變壓器（Transformer）是(shi)利用(yong)電(dian)(dian)磁感應(ying)的(de)(de)原(yuan)理來改變(bian)(bian)(bian)交(jiao)流電(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)的(de)(de)裝置，主要(yao)構件(jian)是(shi)初級(ji)(ji)線圈(quan)、次級(ji)(ji)線圈(quan)和鐵芯(xin)（磁芯(xin)）。主要(yao)功(gong)能有：電(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)變(bian)(bian)(bian)換(huan)、電(dian)(dian)流變(bian)(bian)(bian)換(huan)、阻抗(kang)變(bian)(bian)(bian)換(huan)、隔離、穩壓(ya)(ya)(ya)(ya)(ya)（磁飽(bao)和變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)）等。按用(yong)途可(ke)以分為(wei)：電(dian)(dian)力變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)和特殊變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)（電(dian)(dian)爐(lu)變(bian)(bian)(bian)、整流變(bian)(bian)(bian)、工(gong)頻(pin)試驗變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)、調壓(ya)(ya)(ya)(ya)(ya)器(qi)、礦用(yong)變(bian)(bian)(bian)、音頻(pin)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)、中頻(pin)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)、高頻(pin)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)、沖擊變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)、儀用(yong)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)、電(dian)(dian)子變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)、電(dian)(dian)抗(kang)器(qi)、互感器(qi)等）。