【二(er)(er)極(ji)管的作用(yong)(yong)】二(er)(er)極(ji)管在(zai)電路中(zhong)有什么作用(yong)(yong) 二(er)(er)極(ji)管的特性有哪(na)些

二極管在電路中有什么作用

二極管是電子元件當中(zhong)一(yi)種具有兩個(ge)電(dian)(dian)極的裝(zhuang)置，只允許(xu)電(dian)(dian)流(liu)由(you)(you)單(dan)一(yi)方(fang)向流(liu)過，許(xu)多的使用是(shi)應用其整(zheng)流(liu)的功(gong)能(neng)。而變容二(er)極管(guan)(guan)則用來當作電(dian)(dian)子式的可(ke)(ke)調(diao)電(dian)(dian)容器。大部(bu)分二(er)極管(guan)(guan)所具備(bei)的電(dian)(dian)流(liu)方(fang)向性(xing)我們通常稱(cheng)之(zhi)為“整(zheng)流(liu)”功(gong)能(neng)。二(er)極管(guan)(guan)最普遍的功(gong)能(neng)就是(shi)只允許(xu)電(dian)(dian)流(liu)由(you)(you)單(dan)一(yi)方(fang)向通過（稱(cheng)為順向偏(pian)壓），反向時阻斷 （稱(cheng)為逆向偏(pian)壓）。因(yin)此(ci)，二(er)極管(guan)(guan)可(ke)(ke)以(yi)想成電(dian)(dian)子版的逆止閥。

該圖片由注冊用戶"橘子de殿堂"提供，版權聲明反饋

二極管是最常用的電子元件之一，它最大的特性就是單向導電，也就是電流只可以從二極管的一個方向流過，二極管的作用有整流電路，檢波電路，穩壓電路，各種調制電路，主要都是由二極管來構成的，其原理都很簡單，正是由于二極管等元件的發明，才有我們現在豐富多彩的電子信息世界的誕生，既然二極管的作用這么大那么我們應該如何去檢測這個元件呢，其實很簡單只要用萬用表打到電阻檔測量一下反向電阻如果很小就說明這個二極管是(shi)壞的(de)，反向電阻如果(guo)很大(da)這就說明這個二極管是(shi)好的(de)。

二極管的特性有哪些

正向性

外加正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)時，在正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)特性的(de)(de)(de)(de)起(qi)始部(bu)分，正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)很(hen)小(xiao)，不(bu)足以(yi)克服PN結(jie)內電(dian)(dian)(dian)(dian)場的(de)(de)(de)(de)阻擋(dang)作(zuo)用，正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)電(dian)(dian)(dian)(dian)流(liu)幾(ji)乎為(wei)(wei)(wei)零，這一段稱為(wei)(wei)(wei)死區。這個不(bu)能使(shi)二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)導通(tong)的(de)(de)(de)(de)正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)稱為(wei)(wei)(wei)死區電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)。當正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)大于死區電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)以(yi)后，PN結(jie)內電(dian)(dian)(dian)(dian)場被(bei)克服，二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)導通(tong)，電(dian)(dian)(dian)(dian)流(liu)隨電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)增大而迅(xun)速上(shang)升。在正(zheng)(zheng)(zheng)常使(shi)用的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)流(liu)范圍內，導通(tong)時二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)端(duan)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)幾(ji)乎維持不(bu)變，這個電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)稱為(wei)(wei)(wei)二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)。當二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)兩端(duan)的(de)(de)(de)(de)正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)超過一定數(shu)值，內電(dian)(dian)(dian)(dian)場很(hen)快(kuai)被(bei)削弱，特性電(dian)(dian)(dian)(dian)流(liu)迅(xun)速增長，二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)導通(tong)。叫做門坎電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)或閾值電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)，硅管(guan)(guan)(guan)約為(wei)(wei)(wei)0.5V，鍺管(guan)(guan)(guan)約為(wei)(wei)(wei)0.1V。硅二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)導通(tong)壓(ya)(ya)(ya)(ya)(ya)降約為(wei)(wei)(wei)0.6~0.8V，鍺二(er)(er)(er)極(ji)(ji)(ji)管(guan)(guan)(guan)的(de)(de)(de)(de)正(zheng)(zheng)(zheng)向(xiang)(xiang)(xiang)導通(tong)壓(ya)(ya)(ya)(ya)(ya)降約為(wei)(wei)(wei)0.2~0.3V。

反向性

外加反向電壓不超過一定范圍時，通過二極管的電流是少數載流子漂移運動所形成反向電流。由于反向電流很小，二極管處(chu)于截(jie)止狀(zhuang)態。這個反(fan)向(xiang)(xiang)電流(liu)(liu)(liu)又稱為(wei)反(fan)向(xiang)(xiang)飽(bao)和(he)電流(liu)(liu)(liu)或(huo)漏電流(liu)(liu)(liu)，二極(ji)管(guan)(guan)(guan)的(de)反(fan)向(xiang)(xiang)飽(bao)和(he)電流(liu)(liu)(liu)受溫度(du)(du)影響很大。一般硅管(guan)(guan)(guan)的(de)反(fan)向(xiang)(xiang)電流(liu)(liu)(liu)比鍺管(guan)(guan)(guan)小(xiao)得多，小(xiao)功率硅管(guan)(guan)(guan)的(de)反(fan)向(xiang)(xiang)飽(bao)和(he)電流(liu)(liu)(liu)在nA數(shu)量級，小(xiao)功率鍺管(guan)(guan)(guan)在μA數(shu)量級。溫度(du)(du)升高時，半(ban)導體受熱激發，少(shao)數(shu)載流(liu)(liu)(liu)子數(shu)目增加，反(fan)向(xiang)(xiang)飽(bao)和(he)電流(liu)(liu)(liu)也隨之增加。

反向擊穿

齊納擊穿

反向擊(ji)穿(chuan)(chuan)(chuan)(chuan)按機理(li)分(fen)為齊納擊(ji)穿(chuan)(chuan)(chuan)(chuan)和雪崩擊(ji)穿(chuan)(chuan)(chuan)(chuan)兩種(zhong)(zhong)情(qing)況。在高摻雜濃度(du)(du)的情(qing)況下，因勢壘(lei)區(qu)寬(kuan)(kuan)(kuan)度(du)(du)很小，反向電(dian)(dian)壓(ya)較(jiao)大時，破(po)壞了勢壘(lei)區(qu)內共價(jia)鍵(jian)結構(gou)，使價(jia)電(dian)(dian)子(zi)脫離共價(jia)鍵(jian)束縛(fu)，產(chan)(chan)生電(dian)(dian)子(zi)-空穴對，致使電(dian)(dian)流急劇增大，這(zhe)種(zhong)(zhong)擊(ji)穿(chuan)(chuan)(chuan)(chuan)稱(cheng)為齊納擊(ji)穿(chuan)(chuan)(chuan)(chuan)。如果摻雜濃度(du)(du)較(jiao)低，勢壘(lei)區(qu)寬(kuan)(kuan)(kuan)度(du)(du)較(jiao)寬(kuan)(kuan)(kuan)，不(bu)容易產(chan)(chan)生齊納擊(ji)穿(chuan)(chuan)(chuan)(chuan)。

雪崩擊穿

另一種(zhong)(zhong)擊穿為(wei)雪(xue)(xue)崩擊穿。當反向電(dian)(dian)壓增加(jia)(jia)到較大(da)數值(zhi)時，外加(jia)(jia)電(dian)(dian)場使電(dian)(dian)子漂移速度加(jia)(jia)快，從而與共(gong)價(jia)鍵中(zhong)的價(jia)電(dian)(dian)子相碰撞，把價(jia)電(dian)(dian)子撞出共(gong)價(jia)鍵，產生新的電(dian)(dian)子-空穴對(dui)。新產生的電(dian)(dian)子-空穴被電(dian)(dian)場加(jia)(jia)速后又撞出其它價(jia)電(dian)(dian)子，載流(liu)(liu)子雪(xue)(xue)崩式地(di)增加(jia)(jia)，致使電(dian)(dian)流(liu)(liu)急劇增加(jia)(jia)，這種(zhong)(zhong)擊穿稱為(wei)雪(xue)(xue)崩擊穿。無(wu)論(lun)哪種(zhong)(zhong)擊穿，若(ruo)對(dui)其電(dian)(dian)流(liu)(liu)不加(jia)(jia)限制(zhi)，都(dou)可能(neng)造成PN結(jie)永久性損壞。