熱電偶與熱電阻均屬於溫度測量中的接觸式測溫，盡管其作用相同都是測量物體的溫度
，但是他們的原理與特點卻不盡相同。
    首(shou)先(xian)，介(jie)紹(shao)一(yi)下(xia)熱(re)電(dian)偶(ou)
，熱(re)電(dian)偶(ou)是(shi)溫(wen)度(du)測(ce)量(liang)中(zhong)應(ying)用(yong)最(zui)廣(guang)泛(fan)的(de)溫(wen)度(du)器(qi)件(jian)，他(ta)的(de)主(zhu)要(yao)特(te)點(dian)就(jiu)是(shi)測(ce)溫(wen)範(fan)圍(wei)寬(kuan)，性(xing)能(neng)比(bi)較(jiao)穩(wen)定(ding)
，同(tong)時(shi)結(jie)構(gou)簡(jian)單(dan)

，動(dong)態(tai)響(xiang)應(ying)好(hao)，更(geng)能(neng)夠(gou)遠(yuan)傳(chuan)4-20mA電(dian)信(xin)號(hao)，便(bian)於(yu)自(zi)動(dong)控(kong)製(zhi)和(he)集(ji)中(zhong)控(kong)製(zhi)。熱(re)電(dian)偶(ou)的(de)測(ce)溫(wen)原(yuan)理(li)是(shi)基(ji)於(yu)熱(re)電(dian)效(xiao)應(ying)。將(jiang)兩(liang)種(zhong)不(bu)同(tong)的(de)導(dao)體(ti)或(huo)半(ban)導(dao)體(ti)連(lian)接(jie)成(cheng)閉(bi)合(he)回(hui)路(lu)，當(dang)兩(liang)個(ge)接(jie)點(dian)處(chu)的(de)溫(wen)度(du)不(bu)同(tong)時(shi)，回(hui)路(lu)中(zhong)將(jiang)產(chan)生(sheng)熱(re)電(dian)勢(shi)


，這(zhe)種(zhong)現(xian)象(xiang)稱(cheng)為(wei)熱(re)電(dian)效(xiao)應(ying)，又(you)稱(cheng)為(wei)塞(sai)貝(bei)克(ke)效(xiao)應(ying)。閉(bi)合(he)回(hui)路(lu)中(zhong)產(chan)生(sheng)的(de)熱(re)電(dian)勢(shi)有(you)兩(liang)種(zhong)電(dian)勢(shi)組(zu)成(cheng)；溫wen差cha電dian勢shi和he接jie觸chu電dian勢shi。溫wen差cha電dian勢shi是shi指zhi同tong一yi導dao體ti的de兩liang端duan因yin溫wen度du不bu同tong而er產chan生sheng的de電dian勢shi，不bu同tong的de導dao體ti具ju有you不bu同tong的de電dian子zi密mi度du，所suo以yi他ta們men產chan生sheng的de電dian勢shi也ye不bu相xiang同tong


，而er接jie觸chu電dian勢shi顧gu名ming思si義yi就jiu是shi指zhi兩liang種zhong不bu同tong的de導dao體ti相xiang接jie觸chu時shi
，因yin為wei他ta們men的de電dian子zi密mi度du不bu同tong所suo以yi產chan生sheng一yi定ding的de電dian子zi擴kuo散san，當dang他ta們men達da到dao一yi定ding的de平ping衡heng後hou所suo形xing成cheng的de電dian勢shi，接jie觸chu電dian勢shi的de大da小xiao取qu決jue於yu兩liang種zhong不bu同tong導dao體ti的de材cai料liao性xing質zhi以yi及ji他ta們men接jie觸chu點dian的de溫wen度du。目mu前qian國guo際ji上shang應ying用yong的de熱re電dian偶ou具ju有you一yi個ge標biao準zhun規gui範fan，國guo際ji上shang規gui定ding熱re電dian偶ou分fen為wei八ba個ge不bu同tong的de分fen度du，分fen別bie為weiB
，R，S
，K
，N，E，J和T
，其測量溫度的最低可測零下270攝氏度，最高可達1800攝氏度，其中B，R，S屬於鉑係列的熱電偶，由於鉑屬於貴重金屬
，所以他們又被稱為貴金屬熱電偶而er剩sheng下xia的de幾ji個ge則ze稱cheng為wei廉lian價jia金jin屬shu熱re電dian偶ou。熱re電dian偶ou的de結jie構gou有you兩liang種zhong，普pu通tong型xing和he鎧kai裝zhuang型xing。普pu通tong性xing熱re電dian偶ou一yi般ban由you熱re電dian極ji
，絕jue緣yuan管guan，保bao護hu套tao管guan和he接jie線xian盒he等deng部bu分fen組zu成cheng
，而er鎧裝型熱電偶zeshijiangredianousi，jueyuancailiaohejinshubaohutaoguansanzhezuhezhuangpeihou
，jingguolashenjiagongerchengdeyizhongjianshidezuheti。danshiredianoudedianxinhaoquexuyaoyizhongteshudedaoxianlaijinxingchuandi
，zhezhongdaoxianwomenchengweibuchangdaoxian。butongderedianouxuyaobutongdebuchangdaoxian
，qizhuyaozuoyongjiushiyuredianoulianjie，shiredianoudecanbiduanyuanlidianyuan，congershicanbiduanwenduwending。buchangdaoxianyoufenweibuchangxingheyanchangxingliangzhong，yanchangdaoxiandehuaxuechengfenyubeibuchangderedianouxiangtong

，danshishijizhong，yanchangxingdedaoxianyebingbushiyongheredianouxiangtongcaizhidejinshu，yibancaiyongheredianoujuyouxiangtongdianzimidudedaoxiandaiti。buchangdaoxiandeyuredianoudelianxianyibandoushihenmingle，redianoudezhengjilianjiebuchangdaoxiandehongsexian，erfujizelianjieshengxiadeyanse。yibandebuchangdaoxiandecaizhidabufendoucaiyongtongniehejin。
　　其qi次ci我wo們men介jie紹shao一yi下xia熱re電dian阻zu，熱re電dian阻zu雖sui然ran在zai工gong業ye中zhong應ying用yong也ye比bi較jiao廣guang泛fan，但dan是shi由you於yu他ta的de測ce溫wen範fan圍wei使shi他ta的de應ying用yong受shou到dao了le一yi定ding的de限xian製zhi，熱re電dian阻zu的de測ce溫wen原yuan理li是shi基ji於yu導dao體ti或huo半ban導dao體ti的de電dian阻zu值zhi隨sui著zhe溫wen度du的de變bian化hua而er變bian化hua的de特te性xing。其qi優you點dian也ye很hen多duo，也ye可ke以yi遠yuan傳chuan電dian信xin號hao，靈ling敏min度du高gao
，穩wen定ding性xing強qiang，互hu換huan性xing以yi及ji準zhun確que性xing都dou比bi較jiao好hao，但dan是shi需xu要yao電dian源yuan激ji勵li，不bu能neng夠gou瞬shun時shi測ce量liang溫wen度du的de變bian化hua。工gong業ye用yong熱re電dian阻zu一yi般ban采cai用yongPt100,Pt10,Cu50,Cu100,鉑熱電阻的測溫的範圍一般為零下200-800攝氏度，銅熱電阻為零下40到140攝氏度。熱電阻和熱電偶一樣的區分類型，但是他卻不需要補償導線，而且比熱點偶便宜。