sc補償導線作用的實質是(shi)熱電偶的延長
熱(re)(re)電偶(ou)的(de)sc補(bu)償導線是在(zai)一(yi)定溫度范圍內(nei)（包括常溫0）具有(you)與所匹配熱(re)(re)電偶(ou)熱(re)(re)電動勢(shi)相(xiang)(xiang)同標稱值的(de)一(yi)對帶有(you)絕緣層的(de)導線，用他們(men)連接熱(re)(re)電偶(ou)與測(ce)量裝置(zhi)，相(xiang)(xiang)當(dang)于將熱(re)(re)電偶(ou)延長到測(ce)量裝置(zhi)。
由于”熱(re)(re)(re)(re)電(dian)(dian)(dian)偶(ou)的(de)補(bu)償導(dao)(dao)(dao)(dao)線(xian)(xian)是在(zai)一(yi)定溫(wen)度范(fan)圍(wei)內(nei)（包括(kuo)常溫(wen)0）具有(you)(you)與所匹配(pei)熱(re)(re)(re)(re)電(dian)(dian)(dian)偶(ou)熱(re)(re)(re)(re)電(dian)(dian)(dian)動勢(shi)相(xiang)同(tong)(tong)(tong)標稱值的(de)一(yi)對(dui)帶(dai)有(you)(you)絕緣層的(de)導(dao)(dao)(dao)(dao)線(xian)(xian)“，它是可(ke)以(yi)在(zai)一(yi)定范(fan)圍(wei)內(nei)構成(cheng)熱(re)(re)(re)(re)電(dian)(dian)(dian)偶(ou)（實際上(shang)補(bu)償型的(de)補(bu)償導(dao)(dao)(dao)(dao)線(xian)(xian)和同(tong)(tong)(tong)分度熱(re)(re)(re)(re)電(dian)(dian)(dian)偶(ou)是同(tong)(tong)(tong)材質的(de)），根據熱(re)(re)(re)(re)電(dian)(dian)(dian)偶(ou)的(de)中(zhong)(zhong)間(jian)(jian)導(dao)(dao)(dao)(dao)體(ti)定律“在(zai)熱(re)(re)(re)(re)電(dian)(dian)(dian)偶(ou)回路中(zhong)(zhong)接入中(zhong)(zhong)間(jian)(jian)導(dao)(dao)(dao)(dao)體(ti)（第(di)三導(dao)(dao)(dao)(dao)體(ti)）只(zhi)要中(zhong)(zhong)間(jian)(jian)導(dao)(dao)(dao)(dao)體(ti)兩端溫(wen)度相(xiang)同(tong)(tong)(tong)，中(zhong)(zhong)間(jian)(jian)導(dao)(dao)(dao)(dao)體(ti)的(de)引(yin)入對(dui)熱(re)(re)(re)(re)電(dian)(dian)(dian)偶(ou)回路總電(dian)(dian)(dian)勢(shi)沒(mei)有(you)(you)影響。也(ye)就是說在(zai)不計熱(re)(re)(re)(re)電(dian)(dian)(dian)偶(ou)的(de)影響時，補(bu)償導(dao)(dao)(dao)(dao)線(xian)(xian)也(ye)可(ke)以(yi)產(chan)生熱(re)(re)(re)(re)電(dian)(dian)(dian)勢(shi)，其大小等于熱(re)(re)(re)(re)電(dian)(dian)(dian)偶(ou)尾(wei)端與測量裝置之(zhi)間(jian)(jian)的(de)溫(wen)差電(dian)(dian)(dian)勢(shi)。
正確使用時，熱(re)電(dian)偶(ou)的(de)電(dian)勢(shi)和補(bu)償導線電(dian)勢(shi)疊加(jia)，在冷熱(re)端溫度不變(bian)的(de)情(qing)況下，隨著熱(re)電(dian)偶(ou)與補(bu)償導線連接(jie)處的(de)溫度變(bian)化(hua)，熱(re)電(dian)偶(ou)的(de)溫差(cha)電(dian)勢(shi)增大補(bu)償導線的(de)溫差(cha)電(dian)勢(shi)減小，反(fan)之亦然，達到補(bu)償熱(re)電(dian)偶(ou)與測量裝(zhuang)置(zhi)之間的(de)溫度變(bian)化(hua)所產(chan)生(sheng)的(de)影(ying)響(xiang)。 測量裝(zhuang)置(zhi)測到的(de)是熱(re)電(dian)偶(ou)產(chan)生(sheng)的(de)熱(re)電(dian)勢(shi)與補(bu)償導線產(chan)生(sheng)的(de)補(bu)償電(dian)勢(shi)的(de)疊加(jia)電(dian)勢(shi)。
