穩壓(ya)二(er)極管工作在反向擊(ji)穿狀(zhuang)態時，其兩端的電(dian)壓(ya)是基本不變的。利用(yong)這一性質，在電(dian)路里(li)常(chang)用(yong)于構成穩壓(ya)電(dian)路。
穩壓二極管構成的(de)穩壓電(dian)路，雖然穩定度不很高，但(dan)卻具有(you)簡(jian)單、經(jing)濟實用(yong)的(de)優點(dian)，因而應用(yong)非常廣泛。
在實際(ji)電(dian)路(lu)中，要使用好穩壓(ya)二(er)極管，應注意(yi)如(ru)下(xia)幾個問題。
1、要(yao)注(zhu)意一(yi)般(ban)二(er)(er)(er)極(ji)(ji)管(guan)(guan)(guan)(guan)與穩(wen)壓(ya)(ya)二(er)(er)(er)極(ji)(ji)管(guan)(guan)(guan)(guan)的(de)(de)區別方(fang)法。不(bu)少(shao)的(de)(de)一(yi)般(ban)二(er)(er)(er)極(ji)(ji)管(guan)(guan)(guan)(guan)，特別是(shi)玻璃(li)封裝的(de)(de)管(guan)(guan)(guan)(guan)，外(wai)形顏色(se)等與穩(wen)壓(ya)(ya)二(er)(er)(er)極(ji)(ji)管(guan)(guan)(guan)(guan)較相(xiang)似(si)，如不(bu)細(xi)心(xin)區別，就會使用(yong)(yong)錯誤。區別方(fang)法是(shi)：看(kan)(kan)外(wai)形，不(bu)少(shao)穩(wen)壓(ya)(ya)二(er)(er)(er)極(ji)(ji)管(guan)(guan)(guan)(guan)為園柱(zhu)形，較短粗，而一(yi)般(ban)二(er)(er)(er)極(ji)(ji)管(guan)(guan)(guan)(guan)若(ruo)為園柱(zhu)形的(de)(de)則較細(xi)長；看(kan)(kan)標志，穩(wen) 壓(ya)(ya)二(er)(er)(er)極(ji)(ji)管(guan)(guan)(guan)(guan)的(de)(de)外(wai)表(biao)面上(shang)都(dou)標有穩(wen)壓(ya)(ya)值(zhi)(zhi)，如5V6，表(biao)示(shi)穩(wen)壓(ya)(ya)值(zhi)(zhi)為5.6V；用(yong)(yong)萬用(yong)(yong)表(biao)進行測量，根據單向導電性(xing)，用(yong)(yong)X1K擋先把被(bei)測二(er)(er)(er)極(ji)(ji)管(guan)(guan)(guan)(guan)的(de)(de)正負(fu)極(ji)(ji)性(xing)判(pan)斷(duan)出來，然后用(yong)(yong)X10K擋，黑表(biao)筆(bi)(bi)接二(er)(er)(er)極(ji)(ji)管(guan)(guan)(guan)(guan)負(fu)極(ji)(ji)，紅(hong)表(biao)筆(bi)(bi)接二(er)(er)(er)極(ji)(ji)管(guan)(guan)(guan)(guan)正極(ji)(ji)，測的(de)(de)阻(zu)值(zhi)(zhi)與X1K擋時(shi)相(xiang)比，若(ruo)出現(xian)的(de)(de)反向阻(zu)值(zhi)(zhi)很大，為一(yi)般(ban)二(er)(er)(er)極(ji)(ji)管(guan)(guan)(guan)(guan)的(de)(de)可能性(xing)很大，若(ruo)出現(xian)的(de)(de)反向阻(zu)值(zhi)(zhi)變得很小(xiao)，則為穩(wen)壓(ya)(ya)二(er)(er)(er)極(ji)(ji)管(guan)(guan)(guan)(guan)。
2、注意穩(wen)(wen)壓(ya)(ya)二(er)(er)極(ji)管(guan)(guan)(guan)正(zheng)(zheng)(zheng)向(xiang)(xiang)使(shi)用(yong)(yong)(yong)(yong)(yong)與(yu)反(fan)向(xiang)(xiang)使(shi)用(yong)(yong)(yong)(yong)(yong)的(de)(de)(de)區(qu)別。穩(wen)(wen)壓(ya)(ya)二(er)(er)極(ji)管(guan)(guan)(guan)正(zheng)(zheng)(zheng)向(xiang)(xiang)導(dao)(dao)通(tong)使(shi)用(yong)(yong)(yong)(yong)(yong)時，與(yu)一(yi)(yi)般二(er)(er)極(ji)管(guan)(guan)(guan)正(zheng)(zheng)(zheng)向(xiang)(xiang)導(dao)(dao)通(tong)使(shi)用(yong)(yong)(yong)(yong)(yong)時基(ji)本(ben)相同，正(zheng)(zheng)(zheng)向(xiang)(xiang)導(dao)(dao)通(tong)后(hou)兩(liang)端(duan)電壓(ya)(ya)也是基(ji)本(ben)不變的(de)(de)(de)，都約為0.7V。從理(li)論上講，穩(wen)(wen)壓(ya)(ya)二(er)(er)極(ji)管(guan)(guan)(guan)也可正(zheng)(zheng)(zheng)向(xiang)(xiang)使(shi)用(yong)(yong)(yong)(yong)(yong)做(zuo)穩(wen)(wen)壓(ya)(ya)管(guan)(guan)(guan)用(yong)(yong)(yong)(yong)(yong)，但其(qi)穩(wen)(wen)壓(ya)(ya)值(zhi)將(jiang)低于1V，且(qie)穩(wen)(wen)壓(ya)(ya)性能(neng)也不好，一(yi)(yi)般不單獨用(yong)(yong)(yong)(yong)(yong)穩(wen)(wen)壓(ya)(ya)管(guan)(guan)(guan)的(de)(de)(de)正(zheng)(zheng)(zheng)向(xiang)(xiang)導(dao)(dao)通(tong)特(te)性來(lai)(lai)穩(wen)(wen)壓(ya)(ya)，而是用(yong)(yong)(yong)(yong)(yong)反(fan)向(xiang)(xiang)擊(ji)穿(chuan)特(te)性來(lai)(lai)穩(wen)(wen)壓(ya)(ya)。反(fan)向(xiang)(xiang)擊(ji)穿(chuan)電壓(ya)(ya)值(zhi)即為穩(wen)(wen)壓(ya)(ya)值(zhi)。有時將(jiang)兩(liang)個穩(wen)(wen)壓(ya)(ya)管(guan)(guan)(guan)串聯使(shi)用(yong)(yong)(yong)(yong)(yong)，一(yi)(yi)個利(li)用(yong)(yong)(yong)(yong)(yong)它(ta)的(de)(de)(de)正(zheng)(zheng)(zheng)向(xiang)(xiang)特(te)性，另一(yi)(yi)個利(li)用(yong)(yong)(yong)(yong)(yong)它(ta)的(de)(de)(de)反(fan)向(xiang)(xiang)特(te)性，則既能(neng)穩(wen)(wen)壓(ya)(ya)又可起溫(wen)度(du)補(bu)償作用(yong)(yong)(yong)(yong)(yong)，以提(ti)高穩(wen)(wen)壓(ya)(ya)效果。
3、要(yao)注意限(xian)流(liu)(liu)電(dian)(dian)阻(zu)(zu)的(de)作用及(ji)阻(zu)(zu)值大(da)小的(de)影(ying)響。在(zai)穩(wen)壓(ya)(ya)(ya)二極管穩(wen)壓(ya)(ya)(ya)電(dian)(dian)路中(zhong)，一(yi)般都要(yao)串接一(yi)個電(dian)(dian)阻(zu)(zu)R，如圖1或2示。該(gai)電(dian)(dian)阻(zu)(zu)在(zai)電(dian)(dian)路中(zhong)起(qi)限(xian)流(liu)(liu)和(he)提高(gao)穩(wen)壓(ya)(ya)(ya)效(xiao)果(guo)的(de)作用。若不加該(gai)電(dian)(dian)阻(zu)(zu)即當R=0時(shi)，容易(yi)燒壞穩(wen)壓(ya)(ya)(ya)管，穩(wen)壓(ya)(ya)(ya)效(xiao)果(guo)也會極差。限(xian)流(liu)(liu)電(dian)(dian)阻(zu)(zu)的(de)阻(zu)(zu)值越(yue)大(da)，電(dian)(dian)路穩(wen)壓(ya)(ya)(ya)性能(neng)越(yue)好(hao)，但輸入(ru)與輸出(chu)壓(ya)(ya)(ya)差也會過大(da)，耗電(dian)(dian)也就(jiu)越(yue)多。
4、要注意輸(shu)入(ru)與輸(shu)出的(de)壓(ya)(ya)(ya)差。正常使(shi)用(yong)時，穩(wen)(wen)壓(ya)(ya)(ya)二(er)極(ji)管(guan)穩(wen)(wen)壓(ya)(ya)(ya)電路(lu)的(de)輸(shu)出電壓(ya)(ya)(ya)等于穩(wen)(wen)壓(ya)(ya)(ya)管(guan)反向擊穿后兩端的(de)穩(wen)(wen)壓(ya)(ya)(ya)值(zhi)，若輸(shu)入(ru)到穩(wen)(wen)壓(ya)(ya)(ya)電路(lu)中的(de)電壓(ya)(ya)(ya)值(zhi)小于穩(wen)(wen)壓(ya)(ya)(ya)管(guan)的(de)穩(wen)(wen)壓(ya)(ya)(ya)值(zhi)，則電路(lu)將失去穩(wen)(wen)壓(ya)(ya)(ya)作用(yong)，只(zhi)有是大于關系(xi)時，才有穩(wen)(wen)壓(ya)(ya)(ya)作用(yong)，并(bing)且(qie)壓(ya)(ya)(ya)差越大，限流(liu)電阻(zu)的(de)阻(zu)值(zhi)也應越大，否則會損壞穩(wen)(wen)壓(ya)(ya)(ya)管(guan)。
5、穩(wen)壓(ya)管(guan)(guan)(guan)可串(chuan)聯使(shi)用(yong)。幾個(ge)穩(wen)壓(ya)管(guan)(guan)(guan)串(chuan)聯后，可獲(huo)得(de)多個(ge)不(bu)同(tong)的穩(wen)壓(ya)值(zhi)(zhi)(zhi)，故串(chuan)聯使(shi)用(yong)較常見。下面舉例說明(ming)兩個(ge)穩(wen)壓(ya)管(guan)(guan)(guan)串(chuan)聯使(shi)用(yong)后，如何(he)求(qiu)得(de)穩(wen)壓(ya)值(zhi)(zhi)(zhi)。若一(yi)個(ge)穩(wen)壓(ya)管(guan)(guan)(guan)的穩(wen)壓(ya)值(zhi)(zhi)(zhi)為5.6V，另一(yi)個(ge)穩(wen)壓(ya)值(zhi)(zhi)(zhi)為3.6V，設穩(wen)壓(ya)管(guan)(guan)(guan)正向導通時(shi)電壓(ya)均為0.7V，則串(chuan)聯后共(gong)有四種不(bu)同(tong)的穩(wen)壓(ya)值(zhi)(zhi)(zhi)，如圖1示。
6、穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)一(yi)(yi)般(ban)不并(bing)(bing)聯(lian)使用。幾個(ge)(ge)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)并(bing)(bing)聯(lian)后，穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值將由最(zui)低(包括正向導通(tong)后的(de)電壓(ya)(ya)(ya)(ya)值)的(de)一(yi)(yi)個(ge)(ge)來(lai)(lai)決(jue)定(ding)。還是以上述兩個(ge)(ge)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)為例(li)，來(lai)(lai)說(shuo)明(ming)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值的(de)計算(suan)方(fang)法。兩個(ge)(ge)并(bing)(bing)聯(lian)后共有(you)四種情(qing)況，穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值只有(you)兩個(ge)(ge)。除非特(te)殊情(qing)況，穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)二(er)極管(guan)都不并(bing)(bing)聯(lian)使用。
