Yuav ua li cas txiav txim qhov zoo thiab lub neej ncua ntawm pH meter electrode
Feem ntau, kev tshawb nrhiav electrode ntawm pH meter feem ntau txiav txim siab qhov zoo ntawm cov electrode los ntawm txoj kab nqes ntawm electrode, thiab tseem tuaj yeem txiav txim los ntawm xoom muaj peev xwm mV tus nqi ntawm cov electrode. Rau electrodes nyob rau hauv industrial zaus, lub Hoobkas qauv yog ib tug nqes hav ntawm 95 mus rau 105 feem pua. Zero peev xwm: ± 15mV, xoom muaj peev xwm yog qhov ntau, nyob rau hauv qhov no yog cov electrodes zoo heev, tsis yog 8.2mV muab los ntawm qee cov tuam txhab 'meter', txwv zero peev xwm ntawm electrodes mus txog 8.2mV. Tom qab siv rau ib lub sijhawm, lub peev xwm xoom yuav hloov, thiab nws raug tso cai hauv ± 60mV. Tab sis txoj kab nqes yuav tsum tsis txhob qis dua 70 feem pua, yog tias xav tau, nws yuav tsum tsis txhob qis dua 80 feem pua.
The pH measurement adopts the potential analysis method, the so-called potential analysis method, that is, the electrode potential of the electrochemical cell is measured by the zero current method. The main feature of the pH electrode is high internal resistance, generally tens of megohms to hundreds of megohms. Therefore it requires the pH meter to have very high input impedance. The input impedance of a general pH meter should be at least 1000 times the internal resistance of the electrode. Therefore, the input impedance of the pH meter should be >5 × 1011Ω mus rau 1 × 1012Ω, tab sis vim hais tias cov iav sab hauv tsis yog qhov tas li, nws yog qhov ntsuas kub ntawm qhov ntsuas kub. Piv txwv li, ib qho hluav taws xob muaj qhov ua haujlwm sab hauv ntawm 100 megohms ntawm 28 degree, thiab 800 megohms ntawm 7 degree, thiab 1600 megohms ntawm 0 degree.
Yog li ntawd, yog hais tias lub input impedance ntawm lub pH meter tsis siab txaus, qhov tso tawm tus nqi yuav drift thiab ua tsis ruaj khov. Nyob rau tib lub sij hawm, ib tug tam sim no yuav raug generated nyob rau hauv lub ntsuas Circuit Court, uas yuav polarize lub electrode thiab rhuav tshem cov siv electrode. Yog li ntawd, thaum tsim lub pH meter, qhov input impedance yuav tsum ncav cuag 1012Ω lossis ntau dua, tab sis qhov no tsis txaus. Hauv kev siv tswv yim, cov tswv yim impedance ntawm qee cov twj paj nruag Lub sealing ntawm ib feem tsis zoo, los yog nws muab tso rau hauv ib qho chaw muaj dej noo. Tom qab ib lub sij hawm, lub input impedance yuav tsis tau raws li qhov yuav tsum tau ntawm 1012Ω los yog ntau tshaj, thiab qhov teeb meem no yog recessive. Thaum tus nqi tso tawm feem ntau tsis raug, Ua ntej ntawm tag nrho, nws tau xav tias cov electrode yog qhov teeb meem. Qhov no yog tiag tiag txhaum rau lub electrode!
Hais txog lub neej ntawm lub electrode ntawm lub ph meter, lub teb chaws tus qauv yog "lub sij hawm lav ntawm lub electrode, pib txij li hnub ntawm kev tsim khoom cim nyob rau hauv lub electrode, thaum nws yog unpacked thiab siv nyob rau hauv ib lub xyoo ntawm kev siv, cov chaw tsim tshuaj paus yuav tsum. lub luag haujlwm kho lossis rov qab los. " Yog li ntawd, qhov kev ruaj ntseg zoo ntawm electrode Lub sij hawm yog raws li lub hauv paus ntsiab lus uas nws tsis tau siv, thiab lub sij hawm yog ib xyoos. Feem ntau hais lus, lub neej ntawm electrode yog ib xyoos, uas tsis yog lawm. Lub neej kev pab cuam ntawm lub electrode muaj ntau yam ua rau nruab nrab siv, thiab kev pab cuam lub neej ntawm cov xov xwm sib txawv yog txawv kiag li. Hauv ntau qhov mob hnyav, nws tsuas yog siv tau 2 lub hlis xwb. Thiab qee qhov kev tshaj tawm zoo dua tuaj yeem siv tau li ib xyoos lossis ntev dua.
