穩(wen)壓(ya)二極管工作在(zai)反向擊(ji)穿狀態(tai)時(shi)，其兩端的(de)電(dian)壓(ya)是基本不變的(de)。利用這一(yi)性質，在(zai)電(dian)路里常用于構(gou)成穩(wen)壓(ya)電(dian)路。
穩(wen)壓二(er)極管構成(cheng)的穩(wen)壓電路(lu)，雖然(ran)穩(wen)定度(du)不很高，但卻具有簡(jian)單(dan)、經濟實用(yong)的優點(dian)，因(yin)而應用(yong)非常(chang)廣泛。
在實際電路中(zhong)，要使用好穩壓二(er)極管(guan)，應(ying)注意如下(xia)幾個問(wen)題。
1、要注意一般(ban)二(er)(er)(er)(er)(er)極(ji)管(guan)(guan)與(yu)(yu)穩壓(ya)(ya)二(er)(er)(er)(er)(er)極(ji)管(guan)(guan)的(de)(de)(de)區(qu)別方法。不少(shao)的(de)(de)(de)一般(ban)二(er)(er)(er)(er)(er)極(ji)管(guan)(guan)，特(te)別是玻璃封裝的(de)(de)(de)管(guan)(guan)，外形顏色等與(yu)(yu)穩壓(ya)(ya)二(er)(er)(er)(er)(er)極(ji)管(guan)(guan)較(jiao)相似，如不細心區(qu)別，就(jiu)會使用錯誤。區(qu)別方法是：看外形，不少(shao)穩壓(ya)(ya)二(er)(er)(er)(er)(er)極(ji)管(guan)(guan)為(wei)園柱形，較(jiao)短粗，而一般(ban)二(er)(er)(er)(er)(er)極(ji)管(guan)(guan)若為(wei)園柱形的(de)(de)(de)則(ze)較(jiao)細長；看標志，穩 壓(ya)(ya)二(er)(er)(er)(er)(er)極(ji)管(guan)(guan)的(de)(de)(de)外表(biao)面上都標有(you)穩壓(ya)(ya)值，如5V6，表(biao)示穩壓(ya)(ya)值為(wei)5.6V；用萬(wan)用表(biao)進(jin)行測(ce)(ce)量，根(gen)據單向(xiang)導電性(xing)，用X1K擋先把被測(ce)(ce)二(er)(er)(er)(er)(er)極(ji)管(guan)(guan)的(de)(de)(de)正(zheng)(zheng)負極(ji)性(xing)判斷(duan)出(chu)來，然后用X10K擋，黑表(biao)筆(bi)接二(er)(er)(er)(er)(er)極(ji)管(guan)(guan)負極(ji)，紅表(biao)筆(bi)接二(er)(er)(er)(er)(er)極(ji)管(guan)(guan)正(zheng)(zheng)極(ji)，測(ce)(ce)的(de)(de)(de)阻(zu)值與(yu)(yu)X1K擋時相比，若出(chu)現的(de)(de)(de)反向(xiang)阻(zu)值很(hen)(hen)大，為(wei)一般(ban)二(er)(er)(er)(er)(er)極(ji)管(guan)(guan)的(de)(de)(de)可能性(xing)很(hen)(hen)大，若出(chu)現的(de)(de)(de)反向(xiang)阻(zu)值變得(de)很(hen)(hen)小，則(ze)為(wei)穩壓(ya)(ya)二(er)(er)(er)(er)(er)極(ji)管(guan)(guan)。
2、注(zhu)意穩(wen)(wen)壓(ya)(ya)二極管正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)使(shi)(shi)用(yong)(yong)(yong)(yong)與反向(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)使(shi)(shi)用(yong)(yong)(yong)(yong)的(de)區別(bie)。穩(wen)(wen)壓(ya)(ya)二極管正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)導(dao)通使(shi)(shi)用(yong)(yong)(yong)(yong)時(shi)，與一般二極管正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)導(dao)通使(shi)(shi)用(yong)(yong)(yong)(yong)時(shi)基(ji)(ji)本(ben)(ben)相同(tong)，正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)導(dao)通后(hou)兩端(duan)電壓(ya)(ya)也是(shi)基(ji)(ji)本(ben)(ben)不(bu)(bu)變(bian)的(de)，都約為(wei)0.7V。從理論上講(jiang)，穩(wen)(wen)壓(ya)(ya)二極管也可(ke)正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)使(shi)(shi)用(yong)(yong)(yong)(yong)做穩(wen)(wen)壓(ya)(ya)管用(yong)(yong)(yong)(yong)，但其穩(wen)(wen)壓(ya)(ya)值(zhi)將(jiang)低于1V，且穩(wen)(wen)壓(ya)(ya)性(xing)能也不(bu)(bu)好，一般不(bu)(bu)單獨用(yong)(yong)(yong)(yong)穩(wen)(wen)壓(ya)(ya)管的(de)正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)導(dao)通特(te)性(xing)來穩(wen)(wen)壓(ya)(ya)，而(er)是(shi)用(yong)(yong)(yong)(yong)反向(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)擊穿特(te)性(xing)來穩(wen)(wen)壓(ya)(ya)。反向(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)擊穿電壓(ya)(ya)值(zhi)即(ji)為(wei)穩(wen)(wen)壓(ya)(ya)值(zhi)。有時(shi)將(jiang)兩個穩(wen)(wen)壓(ya)(ya)管串聯(lian)使(shi)(shi)用(yong)(yong)(yong)(yong)，一個利用(yong)(yong)(yong)(yong)它的(de)正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)特(te)性(xing)，另一個利用(yong)(yong)(yong)(yong)它的(de)反向(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)特(te)性(xing)，則既能穩(wen)(wen)壓(ya)(ya)又可(ke)起溫(wen)度補償作用(yong)(yong)(yong)(yong)，以提高穩(wen)(wen)壓(ya)(ya)效果(guo)。
3、要注意限(xian)流電(dian)阻(zu)的作用(yong)及(ji)阻(zu)值大小(xiao)的影(ying)響。在穩(wen)壓(ya)(ya)二極管穩(wen)壓(ya)(ya)電(dian)路(lu)中，一(yi)般都要串接一(yi)個電(dian)阻(zu)R，如圖1或2示。該電(dian)阻(zu)在電(dian)路(lu)中起限(xian)流和提高(gao)穩(wen)壓(ya)(ya)效(xiao)果的作用(yong)。若不加該電(dian)阻(zu)即當(dang)R=0時，容易燒(shao)壞穩(wen)壓(ya)(ya)管，穩(wen)壓(ya)(ya)效(xiao)果也會極差。限(xian)流電(dian)阻(zu)的阻(zu)值越大，電(dian)路(lu)穩(wen)壓(ya)(ya)性(xing)能越好，但輸(shu)入(ru)與(yu)輸(shu)出壓(ya)(ya)差也會過大，耗電(dian)也就越多(duo)。
4、要注意輸入與輸出的(de)(de)(de)壓(ya)(ya)(ya)差。正常(chang)使用(yong)時，穩(wen)(wen)壓(ya)(ya)(ya)二極管(guan)穩(wen)(wen)壓(ya)(ya)(ya)電(dian)路的(de)(de)(de)輸出電(dian)壓(ya)(ya)(ya)等于(yu)(yu)穩(wen)(wen)壓(ya)(ya)(ya)管(guan)反(fan)向擊穿后兩端的(de)(de)(de)穩(wen)(wen)壓(ya)(ya)(ya)值(zhi)(zhi)，若輸入到穩(wen)(wen)壓(ya)(ya)(ya)電(dian)路中的(de)(de)(de)電(dian)壓(ya)(ya)(ya)值(zhi)(zhi)小于(yu)(yu)穩(wen)(wen)壓(ya)(ya)(ya)管(guan)的(de)(de)(de)穩(wen)(wen)壓(ya)(ya)(ya)值(zhi)(zhi)，則(ze)電(dian)路將失(shi)去穩(wen)(wen)壓(ya)(ya)(ya)作用(yong)，只有是大(da)(da)于(yu)(yu)關系(xi)時，才有穩(wen)(wen)壓(ya)(ya)(ya)作用(yong)，并且壓(ya)(ya)(ya)差越(yue)大(da)(da)，限(xian)流電(dian)阻的(de)(de)(de)阻值(zhi)(zhi)也應越(yue)大(da)(da)，否則(ze)會損壞(huai)穩(wen)(wen)壓(ya)(ya)(ya)管(guan)。
5、穩(wen)(wen)壓(ya)管(guan)可(ke)串(chuan)聯使用。幾個(ge)穩(wen)(wen)壓(ya)管(guan)串(chuan)聯后，可(ke)獲得(de)多個(ge)不(bu)同(tong)的穩(wen)(wen)壓(ya)值，故串(chuan)聯使用較常見。下(xia)面舉例說明兩個(ge)穩(wen)(wen)壓(ya)管(guan)串(chuan)聯使用后，如(ru)(ru)何(he)求得(de)穩(wen)(wen)壓(ya)值。若一(yi)(yi)個(ge)穩(wen)(wen)壓(ya)管(guan)的穩(wen)(wen)壓(ya)值為5.6V，另一(yi)(yi)個(ge)穩(wen)(wen)壓(ya)值為3.6V，設(she)穩(wen)(wen)壓(ya)管(guan)正(zheng)向導通時電壓(ya)均(jun)為0.7V，則(ze)串(chuan)聯后共有四(si)種不(bu)同(tong)的穩(wen)(wen)壓(ya)值，如(ru)(ru)圖(tu)1示(shi)。
6、穩(wen)壓(ya)管(guan)(guan)一般不(bu)并(bing)(bing)(bing)聯(lian)(lian)使(shi)用。幾個(ge)(ge)穩(wen)壓(ya)管(guan)(guan)并(bing)(bing)(bing)聯(lian)(lian)后，穩(wen)壓(ya)值(zhi)(zhi)將由(you)最低(包括(kuo)正向導(dao)通后的電壓(ya)值(zhi)(zhi))的一個(ge)(ge)來決定。還是以上述兩個(ge)(ge)穩(wen)壓(ya)管(guan)(guan)為(wei)例，來說明穩(wen)壓(ya)值(zhi)(zhi)的計算方法。兩個(ge)(ge)并(bing)(bing)(bing)聯(lian)(lian)后共有四種情(qing)(qing)況，穩(wen)壓(ya)值(zhi)(zhi)只有兩個(ge)(ge)。除非特殊情(qing)(qing)況，穩(wen)壓(ya)二極管(guan)(guan)都不(bu)并(bing)(bing)(bing)聯(lian)(lian)使(shi)用。
