login_新博2「一家高质量的游戏平台」什么二叫极管正向压降？

什(shen)么(me)叫二极管正向压降？

信息来源：本站　日期：2017-04-06　

分(fen)享到(dao)：

在电路中，电流(liu)只能从二(er)极(ji)(ji)管的正极(ji)(ji)流(liu)入(ru)，负极(ji)(ji)流(liu)出。在规(gui)定的正向电流(liu)下，二(er)极(ji)(ji)管的正向电压(ya)降，是(shi)二(er)极(ji)(ji)管能够(gou)导(dao)通的正向最低电压(ya)。在下面通过简单的实验说(shuo)明二(er)极(ji)(ji)管的正向特(te)性和反向特(te)性。

1. 反向特性。

在电(dian)(dian)(dian)(dian)子电(dian)(dian)(dian)(dian)路中(zhong)，二(er)(er)极(ji)管(guan)的正极(ji)接(jie)在低电(dian)(dian)(dian)(dian)位(wei)端，负极(ji)接(jie)在高电(dian)(dian)(dian)(dian)位(wei)端，此时(shi)二(er)(er)极(ji)管(guan)中(zhong)几乎没有电(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)流(liu)(liu)(liu)(liu)过，此时(shi)二(er)(er)极(ji)管(guan)处(chu)于截(jie)止状(zhuang)态，这(zhei)种连接(jie)方式，称为(wei)反(fan)(fan)向偏(pian)置(zhi)。二(er)(er)极(ji)管(guan)处(chu)于反(fan)(fan)向偏(pian)置(zhi)时(shi)，仍然会(hui)有微弱的反(fan)(fan)向电(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)流(liu)(liu)(liu)(liu)过二(er)(er)极(ji)管(guan)，称为(wei)漏电(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)。当二(er)(er)极(ji)管(guan)两端的反(fan)(fan)向电(dian)(dian)(dian)(dian)压(ya)增大(da)到某一(yi)数值，反(fan)(fan)向电(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)会(hui)急剧增大(da)，二(er)(er)极(ji)管(guan)将失(shi)去(qu)单方向导(dao)电(dian)(dian)(dian)(dian)特性，这(zhei)种状(zhuang)态称为(wei)二(er)(er)极(ji)管(guan)的击穿。

2. 正向特(te)性。

在(zai)电(dian)(dian)(dian)子(zi)电(dian)(dian)(dian)路中(zhong)，将二(er)极(ji)(ji)管(guan)(guan)(guan)的正(zheng)极(ji)(ji)接在(zai)高(gao)电(dian)(dian)(dian)位(wei)端(duan)(duan)，负极(ji)(ji)接在(zai)低(di)电(dian)(dian)(dian)位(wei)端(duan)(duan)，二(er)极(ji)(ji)管(guan)(guan)(guan)就会导(dao)(dao)通(tong)(tong)，这种连接方(fang)式，称为(wei)正(zheng)向(xiang)(xiang)偏置。必须说明，当加在(zai)二(er)极(ji)(ji)管(guan)(guan)(guan)两端(duan)(duan)的正(zheng)向(xiang)(xiang)电(dian)(dian)(dian)压(ya)(ya)(ya)很小时，二(er)极(ji)(ji)管(guan)(guan)(guan)仍然(ran)不能导(dao)(dao)通(tong)(tong)，流(liu)过二(er)极(ji)(ji)管(guan)(guan)(guan)的正(zheng)向(xiang)(xiang)电(dian)(dian)(dian)流(liu)十分(fen)微(wei)弱。只(zhi)有当正(zheng)向(xiang)(xiang)电(dian)(dian)(dian)压(ya)(ya)(ya)达到某一(yi)(yi)数值（这一(yi)(yi)数值称为(wei)“门槛电(dian)(dian)(dian)压(ya)(ya)(ya)”，锗管(guan)(guan)(guan)约(yue)(yue)为(wei)0.2V，硅管(guan)(guan)(guan)约(yue)(yue)为(wei)0.6V）以后，二(er)极(ji)(ji)管(guan)(guan)(guan)才能直正(zheng)导(dao)(dao)通(tong)(tong)。导(dao)(dao)通(tong)(tong)后二(er)极(ji)(ji)管(guan)(guan)(guan)两端(duan)(duan)的电(dian)(dian)(dian)压(ya)(ya)(ya)基本上(shang)保持不变（锗管(guan)(guan)(guan)约(yue)(yue)为(wei)0.3V，硅管(guan)(guan)(guan)约(yue)(yue)为(wei)0.7V），称为(wei)二(er)极(ji)(ji)管(guan)(guan)(guan)的“正(zheng)向(xiang)(xiang)压(ya)(ya)(ya)降”。

小电(dian)流硅二极管的(de)正(zheng)向压降，在中(zhong)等电(dian)流水平(ping)下，约(yue)0.6～0.8V；锗(zhe)二极管约(yue)0.2～0.3 V。大功率的(de)硅二极管的(de)正(zheng)向压降往(wang)往(wang)达到1V。