一、電導率儀的電極常數
電(dian)(dian)導率儀的電(dian)(dian)極(ji)常數是指電(dian)(dian)導電(dian)(dian)極(ji)的長(chang)度與面積(ji)之間的比值,這個比值影響(xiang)電(dian)(dian)極(ji)的靈敏(min)度。電(dian)(dian)極(ji)常數越小,意味著電(dian)(dian)極(ji)面積(ji)越大,從而(er)使得電(dian)(dian)極(ji)的靈敏(min)度更高。
電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)常(chang)數可(ke)以(yi)通過公式K=1/(σ*A/D)計算得出,其中(zhong)(zhong)K是電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)常(chang)數(單(dan)位(wei):S/cm),σ是介質的(de)(de)電(dian)(dian)(dian)導(dao)率(單(dan)位(wei):S/cm),A是電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)面積(單(dan)位(wei):cm2),D是電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)間(jian)距(單(dan)位(wei):cm)。此外(wai),電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)常(chang)數也可(ke)以(yi)通過在(zai)特定(ding)濃度的(de)(de)KCL溶液中(zhong)(zhong)測(ce)量電(dian)(dian)(dian)導(dao)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)的(de)(de)電(dian)(dian)(dian)導(dao)來測(ce)定(ding),此時KCL溶液的(de)(de)電(dian)(dian)(dian)導(dao)率是已(yi)知的(de)(de)。
常(chang)見的電(dian)(dian)導電(dian)(dian)極常(chang)數(shu)(shu)有0.01、0.1、1.0、10四種類(lei)型(xing),具體(ti)值通常(chang)標記(ji)在電(dian)(dian)導電(dian)(dian)極上,用戶(hu)可以根據電(dian)(dian)極上標注的常(chang)數(shu)(shu)來調(diao)節(jie)儀器面(mian)板上的“常(chang)數(shu)(shu)”補(bu)償調(diao)節(jie)旋鈕(niu),以確保測量結(jie)果的準確性。
二、電導率儀的單位介紹
電導率儀的單位通常(chang)是西(xi)門(men)子/米(S/m)。
西門子(zi)/米是電阻(zu)率(ρ)的(de)倒(dao)數,其中(zhong)σ=1/ρ。換句(ju)話說(shuo),當(dang)1安培(1A)的(de)電流通過物體的(de)橫截面(mian),并在存在1伏(fu)(fu)特(te)(1V)的(de)電壓時,該物體的(de)電導就是1S。西門子(zi)實際(ji)上(shang)等(deng)效于1安培/伏(fu)(fu)特(te)。
在實(shi)際應用中,也常用毫西(xi)(xi)門(men)子(mS/m)和微西(xi)(xi)門(men)子(μS/cm)作為(wei)單(dan)位。例(li)如,1μS/cm=0.001mS/m;1000μS/cm=1mS/m。這些單(dan)位的使用取決于具體的測量需求和被測物(wu)質的類(lei)型。