穩壓(ya)二極管工(gong)作在反(fan)向擊穿狀態時，其兩端的(de)電(dian)壓(ya)是基(ji)本不(bu)變(bian)的(de)。利(li)用(yong)這(zhe)一性質(zhi)，在電(dian)路(lu)里常用(yong)于構成穩壓(ya)電(dian)路(lu)。
穩(wen)壓二極管構成(cheng)的穩(wen)壓電(dian)路(lu)，雖然(ran)穩(wen)定度不很高，但卻具有(you)簡單、經濟實用的優點，因而應用非常廣泛。
在實際電路中，要使用好(hao)穩(wen)壓(ya)二極管，應注意(yi)如(ru)下幾個問題。
1、要注意一(yi)(yi)般二(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)與穩(wen)(wen)壓二(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)的(de)(de)區(qu)別(bie)方法(fa)(fa)。不少的(de)(de)一(yi)(yi)般二(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)，特別(bie)是玻璃封裝的(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)，外形(xing)顏色等與穩(wen)(wen)壓二(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)較(jiao)相(xiang)(xiang)似，如(ru)不細心(xin)區(qu)別(bie)，就會使用(yong)(yong)錯誤。區(qu)別(bie)方法(fa)(fa)是：看(kan)外形(xing)，不少穩(wen)(wen)壓二(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)為園柱(zhu)形(xing)，較(jiao)短粗，而(er)一(yi)(yi)般二(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)若(ruo)(ruo)為園柱(zhu)形(xing)的(de)(de)則較(jiao)細長；看(kan)標志，穩(wen)(wen) 壓二(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)的(de)(de)外表(biao)(biao)面上(shang)都標有穩(wen)(wen)壓值(zhi)(zhi)，如(ru)5V6，表(biao)(biao)示穩(wen)(wen)壓值(zhi)(zhi)為5.6V；用(yong)(yong)萬(wan)用(yong)(yong)表(biao)(biao)進行測量，根據單向導電性，用(yong)(yong)X1K擋(dang)先把被(bei)測二(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)的(de)(de)正(zheng)負極(ji)(ji)(ji)(ji)(ji)(ji)性判斷出來，然后(hou)用(yong)(yong)X10K擋(dang)，黑表(biao)(biao)筆(bi)接(jie)二(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)負極(ji)(ji)(ji)(ji)(ji)(ji)，紅表(biao)(biao)筆(bi)接(jie)二(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)正(zheng)極(ji)(ji)(ji)(ji)(ji)(ji)，測的(de)(de)阻值(zhi)(zhi)與X1K擋(dang)時相(xiang)(xiang)比，若(ruo)(ruo)出現的(de)(de)反向阻值(zhi)(zhi)很大(da)，為一(yi)(yi)般二(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)的(de)(de)可能性很大(da)，若(ruo)(ruo)出現的(de)(de)反向阻值(zhi)(zhi)變得(de)很小(xiao)，則為穩(wen)(wen)壓二(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)。
2、注意穩(wen)(wen)壓(ya)(ya)(ya)二極管(guan)(guan)正向(xiang)(xiang)(xiang)(xiang)使(shi)用(yong)(yong)與反(fan)向(xiang)(xiang)(xiang)(xiang)使(shi)用(yong)(yong)的(de)(de)(de)區別。穩(wen)(wen)壓(ya)(ya)(ya)二極管(guan)(guan)正向(xiang)(xiang)(xiang)(xiang)導通(tong)使(shi)用(yong)(yong)時，與一般二極管(guan)(guan)正向(xiang)(xiang)(xiang)(xiang)導通(tong)使(shi)用(yong)(yong)時基(ji)本相同，正向(xiang)(xiang)(xiang)(xiang)導通(tong)后兩(liang)端(duan)電壓(ya)(ya)(ya)也(ye)(ye)是(shi)基(ji)本不(bu)變的(de)(de)(de)，都約為(wei)0.7V。從理論(lun)上(shang)講(jiang)，穩(wen)(wen)壓(ya)(ya)(ya)二極管(guan)(guan)也(ye)(ye)可(ke)正向(xiang)(xiang)(xiang)(xiang)使(shi)用(yong)(yong)做穩(wen)(wen)壓(ya)(ya)(ya)管(guan)(guan)用(yong)(yong)，但其穩(wen)(wen)壓(ya)(ya)(ya)值(zhi)將低于(yu)1V，且穩(wen)(wen)壓(ya)(ya)(ya)性(xing)能(neng)也(ye)(ye)不(bu)好(hao)，一般不(bu)單獨用(yong)(yong)穩(wen)(wen)壓(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)正向(xiang)(xiang)(xiang)(xiang)導通(tong)特(te)性(xing)來穩(wen)(wen)壓(ya)(ya)(ya)，而是(shi)用(yong)(yong)反(fan)向(xiang)(xiang)(xiang)(xiang)擊(ji)穿特(te)性(xing)來穩(wen)(wen)壓(ya)(ya)(ya)。反(fan)向(xiang)(xiang)(xiang)(xiang)擊(ji)穿電壓(ya)(ya)(ya)值(zhi)即為(wei)穩(wen)(wen)壓(ya)(ya)(ya)值(zhi)。有(you)時將兩(liang)個(ge)穩(wen)(wen)壓(ya)(ya)(ya)管(guan)(guan)串聯(lian)使(shi)用(yong)(yong)，一個(ge)利(li)用(yong)(yong)它(ta)的(de)(de)(de)正向(xiang)(xiang)(xiang)(xiang)特(te)性(xing)，另一個(ge)利(li)用(yong)(yong)它(ta)的(de)(de)(de)反(fan)向(xiang)(xiang)(xiang)(xiang)特(te)性(xing)，則既(ji)能(neng)穩(wen)(wen)壓(ya)(ya)(ya)又可(ke)起溫度補償作用(yong)(yong)，以提高穩(wen)(wen)壓(ya)(ya)(ya)效果(guo)。
3、要注意限(xian)流(liu)電(dian)(dian)(dian)阻(zu)(zu)的(de)作用及阻(zu)(zu)值大(da)小的(de)影響。在穩(wen)壓(ya)(ya)(ya)二(er)極管穩(wen)壓(ya)(ya)(ya)電(dian)(dian)(dian)路中，一般都要串接(jie)一個(ge)電(dian)(dian)(dian)阻(zu)(zu)R，如圖1或(huo)2示。該(gai)電(dian)(dian)(dian)阻(zu)(zu)在電(dian)(dian)(dian)路中起限(xian)流(liu)和提高穩(wen)壓(ya)(ya)(ya)效(xiao)果的(de)作用。若不加該(gai)電(dian)(dian)(dian)阻(zu)(zu)即當R=0時，容易燒壞穩(wen)壓(ya)(ya)(ya)管，穩(wen)壓(ya)(ya)(ya)效(xiao)果也會(hui)極差(cha)。限(xian)流(liu)電(dian)(dian)(dian)阻(zu)(zu)的(de)阻(zu)(zu)值越大(da)，電(dian)(dian)(dian)路穩(wen)壓(ya)(ya)(ya)性能越好(hao)，但輸入與輸出壓(ya)(ya)(ya)差(cha)也會(hui)過大(da)，耗電(dian)(dian)(dian)也就(jiu)越多。
4、要注意輸(shu)入與輸(shu)出的壓(ya)(ya)(ya)差。正常使用時，穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)二極管穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)電(dian)(dian)路的輸(shu)出電(dian)(dian)壓(ya)(ya)(ya)等(deng)于(yu)穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)管反向擊(ji)穿后(hou)兩端(duan)的穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)值，若輸(shu)入到(dao)穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)電(dian)(dian)路中的電(dian)(dian)壓(ya)(ya)(ya)值小(xiao)于(yu)穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)管的穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)值，則電(dian)(dian)路將失去(qu)穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)作用，只有是大(da)于(yu)關系時，才有穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)作用，并且壓(ya)(ya)(ya)差越(yue)大(da)，限(xian)流電(dian)(dian)阻的阻值也應(ying)越(yue)大(da)，否則會損壞(huai)穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)管。
5、穩(wen)(wen)(wen)壓(ya)(ya)管可串(chuan)(chuan)(chuan)聯(lian)(lian)使用。幾個(ge)穩(wen)(wen)(wen)壓(ya)(ya)管串(chuan)(chuan)(chuan)聯(lian)(lian)后(hou)，可獲得多個(ge)不(bu)同(tong)(tong)的穩(wen)(wen)(wen)壓(ya)(ya)值(zhi)，故串(chuan)(chuan)(chuan)聯(lian)(lian)使用較常(chang)見(jian)。下面舉例說(shuo)明兩個(ge)穩(wen)(wen)(wen)壓(ya)(ya)管串(chuan)(chuan)(chuan)聯(lian)(lian)使用后(hou)，如(ru)何求得穩(wen)(wen)(wen)壓(ya)(ya)值(zhi)。若(ruo)一個(ge)穩(wen)(wen)(wen)壓(ya)(ya)管的穩(wen)(wen)(wen)壓(ya)(ya)值(zhi)為(wei)5.6V，另一個(ge)穩(wen)(wen)(wen)壓(ya)(ya)值(zhi)為(wei)3.6V，設穩(wen)(wen)(wen)壓(ya)(ya)管正向(xiang)導通時電壓(ya)(ya)均為(wei)0.7V，則串(chuan)(chuan)(chuan)聯(lian)(lian)后(hou)共有四種不(bu)同(tong)(tong)的穩(wen)(wen)(wen)壓(ya)(ya)值(zhi)，如(ru)圖(tu)1示。
6、穩(wen)壓管一般(ban)不并(bing)聯(lian)使用。幾個(ge)(ge)(ge)(ge)穩(wen)壓管并(bing)聯(lian)后(hou)，穩(wen)壓值(zhi)(zhi)將由最低(包括正向導通后(hou)的電壓值(zhi)(zhi))的一個(ge)(ge)(ge)(ge)來決定。還是以上述兩個(ge)(ge)(ge)(ge)穩(wen)壓管為例，來說明穩(wen)壓值(zhi)(zhi)的計算方法。兩個(ge)(ge)(ge)(ge)并(bing)聯(lian)后(hou)共有(you)四種情況，穩(wen)壓值(zhi)(zhi)只有(you)兩個(ge)(ge)(ge)(ge)。除非(fei)特殊情況，穩(wen)壓二極管都不并(bing)聯(lian)使用。
