傳感器是能夠受規定的被測量並按照一定的規律轉換成可用輸出信號的器件或裝置的總稱,通常由敏感元件和轉換元件組成。當傳感器的輸出為規定的標準信號時
，則稱為變送器。 

　　變(bian)送(song)器(qi)的(de)概(gai)念(nian)是(shi)將(jiang)非(fei)標(biao)準(zhun)電(dian)信(xin)號(hao)轉(zhuan)換(huan)為(wei)標(biao)準(zhun)電(dian)信(xin)號(hao)的(de)儀(yi)器(qi)，傳(chuan)感(gan)器(qi)則(ze)是(shi)將(jiang)物(wu)理(li)信(xin)號(hao)轉(zhuan)換(huan)為(wei)電(dian)信(xin)號(hao)的(de)器(qi)件(jian)，過(guo)去(qu)常(chang)講(jiang)物(wu)理(li)信(xin)號(hao)，現(xian)在(zai)其(qi)他(ta)信(xin)號(hao)也(ye)有(you)了(le)。一(yi)次(ci)儀(yi)表(biao)指(zhi)現(xian)場(chang)測(ce)量(liang)儀(yi)表(biao)或(huo)基(ji)地(di)控(kong)製(zhi)表(biao)
，二(er)次(ci)儀(yi)表(biao)指(zhi)利(li)用(yong)一(yi)次(ci)表(biao)信(xin)號(hao)完(wan)成(cheng)其(qi)他(ta)功(gong)能(neng)：諸如控製，顯示等功能的儀表。

　　傳感器和變送器本是熱工儀表的概念。傳感器是把非電物理量如溫度、壓力、液位、物料、氣體特性等轉換成電信號或把物理量如壓力
、yeweidengzhijiesongdaobiansongqi。biansongqizeshibachuanganqicaijidaodeweiruodedianxinhaofangdayibianzhuansonghuoqidongkongzhiyuanjian。huojiangchuanganqishurudefeidianliangzhuanhuanchengdianxinhaotongshifangdayibiangongyuanfangcelianghekongzhidexinhaoyuan。genjuxuyaohaikejiangmoniliangbianhuanweishuziliang。chuanganqihebiansongqiyitonggouchengzidongkongzhidejiancexinhaoyuan。butongdewuliliangxuyaobutongdechuanganqihexiangyingdebiansongqi。haiyouyizhongbiansongqibushijiangwuliliangbianhuanchengdianxinhao，ruyizhongguolushuiweijide“差壓變送器”，他(ta)是(shi)將(jiang)液(ye)位(wei)傳(chuan)感(gan)器(qi)裏(li)的(de)下(xia)部(bu)的(de)水(shui)和(he)上(shang)部(bu)蒸(zheng)汽(qi)的(de)冷(leng)凝(ning)水(shui)通(tong)過(guo)儀(yi)表(biao)管(guan)送(song)到(dao)變(bian)送(song)器(qi)的(de)波(bo)紋(wen)管(guan)兩(liang)側(ce)
，以(yi)波(bo)紋(wen)管(guan)兩(liang)側(ce)的(de)差(cha)壓(ya)帶(dai)動(dong)機(ji)械(xie)放(fang)大(da)裝(zhuang)置(zhi)用(yong)指(zhi)針(zhen)指(zhi)示(shi)水(shui)位(wei)的(de)一(yi)種(zhong)遠(yuan)方(fang)儀(yi)表(biao)。當(dang)然(ran)還(hai)有(you)把(ba)電(dian)氣(qi)模(mo)擬(ni)量(liang)變(bian)換(huan)成(cheng)數(shu)字(zi)量(liang)的(de)也(ye)可(ke)以(yi)叫(jiao)變(bian)送(song)器(qi)。以(yi)上(shang)隻(zhi)是(shi)從(cong)概(gai)念(nian)上(shang)說(shuo)明(ming)傳(chuan)感(gan)器(qi)和(he)變(bian)送(song)器(qi)的(de)區(qu)別(bie)。