PTC的優異(yi)性能(neng)！

    PTC（Positive Temperature Coeff1Cient）是指在(zai)某(mou)一(yi)溫(wen)(wen)度(du)(du)下電阻(zu)急劇(ju)增加(jia)，具有正溫(wen)(wen)度(du)(du)系數的(de)(de)(de)熱敏(min)電阻(zu)現象或材(cai)料(liao)，可專門用(yong)(yong)作恒(heng)定溫(wen)(wen)度(du)(du)傳感器(qi)。該材(cai)料(liao)是以(yi)BaTiO3或 SrTiO3或PbTiO3為主要(yao)成分的(de)(de)(de)燒結體(ti)(ti)，其(qi)(qi)中(zhong)摻入微(wei)(wei)量的(de)(de)(de)Nb、Ta、Bi、Sb、Y、La等氧化(hua)物進行原(yuan)子價(jia)控制而(er)(er)使之半導(dao)(dao)(dao)化(hua)，常將這種半導(dao)(dao)(dao)體(ti)(ti)化(hua)的(de)(de)(de)BaTiO3等材(cai)料(liao)簡稱為半導(dao)(dao)(dao)（體(ti)(ti)）瓷，同時還添(tian)加(jia)增大(da)其(qi)(qi)正電阻(zu)溫(wen)(wen)度(du)(du)系數的(de)(de)(de)Mn、Fe、Cu、Cr的(de)(de)(de)氧化(hua)物和起其(qi)(qi)他作用(yong)(yong)的(de)(de)(de)添(tian)加(jia)物，采(cai)用(yong)(yong)一(yi)般陶瓷工(gong)藝(yi)成形、高(gao)溫(wen)(wen)燒結而(er)(er)使鈦酸鉑(bo)等及其(qi)(qi)固溶(rong)體(ti)(ti)半導(dao)(dao)(dao)化(hua)，從而(er)(er)得到(dao)正特性(xing)的(de)(de)(de)PTC熱敏(min)電阻(zu)材(cai)料(liao)，其(qi)(qi)溫(wen)(wen)度(du)(du)系數及居里點溫(wen)(wen)度(du)(du)隨組分及燒結條件（尤其(qi)(qi)是冷卻溫(wen)(wen)度(du)(du)）不(bu)同而(er)(er)變化(hua)。

    PTC熱敏(min)電阻(zu)于(yu)(yu)1950年出現(xian)，隨(sui)后(hou)1954年出現(xian)了(le)以鈦酸鋇(bei)為主要材料的(de)(de)PTC熱敏(min)電阻(zu)。PTC熱敏(min)電阻(zu)在工業上(shang)可用(yong)(yong)作溫度的(de)(de)測量(liang)與(yu)控制(zhi)，也用(yong)(yong)于(yu)(yu)汽車某部位(wei)的(de)(de)溫度檢測與(yu)調(diao)節，還大量(liang)用(yong)(yong)于(yu)(yu)民(min)用(yong)(yong)設備，如(ru)控制(zhi)瞬(shun)間開水器(qi)的(de)(de)水溫、空(kong)調(diao)器(qi)與(yu)冷庫的(de)(de)溫度，利用(yong)(yong)本(ben)身加熱作氣體分(fen)析和風速機等方(fang)面(mian)。下面(mian)簡介(jie)一例對加熱器(qi)、馬達、變壓器(qi)、大功率晶體管等電器(qi)的(de)(de)加熱和過(guo)熱保護(hu)方(fang)面(mian)的(de)(de)應用(yong)(yong)。

    PTC熱(re)敏電(dian)(dian)(dian)阻(zu)除(chu)用(yong)作加熱(re)元(yuan)(yuan)(yuan)件(jian)(jian)(jian)外，同時還能起(qi)到“開(kai)關(guan)(guan)”的作用(yong)，兼(jian)有(you)敏感元(yuan)(yuan)(yuan)件(jian)(jian)(jian)、加熱(re)器和開(kai)關(guan)(guan)三種功能，稱(cheng)之(zhi)為“熱(re)敏開(kai)關(guan)(guan)”，電(dian)(dian)(dian)流(liu)通過(guo)元(yuan)(yuan)(yuan)件(jian)(jian)(jian)后引起(qi)溫(wen)(wen)(wen)度(du)(du)升高，即發熱(re)體的溫(wen)(wen)(wen)度(du)(du)上升，當超過(guo)居里點溫(wen)(wen)(wen)度(du)(du)后，電(dian)(dian)(dian)阻(zu)增加，從而限制(zhi)電(dian)(dian)(dian)流(liu)增加，于是電(dian)(dian)(dian)流(liu)的下降導致(zhi)元(yuan)(yuan)(yuan)件(jian)(jian)(jian)溫(wen)(wen)(wen)度(du)(du)降低，電(dian)(dian)(dian)阻(zu)值(zhi)的減小又(you)使(shi)電(dian)(dian)(dian)路電(dian)(dian)(dian)流(liu)增加，元(yuan)(yuan)(yuan)件(jian)(jian)(jian)溫(wen)(wen)(wen)度(du)(du)升高，周而復始，因此具有(you)使(shi)溫(wen)(wen)(wen)度(du)(du)保持在特定范圍的功能，又(you)起(qi)到開(kai)關(guan)(guan)作用(yong)。利用(yong)這種阻(zu)溫(wen)(wen)(wen)特性做(zuo)成加熱(re)源，作為加熱(re)元(yuan)(yuan)(yuan)件(jian)(jian)(jian)應(ying)用(yong)的有(you)暖風器、電(dian)(dian)(dian)烙鐵、烘衣(yi)柜、空調等，還可(ke)對電(dian)(dian)(dian)器起(qi)到過(guo)熱(re)保護作用(yong)。