穩壓二極管工(gong)作在反向(xiang)擊(ji)穿狀態時，其兩端的電壓是基本不(bu)變的。利用(yong)這(zhe)一性質(zhi)，在電路(lu)里常用(yong)于(yu)構成穩壓電路(lu)。
穩(wen)壓(ya)二極管(guan)構(gou)成的穩(wen)壓(ya)電路，雖然穩(wen)定度不很高，但卻具有(you)簡(jian)單、經濟實用(yong)的優點，因而應用(yong)非常廣(guang)泛。
在實際電路中，要使(shi)用好穩(wen)壓(ya)二(er)極(ji)管，應(ying)注意如下幾個問(wen)題。
1、要注意一般(ban)二(er)(er)極(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)與(yu)穩(wen)壓二(er)(er)極(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)區(qu)別(bie)方(fang)法。不少(shao)的(de)(de)一般(ban)二(er)(er)極(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)，特別(bie)是(shi)玻璃封裝的(de)(de)管(guan)(guan)(guan)，外形顏色(se)等(deng)與(yu)穩(wen)壓二(er)(er)極(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)較相似，如(ru)不細(xi)心區(qu)別(bie)，就會使用(yong)(yong)錯誤。區(qu)別(bie)方(fang)法是(shi)：看外形，不少(shao)穩(wen)壓二(er)(er)極(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)為(wei)園柱(zhu)形，較短粗，而一般(ban)二(er)(er)極(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)若(ruo)為(wei)園柱(zhu)形的(de)(de)則較細(xi)長；看標(biao)(biao)志，穩(wen) 壓二(er)(er)極(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)外表(biao)面上都(dou)標(biao)(biao)有穩(wen)壓值(zhi)，如(ru)5V6，表(biao)示穩(wen)壓值(zhi)為(wei)5.6V；用(yong)(yong)萬用(yong)(yong)表(biao)進行(xing)測量，根據單向導電性(xing)，用(yong)(yong)X1K擋先把被測二(er)(er)極(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)正負(fu)極(ji)(ji)(ji)(ji)(ji)性(xing)判斷出(chu)來(lai)，然(ran)后用(yong)(yong)X10K擋，黑表(biao)筆(bi)接(jie)二(er)(er)極(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)負(fu)極(ji)(ji)(ji)(ji)(ji)，紅表(biao)筆(bi)接(jie)二(er)(er)極(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)正極(ji)(ji)(ji)(ji)(ji)，測的(de)(de)阻值(zhi)與(yu)X1K擋時相比，若(ruo)出(chu)現的(de)(de)反向阻值(zhi)很大，為(wei)一般(ban)二(er)(er)極(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)可能性(xing)很大，若(ruo)出(chu)現的(de)(de)反向阻值(zhi)變得很小，則為(wei)穩(wen)壓二(er)(er)極(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)。
2、注(zhu)意穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)二(er)(er)(er)極管(guan)正向(xiang)(xiang)使(shi)(shi)用與反向(xiang)(xiang)使(shi)(shi)用的(de)(de)區別。穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)二(er)(er)(er)極管(guan)正向(xiang)(xiang)導通使(shi)(shi)用時(shi)(shi)，與一般二(er)(er)(er)極管(guan)正向(xiang)(xiang)導通使(shi)(shi)用時(shi)(shi)基(ji)本相同，正向(xiang)(xiang)導通后兩(liang)端電壓(ya)(ya)(ya)也(ye)是基(ji)本不變的(de)(de)，都約為(wei)0.7V。從(cong)理論上講，穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)二(er)(er)(er)極管(guan)也(ye)可(ke)正向(xiang)(xiang)使(shi)(shi)用做穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)管(guan)用，但其穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)值將(jiang)低于1V，且(qie)穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)性(xing)(xing)(xing)能(neng)也(ye)不好，一般不單獨用穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)管(guan)的(de)(de)正向(xiang)(xiang)導通特(te)性(xing)(xing)(xing)來(lai)穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)，而(er)是用反向(xiang)(xiang)擊穿特(te)性(xing)(xing)(xing)來(lai)穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)。反向(xiang)(xiang)擊穿電壓(ya)(ya)(ya)值即為(wei)穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)值。有時(shi)(shi)將(jiang)兩(liang)個穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)管(guan)串聯使(shi)(shi)用，一個利(li)用它的(de)(de)正向(xiang)(xiang)特(te)性(xing)(xing)(xing)，另一個利(li)用它的(de)(de)反向(xiang)(xiang)特(te)性(xing)(xing)(xing)，則既能(neng)穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)又(you)可(ke)起溫度(du)補償(chang)作用，以提(ti)高穩(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)效果。
3、要注意限(xian)流(liu)電(dian)阻的(de)(de)(de)作用及阻值大(da)(da)小的(de)(de)(de)影響。在穩(wen)壓(ya)(ya)二極管穩(wen)壓(ya)(ya)電(dian)路中，一(yi)般(ban)都要串接一(yi)個電(dian)阻R，如圖1或2示。該(gai)電(dian)阻在電(dian)路中起限(xian)流(liu)和提高穩(wen)壓(ya)(ya)效果的(de)(de)(de)作用。若不加該(gai)電(dian)阻即當R=0時，容易燒壞穩(wen)壓(ya)(ya)管，穩(wen)壓(ya)(ya)效果也(ye)(ye)會極差。限(xian)流(liu)電(dian)阻的(de)(de)(de)阻值越大(da)(da)，電(dian)路穩(wen)壓(ya)(ya)性能(neng)越好，但輸入與輸出(chu)壓(ya)(ya)差也(ye)(ye)會過大(da)(da)，耗電(dian)也(ye)(ye)就越多(duo)。
4、要注意(yi)輸(shu)入與輸(shu)出(chu)的(de)(de)壓(ya)差(cha)。正常(chang)使(shi)用(yong)時(shi)，穩(wen)(wen)壓(ya)二極管(guan)(guan)穩(wen)(wen)壓(ya)電(dian)路的(de)(de)輸(shu)出(chu)電(dian)壓(ya)等(deng)于穩(wen)(wen)壓(ya)管(guan)(guan)反向擊穿后兩端(duan)的(de)(de)穩(wen)(wen)壓(ya)值(zhi)，若(ruo)輸(shu)入到穩(wen)(wen)壓(ya)電(dian)路中(zhong)的(de)(de)電(dian)壓(ya)值(zhi)小于穩(wen)(wen)壓(ya)管(guan)(guan)的(de)(de)穩(wen)(wen)壓(ya)值(zhi)，則電(dian)路將失(shi)去(qu)穩(wen)(wen)壓(ya)作用(yong)，只有(you)是大(da)于關系(xi)時(shi)，才有(you)穩(wen)(wen)壓(ya)作用(yong)，并且壓(ya)差(cha)越大(da)，限流(liu)電(dian)阻的(de)(de)阻值(zhi)也應(ying)越大(da)，否(fou)則會損壞穩(wen)(wen)壓(ya)管(guan)(guan)。
5、穩(wen)壓(ya)(ya)管(guan)(guan)可串(chuan)(chuan)聯使用。幾個(ge)穩(wen)壓(ya)(ya)管(guan)(guan)串(chuan)(chuan)聯后，可獲(huo)得多個(ge)不同的穩(wen)壓(ya)(ya)值，故串(chuan)(chuan)聯使用較常見。下面(mian)舉(ju)例說明(ming)兩個(ge)穩(wen)壓(ya)(ya)管(guan)(guan)串(chuan)(chuan)聯使用后，如(ru)何求得穩(wen)壓(ya)(ya)值。若(ruo)一(yi)個(ge)穩(wen)壓(ya)(ya)管(guan)(guan)的穩(wen)壓(ya)(ya)值為5.6V，另(ling)一(yi)個(ge)穩(wen)壓(ya)(ya)值為3.6V，設穩(wen)壓(ya)(ya)管(guan)(guan)正向導通時電壓(ya)(ya)均為0.7V，則串(chuan)(chuan)聯后共有四種不同的穩(wen)壓(ya)(ya)值，如(ru)圖1示(shi)。
6、穩(wen)壓(ya)(ya)管一(yi)(yi)般不并(bing)(bing)聯使(shi)用。幾個(ge)(ge)穩(wen)壓(ya)(ya)管并(bing)(bing)聯后(hou)(hou)，穩(wen)壓(ya)(ya)值將(jiang)由最低(di)(包括正向導通后(hou)(hou)的(de)電壓(ya)(ya)值)的(de)一(yi)(yi)個(ge)(ge)來(lai)決(jue)定。還(huan)是以上述兩個(ge)(ge)穩(wen)壓(ya)(ya)管為例，來(lai)說明穩(wen)壓(ya)(ya)值的(de)計(ji)算方法。兩個(ge)(ge)并(bing)(bing)聯后(hou)(hou)共有(you)四種情況(kuang)，穩(wen)壓(ya)(ya)值只有(you)兩個(ge)(ge)。除(chu)非特殊(shu)情況(kuang)，穩(wen)壓(ya)(ya)二極管都不并(bing)(bing)聯使(shi)用。
