了解一下體積表面電阻率測試儀的運行原理
量(liang)限從(cong)1×104Ω ～1×1018 Ω，是目前國內(nei)測(ce)(ce)量(liang)范圍zui寬，準確度zui高(gao)的(de)數字(zi)超高(gao)阻測(ce)(ce)量(liang)儀。
電流測(ce)量范圍為2×10-4 ～1×10-16A。機(ji)內(nei)測(ce)試(shi)電壓為10/50/100/250/500/1000V任意(yi)可調。
體積表面電阻率測試儀具(ju)有精度高、顯(xian)示迅速、性好穩定、讀數方便， 適用(yong)于防靜電(dian)(dian)產品(pin)如防靜電(dian)(dian)鞋、防靜電(dian)(dian)塑料(liao)橡膠制品(pin)、計算機房防靜電(dian)(dian)活動(dong)地板等電(dian)(dian)阻(zu)值的(de)檢驗以(yi)及絕緣(yuan)材料(liao)和電(dian)(dian)子電(dian)(dian)器(qi)產品(pin)的(de)絕緣(yuan)電(dian)(dian)阻(zu)測量。本儀器(qi)除能測電(dian)(dian)阻(zu)外(wai)，還能直接(jie)測量微弱電(dian)(dian)流。
根(gen)據歐姆(mu)定律，被測(ce)(ce)電(dian)阻Rx等于施加電(dian)壓(ya)V除以通過的(de)電(dian)流I。傳統的(de)高阻計的(de)工作原理是測(ce)(ce)量電(dian)壓(ya)V固(gu)定，通過測(ce)(ce)量流過取(qu)樣電(dian)阻的(de)電(dian)流I來得到(dao)電(dian)阻值。
從歐(ou)姆定律可以看出，由于電(dian)(dian)流I是(shi)與電(dian)(dian)阻成(cheng)反比(bi)，而不(bu)是(shi)成(cheng)正(zheng)比(bi)，所以電(dian)(dian)阻的(de)顯示值是(shi)非(fei)線(xian)性(xing)的(de)，即(ji)電(dian)(dian)阻無窮(qiong)大時，電(dian)(dian)流為零(ling)，即(ji)表頭的(de)零(ling)位處是(shi)∞，其附(fu)近的(de)刻(ke)度(du)非(fei)常密(mi)，分(fen)辨率很低。整個刻(ke)度(du)是(shi)非(fei)線(xian)性(xing)的(de)。又由于測量不(bu)同(tong)的(de)電(dian)(dian)阻時，其電(dian)(dian)壓V也會(hui)有些變(bian)化，所以普通的(de)高阻計是(shi)精度(du)差、分(fen)辨率低。
體積表面電阻率測試儀是(shi)同(tong)時測(ce)出電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)兩(liang)端的電(dian)(dian)(dian)(dian)壓(ya)V和(he)流(liu)(liu)過(guo)(guo)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)的電(dian)(dian)(dian)(dian)流(liu)(liu)I，通(tong)過(guo)(guo)內部的大規模(mo)集(ji)成電(dian)(dian)(dian)(dian)路完成電(dian)(dian)(dian)(dian)壓(ya)除以(yi)電(dian)(dian)(dian)(dian)流(liu)(liu)的計(ji)算，然(ran)后把所得到(dao)(dao)的結果經過(guo)(guo)A/D轉(zhuan)換后以(yi)數(shu)字(zi)顯(xian)(xian)示出電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)值，即便是(shi)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)兩(liang)端的電(dian)(dian)(dian)(dian)壓(ya)V和(he)流(liu)(liu)過(guo)(guo)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)的電(dian)(dian)(dian)(dian)流(liu)(liu)I是(shi)同(tong)時變(bian)(bian)化(hua)(hua)，其顯(xian)(xian)示的電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)值不象(xiang)普通(tong)高阻(zu)(zu)(zu)計(ji)那樣因(yin)被測(ce)電(dian)(dian)(dian)(dian)壓(ya)V的變(bian)(bian)化(hua)(hua)或(huo)電(dian)(dian)(dian)(dian)流(liu)(liu)I的變(bian)(bian)化(hua)(hua)而(er)變(bian)(bian)，所以(yi)，即使測(ce)量(liang)電(dian)(dian)(dian)(dian)壓(ya)、被測(ce)量(liang)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)、電(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)壓(ya)等發生(sheng)變(bian)(bian)化(hua)(hua)對其結果影響不大，其測(ce)量(liang)精度很高，從(cong)理論(lun)上講其誤差可以(yi)做到(dao)(dao)零，而(er)實際(ji)誤差可以(yi)做到(dao)(dao)千分(fen)之(zhi)幾(ji)或(huo)萬分(fen)之(zhi)幾(ji)。
