穩(wen)壓(ya)(ya)器是一種能(neng)自動調(diao)整輸出電(dian)(dian)(dian)壓(ya)(ya)的供(gong)電(dian)(dian)(dian)電(dian)(dian)(dian)路或(huo)供(gong)電(dian)(dian)(dian)設(she)(she)備(bei)(bei)，其(qi)作用是將(jiang)波(bo)動較大和達(da)不到電(dian)(dian)(dian)器設(she)(she)備(bei)(bei)要求的電(dian)(dian)(dian)源電(dian)(dian)(dian)壓(ya)(ya)穩(wen)定(ding)在它(ta)的設(she)(she)定(ding)值范圍(wei)內，使各種電(dian)(dian)(dian)路或(huo)電(dian)(dian)(dian)器設(she)(she)備(bei)(bei)能(neng)在額定(ding)工(gong)作電(dian)(dian)(dian)壓(ya)(ya)下正常工(gong)作。

最(zui)初(chu)的電(dian)力穩(wen)壓(ya)(ya)器(qi)是靠繼電(dian)器(qi)的跳(tiao)動(dong)(dong)穩(wen)定電(dian)壓(ya)(ya)的。當電(dian)網電(dian)壓(ya)(ya)出現波(bo)動(dong)(dong)時(shi)，電(dian)力穩(wen)壓(ya)(ya)器(qi)的自動(dong)(dong)糾正(zheng)電(dian)路(lu)啟動(dong)(dong)，使內(nei)部繼電(dian)器(qi)動(dong)(dong)作。迫使輸出電(dian)壓(ya)(ya)保持在設定值(zhi)附(fu)近(jin)，這種電(dian)路(lu)優點(dian)是電(dian)路(lu)簡單，缺(que)點(dian)是穩(wen)壓(ya)(ya)精度不高并且每一(yi)次繼電(dian)器(qi)跳(tiao)動(dong)(dong)換擋，都會(hui)使供電(dian)電(dian)源(yuan)發生(sheng)一(yi)次瞬時(shi)的中斷并產生(sheng)火花干擾。

這對(dui)電腦設備的(de)讀寫(xie)工作干擾很大，容易(yi)造(zao)成電腦出現(xian)錯誤信號，嚴重時還(huan)會使硬盤損壞。

高質量的小(xiao)型穩(wen)(wen)壓(ya)器，大多采用電(dian)機拖動碳刷的方法穩(wen)(wen)定電(dian)壓(ya)，這種穩(wen)(wen)壓(ya)器對電(dian)器設備產生的干擾很小(xiao)穩(wen)(wen)壓(ya)精度相對較高。