樣(yang)品中的(de)(de)被測組(zu)份(fen)(fen)在裂(lie)解管中反應(ying)轉化(hua)為可滴(di)(di)定(ding)(ding)組(zu)份(fen)(fen)，由載(zai)氣(qi)帶入(ru)滴(di)(di)定(ding)(ding)池(chi)與滴(di)(di)定(ding)(ding)劑(ji)發生(sheng)反應(ying)，使滴(di)(di)定(ding)(ding)劑(ji)濃(nong)度(du)發生(sheng)變(bian)(bian)(bian)化(hua)。測量電(dian)(dian)(dian)極對(dui)(dui)這(zhe)一變(bian)(bian)(bian)化(hua)產生(sheng)相應(ying)的(de)(de)電(dian)(dian)(dian)位響應(ying)，從而使參考(kao)━測量電(dian)(dian)(dian)極對(dui)(dui)的(de)(de)電(dian)(dian)(dian)位發生(sheng)相應(ying)的(de)(de)變(bian)(bian)(bian)化(hua)，使這(zhe)一電(dian)(dian)(dian)位值(zhi)不再等于(yu)儀(yi)器(qi)(qi)設定(ding)(ding)的(de)(de)給定(ding)(ding)偏壓(ya)值(zhi)，兩者的(de)(de)差值(zhi)即為庫(ku)侖(lun)放(fang)(fang)大器(qi)(qi)的(de)(de)輸(shu)入(ru)信號，經放(fang)(fang)大器(qi)(qi)放(fang)(fang)大后，輸(shu)出(chu)(chu)相應(ying)的(de)(de)電(dian)(dian)(dian)壓(ya)加(jia)到電(dian)(dian)(dian)解池(chi)電(dian)(dian)(dian)解電(dian)(dian)(dian)極對(dui)(dui)上，在陽極電(dian)(dian)(dian)生(sheng)滴(di)(di)定(ding)(ding)劑(ji)以補充被消(xiao)耗(hao)的(de)(de)滴(di)(di)定(ding)(ding)劑(ji)，直至(zhi)滴(di)(di)定(ding)(ding)劑(ji)濃(nong)度(du)恢復到平衡狀態時(shi)的(de)(de)濃(nong)度(du)。儀(yi)器(qi)(qi)測量出(chu)(chu)電(dian)(dian)(dian)解過程中消(xiao)耗(hao)的(de)(de)電(dian)(dian)(dian)量，根(gen)據(ju)法(fa)拉(la)第電(dian)(dian)(dian)解定(ding)(ding)律計算出(chu)(chu)被測組(zu)份(fen)(fen)的(de)(de)含(han)量。

  法拉第定(ding)律(lv)概述:

電解時，電極上析出或溶入的物質量和通過電解池的電量成正比；每通過96500庫侖的電量，在電極上即析出或溶入1克當量的任何物質。

                         Q         M

                  W = ─────×──

                       96500          n

                 W─析出的物質質量，以克計     n─電極反應的電子轉移數

M─待測物質的分子或原子量    Q─電量，以庫侖計

    法拉(la)第定律是庫侖分析的(de)基(ji)礎(chu)，此公(gong)式是庫侖分析中的(de)基(ji)本方程，所有的(de)庫侖分析都根據這(zhe)個方程式來進(jin)行計(ji)算。