EMF vs Voltage
Ob qhov hluav taws xob thiab EMF (electromotive force) piav qhia txog hluav taws xob muaj peev xwm sib txawv, tab sis yog cov ntsiab lus sib txawv. Lo lus 'voltage' muaj kev siv ntau, thiab nws zoo ib yam li qhov hluav taws xob muaj peev xwm sib txawv. Tab sis, EMF yog ib lo lus tshwj xeeb thiab siv los piav txog qhov hluav taws xob tsim los ntawm lub roj teeb.
Voltage
Voltage yog lwm lo lus rau hluav taws xob muaj peev xwm sib txawv. Muaj peev xwm sib txawv ntawm point A thiab B tseem hu ua qhov voltage ntawm point A thiab point B. Nws kuj tseem txhais tau tias yog tus nqi ua haujlwm yuav tsum tau ua kom txav ib chav tsev nqi (+ 1 Coulomb) los ntawm B mus rau A. Voltage yog ntsuas hauv Qhov ntsuas hluav taws xob (V). Voltmeter yog cov cuab yeej siv los ntsuas qhov voltage. Lub roj teeb muab qhov hluav taws xob nruab nrab ntawm nws ob qhov kawg (electrodes) thiab nws sab zoo muaj peev xwm ntau dua thiab qhov tsis zoo muaj qhov qis dua.
Nyob hauv ib lub voj voog, tam sim no ntws los ntawm qhov muaj peev xwm siab dua mus rau qis dua. Thaum nws mus los ntawm ib qho resister, qhov voltage ntawm ob kawg tuaj yeem pom. Qhov no yog hu ua 'voltage drop'. Txawm hais tias qhov voltage yog ib txwm hais txog ob lub ntsiab lus qee zaum tib neeg nug txog qhov voltage ntawm ib qho taw tes. Qhov no yog hais txog qhov hluav taws xob ntawm qhov taw tes tshwj xeeb thiab qhov taw qhia siv. Cov ntsiab lus siv no feem ntau yog 'grounded' thiab lub peev xwm ntawm nws suav tias yog 0V.
EMF (ElectroMotive Force)
EMF yog qhov hluav taws xob muab los ntawm lub zog zoo li roj teeb. Sib txawv sib nqus teb kuj tuaj yeem tsim EMF raws li Faraday txoj cai. Txawm hais tias EMF kuj yog qhov hluav taws xob thiab ntsuas hauv Volts (V), nws yog txhua yam hais txog kev tsim hluav taws xob. EMF yog qhov tseem ceeb rau lub tshuab hluav taws xob hluav taws xob los tsav cov hluav taws xob los ntawm lub voj voog. Nws nyiam lub twj tso kua mis.
Thaum lub voj voog hluav taws xob khiav siv EMF, qhov sib npaug ntawm qhov hluav taws xob poob hauv qhov hluav taws xob ntawd sib npaug rau EMF raws li Kirchhoff txoj cai thib ob. Ntxiv rau cov roj teeb, uas siv cov hluav taws xob hluav taws xob, lub hnub ci, roj hlwb thiab cov thermocouples kuj yog cov piv txwv rau EMF generators.
Qhov txawv ntawm Voltage thiab EMF yog dab tsi?
1. EMF yog qhov hluav taws xob tsim los ntawm qhov chaw xws li roj teeb lossis lub tshuab hluav taws xob.
2. Peb tuaj yeem ntsuas qhov voltage ntawm ob lub ntsiab lus, tab sis EMF tsuas muaj nyob nruab nrab ntawm ob qhov kawg ntawm qhov chaw.
3. Voltages nyob rau hauv ib lub voj voog hu ua 'voltage drops' yog nyob rau hauv qhov opposite direction ntawm EMF thiab lawv cov nyiaj yog sib npaug rau EMF raws li Kirchhoff txoj cai thib ob.
