壓力(li)變送器(qi)也稱差變送器(qi)，主要由(you)測(ce)壓元件傳(chuan)感(gan)器(qi)、模塊電(dian)路、顯示表頭、表殼(ke)和過(guo)程連接件等組成(cheng)。它能將接收(shou)的氣體、液體等壓力(li)信號轉變成(cheng)標準的電(dian)流電(dian)壓信號，以供給(gei)指(zhi)(zhi)示報警儀、記(ji)錄(lu)儀、調(diao)節器(qi)等二(er)次儀表進行(xing)測(ce)量、指(zhi)(zhi)示和過(guo)程調(diao)節。

壓(ya)(ya)(ya)(ya)力(li)(li)(li)變(bian)送器測量原理(li)是：流程壓(ya)(ya)(ya)(ya)力(li)(li)(li)和參(can)考壓(ya)(ya)(ya)(ya)力(li)(li)(li)分別作用于(yu)集成(cheng)(cheng)硅壓(ya)(ya)(ya)(ya)力(li)(li)(li)敏感元件(jian)的(de)(de)兩端，其差壓(ya)(ya)(ya)(ya)使硅片(pian)變(bian)形（位移(yi)很小，僅μm級），以使硅片(pian)上用半導(dao)體技術制成(cheng)(cheng)的(de)(de)全動態惠斯登電(dian)(dian)(dian)橋在外(wai)部電(dian)(dian)(dian)流源驅動下(xia)輸(shu)(shu)(shu)出正(zheng)比于(yu)壓(ya)(ya)(ya)(ya)力(li)(li)(li)的(de)(de)mV級電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)信(xin)號(hao)。由(you)于(yu)硅材料的(de)(de)強性，所以輸(shu)(shu)(shu)出信(xin)號(hao)的(de)(de)線(xian)(xian)性度及變(bian)差指標(biao)均(jun)很高(gao)。工作時(shi)，壓(ya)(ya)(ya)(ya)力(li)(li)(li)變(bian)送器將被(bei)測物理(li)量轉(zhuan)換(huan)(huan)成(cheng)(cheng)mV級的(de)(de)電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)信(xin)號(hao)，并送往放(fang)大(da)倍數很高(gao)而又(you)可以互相抵消(xiao)溫度漂移(yi)的(de)(de)差動式放(fang)大(da)器。放(fang)大(da)后的(de)(de)信(xin)號(hao)經(jing)電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)電(dian)(dian)(dian)流轉(zhuan)換(huan)(huan)變(bian)換(huan)(huan)成(cheng)(cheng)相應的(de)(de)電(dian)(dian)(dian)流信(xin)號(hao)，再經(jing)過(guo)非線(xian)(xian)性校(xiao)正(zheng)，zui后產生與輸(shu)(shu)(shu)入壓(ya)(ya)(ya)(ya)力(li)(li)(li)成(cheng)(cheng)線(xian)(xian)性對應關系(xi)的(de)(de)標(biao)準電(dian)(dian)(dian)流電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)信(xin)號(hao)。

壓(ya)力變(bian)(bian)送(song)器根據測壓(ya)范圍可分成(cheng)一般(ban)壓(ya)力變(bian)(bian)送(song)器（0.001MPa～20MP3）和微(wei)差壓(ya)變(bian)(bian)送(song)器（0～30kPa）兩種。