熱電阻在工業(ye)生(sheng)產過程中很常見，本文分(fen)享熱(re)電(dian)阻(zu)工作原理、熱(re)電(dian)阻(zu)結(jie)構和熱(re)電(dian)阻(zu)基本特性，對大家了(le)解熱(re)電(dian)阻(zu)和選購高(gao)性能熱(re)電(dian)阻(zu)很有幫助。
熱電阻工作原理及結構
熱電(dian)阻是(shi)(shi)利(li)用物質在溫(wen)(wen)度(du)變(bian)(bian)化時(shi)自身電(dian)阻也(ye)隨著發生變(bian)(bian)化的(de)(de)特性(xing)來測(ce)量溫(wen)(wen)度(du)的(de)(de).熱電(dian)阻的(de)(de)感(gan)溫(wen)(wen)元件是(shi)(shi)用細金屬絲(si)均勾地雙(shuang)繞在絕緣材料(liao)做的(de)(de)骨(gu)架上(shang)，當(dang)被測(ce)介(jie)質中(zhong)有(you)溫(wen)(wen)度(du)梯度(du)存在時(shi)，所測(ce)得的(de)(de)溫(wen)(wen)度(du)是(shi)(shi)感(gan)溫(wen)(wen)元件所在范圍內介(jie)質層中(zhong)的(de)(de)平均溫(wen)(wen)度(du)。
裝(zhuang)(zhuang)配(pei)式熱電阻主要(yao)由接(jie)線(xian)盒，接(jie)線(xian)端子，保護套管，絕緣套管，感溫(wen)元件組(zu)成，基本形式如圖1所示。在實際應用中大多還配(pei)有各種安裝(zhuang)(zhuang)固定裝(zhuang)(zhuang)置，以滿足生產現場的安裝(zhuang)(zhuang)。
裝(zhuang)配(pei)式(shi)熱(re)電阻結(jie)構示意圖：①出線孔密封(feng)圈(quan) ②出線孔螺母 ③鏈條 ④蓋子 ⑤接(jie)(jie)線柱 ⑥蓋子的(de)密封(feng)圈(quan) ⑦接(jie)(jie)線盒 ⑧接(jie)(jie)線座 ⑨熱(re)電阻保護管 ⑩絕(jue)緣管 ?熱(re)電阻元件
鎧(kai)裝(zhuang)(zhuang)熱(re)電(dian)阻比裝(zhuang)(zhuang)配(pei)式(shi)熱(re)電(dian)阻直徑小，具有易(yi)彎(wan)曲(qu)，抗沖擊振(zhen)動，堅固耐用等特點，還(huan)可以作為(wei)裝(zhuang)(zhuang)配(pei)式(shi)熱(re)電(dian)阻的內(nei)芯元件使(shi)用，外(wai)保護套(tao)采(cai)用不(bu)銹鋼內(nei)充滿高密度氧化物質絕緣(yuan)體,適合(he)安裝(zhuang)(zhuang)在環境惡劣的場合(he)，測溫范圍為(wei)-200~500C。使(shi)用中應注意其端部是感(gan)溫元件的位(wei)置(zhi)，其端部30mm不(bu)能彎(wan)曲(qu)，以免損傷(shang)感(gan)溫元件。
熱(re)電(dian)(dian)(dian)(dian)阻(zu)感溫(wen)(wen)元(yuan)(yuan)(yuan)(yuan)件(jian)早期的(de)(de)產品大多(duo)為(wei)骨(gu)架繞線(xian)式(shi)的(de)(de)，有(you)云母骨(gu)架，塑料骨(gu)架，玻璃骨(gu)架、陶瓷骨(gu)架和抗震(zhen)式(shi)外繞整體燒(shao)結鉑(bo)(bo)電(dian)(dian)(dian)(dian)阻(zu)幾種(zhong)，這些(xie)鉑(bo)(bo)電(dian)(dian)(dian)(dian)阻(zu)感溫(wen)(wen)元(yuan)(yuan)(yuan)(yuan)件(jian)中高性能(neng)高性價(jia)比和長使(shi)用(yong)(yong)壽命的(de)(de)是(shi)抗震(zhen)式(shi)外繞整體燒(shao)結鉑(bo)(bo)電(dian)(dian)(dian)(dian)阻(zu)元(yuan)(yuan)(yuan)(yuan)件(jian)，因其價(jia)格(ge)在這些(xie)元(yuan)(yuan)(yuan)(yuan)件(jian)中貴，國內只有(you)生產優質鉑(bo)(bo)電(dian)(dian)(dian)(dian)阻(zu)的(de)(de)廠家才在使(shi)用(yong)(yong)。薄(bo)膜熱(re)電(dian)(dian)(dian)(dian)阻(zu)元(yuan)(yuan)(yuan)(yuan)件(jian)已得到(dao)廣泛應(ying)用(yong)(yong)，如圖2所示(shi)，既可用(yong)(yong)于(yu)裝配式(shi)熱(re)電(dian)(dian)(dian)(dian)阻(zu)，也可用(yong)(yong)于(yu)鎧裝式(shi)熱(re)電(dian)(dian)(dian)(dian)阻(zu)，結構小巧，價(jia)格(ge)低，但薄(bo)膜熱(re)電(dian)(dian)(dian)(dian)阻(zu)元(yuan)(yuan)(yuan)(yuan)件(jian)的(de)(de)測試電(dian)(dian)(dian)(dian)流較小，通常為(wei)1mA，大不超過3mA。感溫(wen)(wen)元(yuan)(yuan)(yuan)(yuan)件(jian)斷路(lu)(lu)和短路(lu)(lu)，云母骨(gu)架，塑料骨(gu)架結構的(de)(de)可以嘗試修復，其他結構的(de)(de)感溫(wen)(wen)元(yuan)(yuan)(yuan)(yuan)件(jian)無法修復只能(neng)更換。
常用熱電阻基本特性
常用熱(re)電(dian)阻的基本特性如(ru)下(xia)表所示：
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