穩(wen)壓器是(shi)一種能自(zi)動(dong)調整輸(shu)出電壓的供(gong)電電路或供(gong)電設(she)備，其作(zuo)用是(shi)將波動(dong)較大和達不到(dao)電器設(she)備要求的電源電壓穩(wen)定(ding)在它的設(she)定(ding)值(zhi)范圍內，使(shi)各種電路或電器設(she)備能在額(e)定(ding)工作(zuo)電壓下正(zheng)常工作(zuo)。

最初的(de)電(dian)(dian)(dian)(dian)力穩壓(ya)器(qi)是靠繼(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)的(de)跳(tiao)動(dong)(dong)穩定(ding)電(dian)(dian)(dian)(dian)壓(ya)的(de)。當(dang)電(dian)(dian)(dian)(dian)網電(dian)(dian)(dian)(dian)壓(ya)出(chu)現波動(dong)(dong)時，電(dian)(dian)(dian)(dian)力穩壓(ya)器(qi)的(de)自(zi)動(dong)(dong)糾正(zheng)電(dian)(dian)(dian)(dian)路啟動(dong)(dong)，使(shi)內部繼(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)動(dong)(dong)作。迫使(shi)輸出(chu)電(dian)(dian)(dian)(dian)壓(ya)保(bao)持在設(she)定(ding)值附近，這(zhe)種電(dian)(dian)(dian)(dian)路優點(dian)是電(dian)(dian)(dian)(dian)路簡(jian)單，缺點(dian)是穩壓(ya)精(jing)度不高并且每一(yi)次繼(ji)(ji)電(dian)(dian)(dian)(dian)器(qi)跳(tiao)動(dong)(dong)換擋，都(dou)會(hui)使(shi)供電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)源發(fa)生(sheng)一(yi)次瞬時的(de)中斷并產生(sheng)火花干擾。

這對(dui)電腦設備的讀寫工作干擾很大，容(rong)易造(zao)成電腦出現錯誤信號，嚴重時還會使硬盤損壞。

高(gao)質量的(de)(de)小型穩(wen)壓器(qi)，大多采(cai)用電(dian)(dian)機拖動碳刷(shua)的(de)(de)方法穩(wen)定(ding)電(dian)(dian)壓，這(zhe)種穩(wen)壓器(qi)對(dui)電(dian)(dian)器(qi)設(she)備產(chan)生的(de)(de)干擾很小穩(wen)壓精度相對(dui)較高(gao)。