穩壓(ya)(ya)二極(ji)管工作在反(fan)向擊穿(chuan)狀態時，其(qi)兩端的(de)電(dian)壓(ya)(ya)是基(ji)本不(bu)變的(de)。利用這一性質，在電(dian)路(lu)里常用于構成(cheng)穩壓(ya)(ya)電(dian)路(lu)。
穩壓二極管構(gou)成的(de)穩壓電路，雖然(ran)穩定度不很高，但卻具(ju)有簡單、經(jing)濟實用(yong)的(de)優點，因而應用(yong)非常(chang)廣泛。
在(zai)實(shi)際電路中，要使用好(hao)穩壓二極(ji)管，應注(zhu)意(yi)如(ru)下幾個問題。
1、要注意(yi)一(yi)般二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)與(yu)穩(wen)壓(ya)二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)的(de)(de)區別方(fang)法。不少的(de)(de)一(yi)般二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)，特(te)別是玻璃封裝的(de)(de)管(guan)(guan)(guan)(guan)(guan)，外(wai)形(xing)顏色等與(yu)穩(wen)壓(ya)二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)較(jiao)相似，如不細心區別，就(jiu)會使用(yong)錯誤。區別方(fang)法是：看外(wai)形(xing)，不少穩(wen)壓(ya)二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)為(wei)園柱形(xing)，較(jiao)短粗，而一(yi)般二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)若為(wei)園柱形(xing)的(de)(de)則較(jiao)細長；看標志，穩(wen) 壓(ya)二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)的(de)(de)外(wai)表(biao)(biao)面上(shang)都(dou)標有穩(wen)壓(ya)值，如5V6，表(biao)(biao)示(shi)穩(wen)壓(ya)值為(wei)5.6V；用(yong)萬(wan)用(yong)表(biao)(biao)進(jin)行測(ce)(ce)量，根(gen)據單(dan)向導電性(xing)(xing)，用(yong)X1K擋(dang)(dang)先把被測(ce)(ce)二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)的(de)(de)正負極(ji)(ji)(ji)性(xing)(xing)判(pan)斷出來(lai)，然后用(yong)X10K擋(dang)(dang)，黑(hei)表(biao)(biao)筆(bi)接二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)負極(ji)(ji)(ji)，紅表(biao)(biao)筆(bi)接二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)正極(ji)(ji)(ji)，測(ce)(ce)的(de)(de)阻值與(yu)X1K擋(dang)(dang)時相比，若出現的(de)(de)反向阻值很大，為(wei)一(yi)般二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)的(de)(de)可能性(xing)(xing)很大，若出現的(de)(de)反向阻值變(bian)得(de)很小，則為(wei)穩(wen)壓(ya)二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)(guan)(guan)。
2、注意穩(wen)(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)二(er)(er)極(ji)管正(zheng)(zheng)向(xiang)使(shi)(shi)(shi)用(yong)(yong)(yong)(yong)與(yu)反(fan)向(xiang)使(shi)(shi)(shi)用(yong)(yong)(yong)(yong)的(de)區(qu)別。穩(wen)(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)二(er)(er)極(ji)管正(zheng)(zheng)向(xiang)導通(tong)使(shi)(shi)(shi)用(yong)(yong)(yong)(yong)時，與(yu)一般二(er)(er)極(ji)管正(zheng)(zheng)向(xiang)導通(tong)使(shi)(shi)(shi)用(yong)(yong)(yong)(yong)時基本相同，正(zheng)(zheng)向(xiang)導通(tong)后兩端電壓(ya)(ya)(ya)(ya)也是(shi)基本不變的(de)，都約為(wei)(wei)0.7V。從理(li)論上講，穩(wen)(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)二(er)(er)極(ji)管也可正(zheng)(zheng)向(xiang)使(shi)(shi)(shi)用(yong)(yong)(yong)(yong)做(zuo)穩(wen)(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管用(yong)(yong)(yong)(yong)，但其穩(wen)(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值(zhi)將低于1V，且(qie)穩(wen)(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)性(xing)能也不好(hao)，一般不單獨用(yong)(yong)(yong)(yong)穩(wen)(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管的(de)正(zheng)(zheng)向(xiang)導通(tong)特(te)(te)性(xing)來穩(wen)(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)，而是(shi)用(yong)(yong)(yong)(yong)反(fan)向(xiang)擊(ji)穿特(te)(te)性(xing)來穩(wen)(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)。反(fan)向(xiang)擊(ji)穿電壓(ya)(ya)(ya)(ya)值(zhi)即為(wei)(wei)穩(wen)(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值(zhi)。有時將兩個(ge)穩(wen)(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管串聯使(shi)(shi)(shi)用(yong)(yong)(yong)(yong)，一個(ge)利用(yong)(yong)(yong)(yong)它(ta)的(de)正(zheng)(zheng)向(xiang)特(te)(te)性(xing)，另一個(ge)利用(yong)(yong)(yong)(yong)它(ta)的(de)反(fan)向(xiang)特(te)(te)性(xing)，則既能穩(wen)(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)又(you)可起溫度補(bu)償(chang)作用(yong)(yong)(yong)(yong)，以(yi)提高穩(wen)(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)效果。
3、要注(zhu)意限流(liu)電(dian)(dian)阻(zu)(zu)的(de)作(zuo)用(yong)及(ji)阻(zu)(zu)值大小的(de)影響。在穩(wen)(wen)壓(ya)(ya)二(er)極管穩(wen)(wen)壓(ya)(ya)電(dian)(dian)路中，一般都(dou)要串接一個電(dian)(dian)阻(zu)(zu)R，如圖1或2示。該電(dian)(dian)阻(zu)(zu)在電(dian)(dian)路中起限流(liu)和(he)提高穩(wen)(wen)壓(ya)(ya)效(xiao)果(guo)的(de)作(zuo)用(yong)。若(ruo)不加(jia)該電(dian)(dian)阻(zu)(zu)即當R=0時(shi)，容易燒壞穩(wen)(wen)壓(ya)(ya)管，穩(wen)(wen)壓(ya)(ya)效(xiao)果(guo)也會極差。限流(liu)電(dian)(dian)阻(zu)(zu)的(de)阻(zu)(zu)值越大，電(dian)(dian)路穩(wen)(wen)壓(ya)(ya)性能越好，但輸入(ru)與輸出壓(ya)(ya)差也會過大，耗(hao)電(dian)(dian)也就越多。
4、要注意輸(shu)入與輸(shu)出的壓(ya)差(cha)。正常使用(yong)時(shi)，穩壓(ya)二極(ji)管穩壓(ya)電(dian)路的輸(shu)出電(dian)壓(ya)等(deng)于穩壓(ya)管反向(xiang)擊穿后(hou)兩(liang)端(duan)的穩壓(ya)值(zhi)(zhi)，若輸(shu)入到穩壓(ya)電(dian)路中的電(dian)壓(ya)值(zhi)(zhi)小于穩壓(ya)管的穩壓(ya)值(zhi)(zhi)，則(ze)電(dian)路將失去穩壓(ya)作(zuo)用(yong)，只有是大于關系(xi)時(shi)，才有穩壓(ya)作(zuo)用(yong)，并且壓(ya)差(cha)越大，限流電(dian)阻的阻值(zhi)(zhi)也(ye)應越大，否(fou)則(ze)會損壞(huai)穩壓(ya)管。
5、穩(wen)(wen)(wen)(wen)(wen)壓(ya)管(guan)可(ke)串(chuan)(chuan)聯(lian)使(shi)用。幾個(ge)(ge)穩(wen)(wen)(wen)(wen)(wen)壓(ya)管(guan)串(chuan)(chuan)聯(lian)后(hou)，可(ke)獲得(de)多個(ge)(ge)不同(tong)的穩(wen)(wen)(wen)(wen)(wen)壓(ya)值，故串(chuan)(chuan)聯(lian)使(shi)用較(jiao)常見。下面舉例(li)說(shuo)明兩個(ge)(ge)穩(wen)(wen)(wen)(wen)(wen)壓(ya)管(guan)串(chuan)(chuan)聯(lian)使(shi)用后(hou)，如何(he)求得(de)穩(wen)(wen)(wen)(wen)(wen)壓(ya)值。若(ruo)一個(ge)(ge)穩(wen)(wen)(wen)(wen)(wen)壓(ya)管(guan)的穩(wen)(wen)(wen)(wen)(wen)壓(ya)值為(wei)5.6V，另一個(ge)(ge)穩(wen)(wen)(wen)(wen)(wen)壓(ya)值為(wei)3.6V，設(she)穩(wen)(wen)(wen)(wen)(wen)壓(ya)管(guan)正(zheng)向導通時電壓(ya)均為(wei)0.7V，則(ze)串(chuan)(chuan)聯(lian)后(hou)共有四種(zhong)不同(tong)的穩(wen)(wen)(wen)(wen)(wen)壓(ya)值，如圖(tu)1示。
6、穩壓(ya)(ya)管一(yi)般(ban)不并聯使(shi)用。幾個(ge)(ge)穩壓(ya)(ya)管并聯后(hou)，穩壓(ya)(ya)值(zhi)將由(you)最低(包括正向(xiang)導通后(hou)的(de)電壓(ya)(ya)值(zhi))的(de)一(yi)個(ge)(ge)來決(jue)定(ding)。還是以上(shang)述兩個(ge)(ge)穩壓(ya)(ya)管為(wei)例(li)，來說明穩壓(ya)(ya)值(zhi)的(de)計算方法(fa)。兩個(ge)(ge)并聯后(hou)共有四種情(qing)(qing)況(kuang)，穩壓(ya)(ya)值(zhi)只(zhi)有兩個(ge)(ge)。除非(fei)特(te)殊情(qing)(qing)況(kuang)，穩壓(ya)(ya)二極管都不并聯使(shi)用。
