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二极管简介

二极(ji)(ji)管，（英语：Diode），电子元件(jian)当中，一种具(ju)有(you)两(liang)个电极(ji)(ji)的装置(zhi)，只允许电流(liu)由(you)单(dan)一方向(xiang)流(liu)过，许多(duo)的使用(yong)是应(ying)用(yong)其整流(liu)的功(gong)能(neng)。而变容二极(ji)(ji)管（Varicap Diode）则用(yong)来当作电子式的可调电容器。大(da)部分二极(ji)(ji)管所具(ju)备的电流(liu)方向(xiang)性我们通常称(cheng)之为(wei)“整流(liu)（Rectifying）”功(gong)能(neng)。二极(ji)(ji)管最普遍的功(gong)能(neng)就是只允许电流(liu)由(you)单(dan)一方向(xiang)通过（称(cheng)为(wei)顺向(xiang)偏压(ya)），反(fan)向(xiang)时阻断(duan) （称(cheng)为(wei)逆(ni)向(xiang)偏压(ya)）。因(yin)此，二极(ji)(ji)管可以想(xiang)成电子版的逆(ni)止阀。

早(zao)期(qi)的(de)(de)(de)(de)真(zhen)空(kong)电(dian)(dian)(dian)(dian)子二(er)极(ji)管；它是一(yi)(yi)种(zhong)能够单(dan)向传导(dao)电(dian)(dian)(dian)(dian)流(liu)的(de)(de)(de)(de)电(dian)(dian)(dian)(dian)子器件。在半导(dao)体二(er)极(ji)管内部(bu)有一(yi)(yi)个(ge)PN结(jie)两个(ge)引(yin)线端子，这种(zhong)电(dian)(dian)(dian)(dian)子器件按照外加电(dian)(dian)(dian)(dian)压的(de)(de)(de)(de)方向，具(ju)备单(dan)向电(dian)(dian)(dian)(dian)流(liu)的(de)(de)(de)(de)传导(dao)性。一(yi)(yi)般来讲(jiang)，晶体二(er)极(ji)管是一(yi)(yi)个(ge)由(you)p型(xing)半导(dao)体和(he)n型(xing)半导(dao)体烧结(jie)形成(cheng)的(de)(de)(de)(de)p-n结(jie)界面(mian)。在其界面(mian)的(de)(de)(de)(de)两侧形成(cheng)空(kong)间电(dian)(dian)(dian)(dian)荷层，构成(cheng)自建电(dian)(dian)(dian)(dian)场(chang)。当外加电(dian)(dian)(dian)(dian)压等于零时，由(you)于p-n 结(jie)两边载流(liu)子的(de)(de)(de)(de)浓度差引(yin)起扩散(san)电(dian)(dian)(dian)(dian)流(liu)和(he)由(you)自建电(dian)(dian)(dian)(dian)场(chang)引(yin)起的(de)(de)(de)(de)漂(piao)移电(dian)(dian)(dian)(dian)流(liu)相等而处于电(dian)(dian)(dian)(dian)平衡状(zhuang)态(tai)，这也是常态(tai)下的(de)(de)(de)(de)二(er)极(ji)管特性。

二极管检测维修实战

稳(wen)压二(er)极管主(zhu)(zhu)要用在(zai)电(dian)源供路板中(zhong)，的可以(yi)采(cai)开(kai)测(ce)量(liang)(liang)也 稳(wen)压二(er)极管主(zhu)(zhu)要用在(zai)电(dian)源供路板中(zhong)，的可以(yi)采(cai)开(kai)测(ce)量(liang)(liang)也 稳(wen)压二(er)极管主(zhu)(zhu)要用在(zai)电(dian)源供路板中(zhong)，的可以(yi)采(cai)开(kai)测(ce)量(liang)(liang)也 可以(yi)采(cai)用在(zai)路测(ce)量(liang)(liang)。

（1）首先(xian)将待(dai)测稳(wen)压(ya)二(er)(er)极(ji)管(guan)(guan)的电源(yuan)断开，接(jie)着对(dui)待(dai)测稳(wen)压(ya)二(er)(er)极(ji)管(guan)(guan)进行观察，看待(dai)测稳(wen) 压(ya)二(er)(er)极(ji)管(guan)(guan)是否损(sun)(sun)坏(huai)(huai)，有无烧焦、虚焊等情(qing)况。如果有，稳(wen)压(ya)二(er)(er)极(ji)管(guan)(guan)已损(sun)(sun)坏(huai)(huai)。本(ben)次待(dai)测的稳(wen)压(ya)二(er)(er)极(ji)管(guan)(guan)如图1所示(shi)，外(wai)形完好没有明显的物理损(sun)(sun)坏(huai)(huai)。

（2）为使(shi)测(ce)量(liang)(liang)的(de)结果更加准确，用(yong)(yong)一小毛刷清洁稳压二极管的(de)两端，去除两端引脚下 的(de)污物，如图2所示(shi)。避免因油污的(de)隔(ge)离(li)作(zuo)用(yong)(yong)使(shi)表笔与引脚间的(de)接触不实影响测(ce)量(liang)(liang)结果。

（3）清洁完毕(bi)后选择数字(zi)万用表的“二极(ji)管”挡，如(ru)图3所示。

（4）将数字万用表的两表笔分别接待测稳(wen)压二(er)极管的两极，如图4所(suo)示(shi)。测出一固 定阻值。

（5）交换两表笔再测一次如图5所示。发现读数(shu)为(wei)无穷大。

两次(ci)检(jian)测(ce)(ce)中出现固定电阻的(de)那一(yi)(yi)组的(de)接(jie)法即为(wei)正(zheng)向(xiang)接(jie)法（红表笔(bi)所(suo)接(jie)的(de)为(wei)万(wan)用表得正(zheng) 极），经检(jian)测(ce)(ce)待测(ce)(ce)稳(wen)压二极管(guan)正(zheng)向(xiang)电阻为(wei)一(yi)(yi)固定电阻值，反向(xiang)电阻为(wei)无穷大。因此该稳(wen)压二 极管(guan)的(de)功能(neng)基本正(zheng)常。

如(ru)果(guo)待(dai)测(ce)稳压(ya)二极(ji)(ji)(ji)管(guan)(guan)的正(zheng)向(xiang)阻值(zhi)(zhi)和(he)反向(xiang)阻值(zhi)(zhi)均为无穷(qiong)大，则二极(ji)(ji)(ji)管(guan)(guan)很可能有断路故障；如(ru)果(guo)测(ce)得(de)稳压(ya)二极(ji)(ji)(ji)管(guan)(guan)正(zheng)向(xiang)阻值(zhi)(zhi)和(he)反向(xiang)阻值(zhi)(zhi)都接近(jin)于0，则二极(ji)(ji)(ji)管(guan)(guan)已(yi)被击穿短路；如(ru)果(guo)测(ce)得(de)稳 压(ya)二极(ji)(ji)(ji)管(guan)(guan)正(zheng)向(xiang)阻值(zhi)(zhi)和(he)反向(xiang)阻值(zhi)(zhi)相(xiang)差不大，则说明二极(ji)(ji)(ji)管(guan)(guan)已(yi)经失去了单(dan)向(xiang)导电(dian)性或单(dan)向(xiang)导电(dian)性不良(liang)。

二极管工作原理

晶(jing)体二(er)极管为一(yi)个由p型半导体和(he)n型半导体形成的(de)(de)pn结，在(zai)(zai)其界(jie)面处两(liang)侧形成空(kong)间电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)层(ceng)(ceng)，并建有(you)(you)自建电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)场(chang)(chang)(chang)。当(dang)不(bu)存(cun)在(zai)(zai)外(wai)加电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)时，由于(yu)pn结两(liang)边载流(liu)(liu)(liu)子(zi)浓(nong)度(du)差引起的(de)(de)扩(kuo)散电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)和(he)自建电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)场(chang)(chang)(chang)引起的(de)(de)漂移电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)相等而处于(yu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)平衡状态。当(dang)外(wai)界(jie)有(you)(you)正向(xiang)(xiang)(xiang)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)偏置时，外(wai)界(jie)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)场(chang)(chang)(chang)和(he)自建电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)场(chang)(chang)(chang)的(de)(de)互相抑消(xiao)作(zuo)用使载流(liu)(liu)(liu)子(zi)的(de)(de)扩(kuo)散电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)增(zeng)加引起了正向(xiang)(xiang)(xiang)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)。当(dang)外(wai)界(jie)有(you)(you)反向(xiang)(xiang)(xiang)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)偏置时，外(wai)界(jie)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)场(chang)(chang)(chang)和(he)自建电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)场(chang)(chang)(chang)进一(yi)步加强，形成在(zai)(zai)一(yi)定反向(xiang)(xiang)(xiang)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)范围内与(yu)反向(xiang)(xiang)(xiang)偏置电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)值(zhi)无关(guan)的(de)(de)反向(xiang)(xiang)(xiang)饱(bao)和(he)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)I0。当(dang)外(wai)加的(de)(de)反向(xiang)(xiang)(xiang)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)高到一(yi)定程度(du)时，pn结空(kong)间电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)层(ceng)(ceng)中(zhong)的(de)(de)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)场(chang)(chang)(chang)强度(du)达(da)到临(lin)界(jie)值(zhi)产(chan)生载流(liu)(liu)(liu)子(zi)的(de)(de)倍增(zeng)过程，产(chan)生大量(liang)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)空(kong)穴对，产(chan)生了数值(zhi)很大的(de)(de)反向(xiang)(xiang)(xiang)击(ji)穿(chuan)(chuan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)，称为二(er)极管的(de)(de)击(ji)穿(chuan)(chuan)现象(xiang)。pn结的(de)(de)反向(xiang)(xiang)(xiang)击(ji)穿(chuan)(chuan)有(you)(you)齐纳击(ji)穿(chuan)(chuan)和(he)雪崩(beng)击(ji)穿(chuan)(chuan)之分。

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