自(zi)耦變(bian)壓(ya)器是輸出和輸入共(gong)(gong)用(yong)(yong)一組線圈(quan)的(de)特殊(shu)變(bian)壓(ya)器,升壓(ya)和降壓(ya)用(yong)(yong)不同的(de)抽頭(tou)來完成,比共(gong)(gong)用(yong)(yong)線圈(quan)少的(de)部(bu)(bu)分(fen)抽頭(tou)電(dian)壓(ya)就(jiu)下降,比共(gong)(gong)用(yong)(yong)線圈(quan)多的(de)部(bu)(bu)分(fen)抽頭(tou)電(dian)壓(ya)就(jiu)升高。