二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)主要(yao)特(te)性(xing)就(jiu)是(shi)(shi)單向(xiang)導(dao)電(dian)(dian)(dian)(dian)(dian)(dian)。可(ke)用(yong)于：檢波、整流(liu)、穩(wen)壓(ya)(ya)(ya)、隔離反(fan)向(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)；另有(you)發(fa)(fa)光(guang)(guang)(guang)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)、阻(zu)尼二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)、光(guang)(guang)(guang)敏(min)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)、壓(ya)(ya)(ya)敏(min)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)、氣敏(min)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)等(deng)等(deng)專用(yong)半導(dao)體器(qi)件。 1、作(zuo)(zuo)用(yong)：二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)主要(yao)特(te)性(xing)是(shi)(shi)單向(xiang)導(dao)電(dian)(dian)(dian)(dian)(dian)(dian)性(xing)，也就(jiu)是(shi)(shi)在(zai)(zai)正向(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)的(de)(de)(de)(de)作(zuo)(zuo)用(yong)下(xia)，導(dao)通(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)很小；而在(zai)(zai)反(fan)向(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)作(zuo)(zuo)用(yong)下(xia)導(dao)通(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)極(ji)(ji)(ji)(ji)(ji)(ji)大(da)(da)或(huo)無窮大(da)(da)。正因為(wei)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)具(ju)有(you)上(shang)述(shu)特(te)性(xing)，無繩電(dian)(dian)(dian)(dian)(dian)(dian)話(hua)機(ji)中常把(ba)它(ta)用(yong)在(zai)(zai)整流(liu)、隔離、穩(wen)壓(ya)(ya)(ya)、極(ji)(ji)(ji)(ji)(ji)(ji)性(xing)保(bao)(bao)(bao)護、編(bian)碼(ma)控制(zhi)(zhi)、調(diao)頻調(diao)制(zhi)(zhi)和靜噪等(deng)電(dian)(dian)(dian)(dian)(dian)(dian)路中。晶體二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)按作(zuo)(zuo)用(yong)可(ke)分(fen)為(wei)：整流(liu)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)（如1N4004）、隔離二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)（如1N4148）、肖特(te)基二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)（如BAT85）、發(fa)(fa)光(guang)(guang)(guang)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)、穩(wen)壓(ya)(ya)(ya)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)等(deng) 2、穩(wen)壓(ya)(ya)(ya)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)穩(wen)壓(ya)(ya)(ya)原理：穩(wen)壓(ya)(ya)(ya)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)特(te)點就(jiu)是(shi)(shi)擊穿后，其(qi)兩端的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)基本(ben)保(bao)(bao)(bao)持不變。這樣(yang)，當把(ba)穩(wen)壓(ya)(ya)(ya)管(guan)(guan)(guan)接(jie)(jie)入電(dian)(dian)(dian)(dian)(dian)(dian)路以(yi)(yi)后，若由(you)于電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)發(fa)(fa)生波動(dong)，或(huo)其(qi)它(ta)原因造成電(dian)(dian)(dian)(dian)(dian)(dian)路中各點電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)變動(dong)時(shi)，負(fu)載兩端的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)將基本(ben)保(bao)(bao)(bao)持不變 3.變容(rong)(rong)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)是(shi)(shi)根據普通(tong)(tong)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)內(nei)部 “PN結” 的(de)(de)(de)(de)結電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)能(neng)(neng)隨外(wai)加反(fan)向(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)的(de)(de)(de)(de)變化(hua)而變化(hua)這一(yi)原理專門(men)設(she)計出來的(de)(de)(de)(de)一(yi)種(zhong)特(te)殊(shu)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)。 變容(rong)(rong)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)在(zai)(zai)無繩電(dian)(dian)(dian)(dian)(dian)(dian)話(hua)機(ji)中主要(yao)用(yong)在(zai)(zai)手(shou)機(ji)或(huo)座(zuo)機(ji)的(de)(de)(de)(de)高(gao)頻調(diao)制(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)路上(shang)，實現低頻信號調(diao)制(zhi)(zhi)到高(gao)頻信號上(shang)，并發(fa)(fa)射(she)出去。在(zai)(zai)工作(zuo)(zuo)狀(zhuang)態，變容(rong)(rong)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)調(diao)制(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)一(yi)般加到負(fu)極(ji)(ji)(ji)(ji)(ji)(ji)上(shang)，使變容(rong)(rong)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)內(nei)部結電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)容(rong)(rong)量隨調(diao)制(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)的(de)(de)(de)(de)變化(hua)而變化(hua) 4.光(guang)(guang)(guang)電(dian)(dian)(dian)(dian)(dian)(dian)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)（LED） 光(guang)(guang)(guang)電(dian)(dian)(dian)(dian)(dian)(dian)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)、光(guang)(guang)(guang)電(dian)(dian)(dian)(dian)(dian)(dian)三(san)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)是(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)子電(dian)(dian)(dian)(dian)(dian)(dian)路中廣泛(fan)采(cai)用(yong)的(de)(de)(de)(de)光(guang)(guang)(guang)敏(min)器(qi)件。光(guang)(guang)(guang)電(dian)(dian)(dian)(dian)(dian)(dian)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)和普通(tong)(tong)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)一(yi)樣(yang)具(ju)有(you)一(yi)個PN結，不同之處是(shi)(shi)在(zai)(zai)光(guang)(guang)(guang)電(dian)(dian)(dian)(dian)(dian)(dian)二(er)(er)(er)(er)(er)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)外(wai)殼(ke)上(shang)有(you)一(yi)個透明的(de)(de)(de)(de)窗口以(yi)(yi)接(jie)(jie)收光(guang)(guang)(guang)線照射(she)，實現光(guang)(guang)(guang)電(dian)(dian)(dian)(dian)(dian)(dian)轉換，在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)路圖中文(wen)字符(fu)號一(yi)般為(wei)VD。光(guang)(guang)(guang)電(dian)(dian)(dian)(dian)(dian)(dian)三(san)極(ji)(ji)(ji)(ji)(ji)(ji)管(guan)(guan)(guan)除具(ju)有(you)光(guang)(guang)(guang)電(dian)(dian)(dian)(dian)(dian)(dian)轉換的(de)(de)(de)(de)功(gong)能(neng)(neng)外(wai)，還具(ju)有(you)放大(da)(da)功(gong)能(neng)(neng)，在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)路圖中文(wen)字符(fu)號一(yi)般為(wei)VT。