穩壓(ya)二極管工(gong)作在(zai)(zai)反向擊(ji)穿狀態時(shi)，其兩端的電(dian)壓(ya)是基本不(bu)變的。利(li)用(yong)這一性質，在(zai)(zai)電(dian)路里常(chang)用(yong)于(yu)構成穩壓(ya)電(dian)路。
穩(wen)壓(ya)二極(ji)管構成的(de)穩(wen)壓(ya)電路，雖然穩(wen)定度不很高，但卻具有(you)簡(jian)單、經濟實用的(de)優(you)點，因(yin)而應用非常廣(guang)泛(fan)。
在實際電路中(zhong)，要使用好穩壓二極管，應注意如下幾個問題。
1、要注意一般二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)與穩(wen)壓(ya)(ya)二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)區別(bie)方法(fa)。不少的(de)(de)(de)(de)一般二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)，特別(bie)是(shi)玻璃封裝的(de)(de)(de)(de)管(guan)(guan)(guan)，外(wai)形(xing)顏色等與穩(wen)壓(ya)(ya)二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)較(jiao)相似，如不細心區別(bie)，就會(hui)使用錯誤。區別(bie)方法(fa)是(shi)：看外(wai)形(xing)，不少穩(wen)壓(ya)(ya)二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)為(wei)園(yuan)柱(zhu)形(xing)，較(jiao)短(duan)粗，而一般二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)若為(wei)園(yuan)柱(zhu)形(xing)的(de)(de)(de)(de)則較(jiao)細長；看標(biao)志(zhi)，穩(wen) 壓(ya)(ya)二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)外(wai)表(biao)(biao)面(mian)上都標(biao)有穩(wen)壓(ya)(ya)值(zhi)，如5V6，表(biao)(biao)示穩(wen)壓(ya)(ya)值(zhi)為(wei)5.6V；用萬用表(biao)(biao)進行(xing)測量，根據(ju)單向導電性(xing)(xing)，用X1K擋(dang)(dang)先把(ba)被測二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)正負極(ji)(ji)(ji)性(xing)(xing)判斷出來，然后(hou)用X10K擋(dang)(dang)，黑表(biao)(biao)筆接二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)負極(ji)(ji)(ji)，紅表(biao)(biao)筆接二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)正極(ji)(ji)(ji)，測的(de)(de)(de)(de)阻值(zhi)與X1K擋(dang)(dang)時(shi)相比，若出現(xian)的(de)(de)(de)(de)反(fan)向阻值(zhi)很大，為(wei)一般二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)可能性(xing)(xing)很大，若出現(xian)的(de)(de)(de)(de)反(fan)向阻值(zhi)變(bian)得很小，則為(wei)穩(wen)壓(ya)(ya)二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)。
2、注(zhu)意穩(wen)(wen)(wen)壓(ya)(ya)(ya)二極管(guan)(guan)(guan)正向(xiang)(xiang)(xiang)(xiang)(xiang)使(shi)(shi)用(yong)(yong)與反向(xiang)(xiang)(xiang)(xiang)(xiang)使(shi)(shi)用(yong)(yong)的區別。穩(wen)(wen)(wen)壓(ya)(ya)(ya)二極管(guan)(guan)(guan)正向(xiang)(xiang)(xiang)(xiang)(xiang)導通(tong)使(shi)(shi)用(yong)(yong)時(shi)(shi)，與一(yi)般二極管(guan)(guan)(guan)正向(xiang)(xiang)(xiang)(xiang)(xiang)導通(tong)使(shi)(shi)用(yong)(yong)時(shi)(shi)基(ji)本相同(tong)，正向(xiang)(xiang)(xiang)(xiang)(xiang)導通(tong)后兩(liang)端電壓(ya)(ya)(ya)也(ye)是(shi)基(ji)本不變的，都約為0.7V。從理論上(shang)講，穩(wen)(wen)(wen)壓(ya)(ya)(ya)二極管(guan)(guan)(guan)也(ye)可(ke)正向(xiang)(xiang)(xiang)(xiang)(xiang)使(shi)(shi)用(yong)(yong)做(zuo)穩(wen)(wen)(wen)壓(ya)(ya)(ya)管(guan)(guan)(guan)用(yong)(yong)，但其穩(wen)(wen)(wen)壓(ya)(ya)(ya)值(zhi)將(jiang)低于1V，且穩(wen)(wen)(wen)壓(ya)(ya)(ya)性能也(ye)不好，一(yi)般不單(dan)獨(du)用(yong)(yong)穩(wen)(wen)(wen)壓(ya)(ya)(ya)管(guan)(guan)(guan)的正向(xiang)(xiang)(xiang)(xiang)(xiang)導通(tong)特(te)性來穩(wen)(wen)(wen)壓(ya)(ya)(ya)，而是(shi)用(yong)(yong)反向(xiang)(xiang)(xiang)(xiang)(xiang)擊穿(chuan)特(te)性來穩(wen)(wen)(wen)壓(ya)(ya)(ya)。反向(xiang)(xiang)(xiang)(xiang)(xiang)擊穿(chuan)電壓(ya)(ya)(ya)值(zhi)即為穩(wen)(wen)(wen)壓(ya)(ya)(ya)值(zhi)。有(you)時(shi)(shi)將(jiang)兩(liang)個穩(wen)(wen)(wen)壓(ya)(ya)(ya)管(guan)(guan)(guan)串聯使(shi)(shi)用(yong)(yong)，一(yi)個利(li)用(yong)(yong)它(ta)的正向(xiang)(xiang)(xiang)(xiang)(xiang)特(te)性，另一(yi)個利(li)用(yong)(yong)它(ta)的反向(xiang)(xiang)(xiang)(xiang)(xiang)特(te)性，則(ze)既能穩(wen)(wen)(wen)壓(ya)(ya)(ya)又可(ke)起溫度補償作用(yong)(yong)，以提高穩(wen)(wen)(wen)壓(ya)(ya)(ya)效(xiao)果。
3、要(yao)注意限流(liu)(liu)電(dian)阻(zu)(zu)(zu)的(de)(de)作用(yong)及阻(zu)(zu)(zu)值大小的(de)(de)影響。在穩壓(ya)(ya)二極(ji)管(guan)穩壓(ya)(ya)電(dian)路中(zhong)，一(yi)般都(dou)要(yao)串接一(yi)個電(dian)阻(zu)(zu)(zu)R，如圖(tu)1或(huo)2示。該電(dian)阻(zu)(zu)(zu)在電(dian)路中(zhong)起限流(liu)(liu)和提高穩壓(ya)(ya)效果的(de)(de)作用(yong)。若不加該電(dian)阻(zu)(zu)(zu)即當(dang)R=0時，容易燒壞(huai)穩壓(ya)(ya)管(guan)，穩壓(ya)(ya)效果也會極(ji)差。限流(liu)(liu)電(dian)阻(zu)(zu)(zu)的(de)(de)阻(zu)(zu)(zu)值越大，電(dian)路穩壓(ya)(ya)性能越好(hao)，但(dan)輸入與輸出壓(ya)(ya)差也會過(guo)大，耗電(dian)也就越多。
4、要注(zhu)意輸入與(yu)輸出(chu)的壓(ya)(ya)差。正(zheng)常使用時(shi)，穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)二(er)極管穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)電(dian)路(lu)的輸出(chu)電(dian)壓(ya)(ya)等于穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)管反向(xiang)擊穿后兩端的穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)值，若(ruo)輸入到(dao)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)電(dian)路(lu)中的電(dian)壓(ya)(ya)值小于穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)管的穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)值，則電(dian)路(lu)將失去穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)作(zuo)用，只有是(shi)大(da)(da)于關(guan)系時(shi)，才有穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)作(zuo)用，并且(qie)壓(ya)(ya)差越大(da)(da)，限流電(dian)阻的阻值也應(ying)越大(da)(da)，否則會損壞穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)管。
5、穩(wen)壓(ya)(ya)(ya)管(guan)可串聯(lian)使(shi)用。幾個(ge)穩(wen)壓(ya)(ya)(ya)管(guan)串聯(lian)后，可獲得(de)多個(ge)不同(tong)的穩(wen)壓(ya)(ya)(ya)值(zhi)(zhi)，故串聯(lian)使(shi)用較常(chang)見。下面(mian)舉例說明(ming)兩個(ge)穩(wen)壓(ya)(ya)(ya)管(guan)串聯(lian)使(shi)用后，如何求得(de)穩(wen)壓(ya)(ya)(ya)值(zhi)(zhi)。若一個(ge)穩(wen)壓(ya)(ya)(ya)管(guan)的穩(wen)壓(ya)(ya)(ya)值(zhi)(zhi)為5.6V，另一個(ge)穩(wen)壓(ya)(ya)(ya)值(zhi)(zhi)為3.6V，設穩(wen)壓(ya)(ya)(ya)管(guan)正向導通時電(dian)壓(ya)(ya)(ya)均為0.7V，則串聯(lian)后共有四種(zhong)不同(tong)的穩(wen)壓(ya)(ya)(ya)值(zhi)(zhi)，如圖(tu)1示。
6、穩(wen)壓(ya)管(guan)一般不并聯(lian)使用。幾(ji)個(ge)(ge)穩(wen)壓(ya)管(guan)并聯(lian)后(hou)，穩(wen)壓(ya)值(zhi)將由最低(di)(包括正向導通后(hou)的電壓(ya)值(zhi))的一個(ge)(ge)來(lai)決定。還是以上述兩(liang)個(ge)(ge)穩(wen)壓(ya)管(guan)為例，來(lai)說明穩(wen)壓(ya)值(zhi)的計算方(fang)法。兩(liang)個(ge)(ge)并聯(lian)后(hou)共有(you)四種(zhong)情(qing)況(kuang)，穩(wen)壓(ya)值(zhi)只有(you)兩(liang)個(ge)(ge)。除非特殊情(qing)況(kuang)，穩(wen)壓(ya)二極管(guan)都不并聯(lian)使用。
