二極(ji)管的(de)主(zhu)要(yao)特性是(shi)單向(xiang)導電(dian)性，也(ye)就(jiu)是(shi)在(zai)正向(xiang)電(dian)壓的(de)作(zuo)用(yong)下，導通電(dian)阻很小(xiao);而在(zai)反向(xiang)電(dian)壓作(zuo)用(yong)下導通電(dian)阻極(ji)大(da)或無窮大(da)。正因為二極(ji)管具有上述特性，電(dian)路(lu)中(zhong)常把它用(yong)在(zai)整流、 穩壓電(dian)路(lu)里。

　　穩(wen)(wen)壓(ya)(ya)二(er)(er)(er)極(ji)管(guan)的(de)穩(wen)(wen)壓(ya)(ya)原理：穩(wen)(wen)壓(ya)(ya)二(er)(er)(er)極(ji)管(guan)的(de)特點(dian)(dian)就是加反(fan)(fan)向電(dian)(dian)壓(ya)(ya)擊穿后(hou)，其兩端的(de)電(dian)(dian)壓(ya)(ya)基(ji)本 保(bao)持不變(bian)。而整流二(er)(er)(er)極(ji)管(guan)反(fan)(fan)向擊穿后(hou)就損壞(huai)了.這樣(yang)，當(dang)把穩(wen)(wen)壓(ya)(ya)管(guan)接入電(dian)(dian)路(lu)以后(hou)，若由于電(dian)(dian)源電(dian)(dian)壓(ya)(ya)發生(sheng)波動(dong)， 或(huo)其它原因造成(cheng)電(dian)(dian)路(lu)中(zhong)各點(dian)(dian)電(dian)(dian)壓(ya)(ya)變(bian)動(dong)時，負載兩端的(de)電(dian)(dian)壓(ya)(ya)將基(ji)本保(bao)持不變(bian)。 穩(wen)(wen)壓(ya)(ya)二(er)(er)(er)極(ji)管(guan)用來穩(wen)(wen)壓(ya)(ya)或(huo)在串聯電(dian)(dian)路(lu)中(zhong)作(zuo)基(ji)準(zhun)電(dian)(dian)壓(ya)(ya)

　　整流(liu)二極管(guan)(guan)和穩(wen)壓二極管(guan)(guan)都(dou)是(shi)(shi)PN半導體器(qi)件.所不(bu)同的是(shi)(shi)整流(liu)二極管(guan)(guan)用的是(shi)(shi)單向(xiang)(xiang)(xiang)導電性.穩(wen)壓二極管(guan)(guan)是(shi)(shi)利用了其反(fan)向(xiang)(xiang)(xiang)特性.在電路(lu)中(zhong)反(fan)向(xiang)(xiang)(xiang)聯接.