaj hesitation muab txhais cov ntsiab lus rau txhua tus ntawm ob txoj kev cai. Feem ntau nws yog tsis tsim nyog los ua suav ntau li ntau raws li rau qhov kev nkag siab ntawm lub dab.

Rov qab nyob rau hauv 1845, lub German physicist Gustav Kirhgof raws li Maxwell tej hauj lwm (kev txuag xwb, thiab thaj chaw ntawm lub electrostatic teb) formulated ob kev cai rau specifying lub kev sib raug zoo ntawm cov voltage thiab tam sim no nyob rau hauv lub kaw hluav taws xob Circuit Court. Qhov no ua rau nws tau los daws kom tau yuav luag txhua daim ntawv thov teeb meem muaj feem xyuam rau hluav taws xob. Kirchhoff txoj cai yog siv los mus xam cov linear fais Circuit Court, nws enables mus muab tau cov classical system ntawm linear equations uas coj mus rau hauv tus account lub voltages thiab currents uas ua paub tom qab ua hauj lwm.

Cov hais qhia kev siv ntawm cov nqe lus hluav taws xob "Circuit Court ntawm thiab ceg." Ceg - yog tej double-tog Circuit Court txoj kev, ib tug arbitrary ntev ntawm nws. Circuit Court - ib tug system obsessed ceg, uas yog, pib ib puas siab puas ntsws zog ntawm tej taw tes rau tej ceg, nyob rau hauv lub kawg tseem tau txais mus rau hauv lub qhov chaw uas lub zog pib. Ntau to taub ceg hu ua "yob tshaj", Txawm tias qhov no yog tsis nkaus muaj tseeb. Ntawm - ib tug taw tes thaum uas ob tug los yog ntau tshaj ceg.

1 Kirchhoff txoj cai yog heev yooj yim. Nws yog raws li nyob rau hauv qhov siv txoj cai lij choj ntawm kev txuag xwb. Kirchhoff tus thawj txoj kev cai hais tias: lub sum ntawm currents (algebraic), sau cia rau hauv ceg mus rau ib tug ib node yog sib npaug zos rau zero. Hais tias yog, I1 + I2 + I3 = 0. Rau cov lus teb nws yog lam xav hais tias tus nqi ntawm currents ntws mus rau hauv node muaj ib tug "+" kos npe rau thiab lub resulting "-". Yog li ntawd, cov mis mos yuav ib txhab view ntawm I1 + I2 - I3 = 0. Nyob rau hauv lwm yam lus, tus nqi ntawm cov tam sim no ntws mus rau hauv ib tug node yog sib npaug zos rau cov xov tooj ntawm effluent. Qhov no Kirchhoff txoj cai tseem ceeb heev rau kev nkag siab txog lub hauv paus ntsiab lus ntawm hluav taws xob khoom. Piv txwv li, nws piav yog vim li cas thaum txuas lub electric tsav windings rau ib tug "lub hnub qub" los yog "daim duab peb sab" yog tsis muaj interphase luv luv Circuit Court.

2 Kirchhoff txoj cai yog feem ntau yog siv los mus laij lub voj kaw nrog ib tug tej tus nqi ntawm ceg. Nws yog ncaj qha correlated nrog peb kev cai lij choj ntawm Maxwell (qhov magnetic teb). Cov cai hais tias cov algebraic sum ntawm cov voltage dauv txhua yam ntawm tus Circuit Court ceg yog sib npaug zos rau cov sum ntawm cov emf qhov tseem ceeb payment rau tag nrho cov ceg ntawm cov Circuit Court. Nws yog pom tseeb tias nyob rau hauv lub qhaj ntawv ntawm ib tug kaw Circuit Court ntawm hluav taws xob hwj chim qhov twg los (Eds), lub resulting voltage nco yuav kuj yuav pes tsawg. Nyob rau hauv ntau yam yooj yim cov ntsiab lus, cov chaw ntawm lub zog yog tsuas yog hloov dua siab tshiab rau tus neeg, thiab aims ntawm rov mus rau cov thawj cov nqi. Siv txoj kev cai no muaj ib tug xov tooj ntawm cov nta, raws li yog cov ntaub ntawv nrog rau cov thawj.

Composing Circuit Court kab zauv, nws yog lam xav hais tias cov zauv tus nqi ntawm lub electromotive quab yuam muaj ib tug zoo kos npe rau thaum tus tau txais kev taw qhia chiv bypass Circuit Court (feem ntau clockwise) coincides nrog nws cov kev taw qhia, thiab tsis zoo yog tias cov lus qhia yog opposite. Tib yam siv rau lub resistor: thaum cov kev taw qhia ntawm tam sim no yog tib yam li hais tias ntawm lub xaiv bypass, lub voltage nco rau nws yog ntaus nqi mus rau "+" kos npe rau. Piv txwv li, E1 - E2 + E3 = I1R1 - I2R2 + I3R3 + I4R4 ...

Raws li ib tug tshwm sim, bypass tag nrho cov ceg teej tug mus rau hauv Circuit Court Cheebtsam ntawm lub system ntawm linear equations, daws hais tias, nws yog ua tau rau kawm tag nrho tam sim no ceg (thiab units). Solved lub kev sib raug zoo tau los ntawm cov qauv ntawm cov voj currents.

Nws yog ib qhov nyuaj rau overestimate qhov tseem ceeb ntawm Kirchhoff kev cai rau hluav taws xob engineering. Yooj Yim ntawm kev sau ntawv sib npaug thiab lawv cov tshuaj los ntawm txoj kev ntawm classical algebra twb yog vim li cas rau lub dav siv.