利盈娱乐(中国)创新平台有限公司

恒流(liu)源原理与作用(yong)

一：原理
恒(heng)(heng)(heng)流(liu)(liu)(liu)亦可(ke)叫(jiao)稳(wen)流(liu)(liu)(liu)，意思相近，一般可(ke)以不(bu)加区别。与(yu)恒(heng)(heng)(heng)压(ya)(ya)(ya)的(de)(de)概(gai)(gai)念(nian)(nian)相比，恒(heng)(heng)(heng)流(liu)(liu)(liu)的(de)(de)概(gai)(gai)念(nian)(nian)就难于(yu)理解(jie)一些了，因为日常(chang)生活中恒(heng)(heng)(heng)压(ya)(ya)(ya)源(yuan)是(shi)多见的(de)(de)，蓄电(dian)(dian)池(chi)、干电(dian)(dian)池(chi)是(shi)直流(liu)(liu)(liu)恒(heng)(heng)(heng)压(ya)(ya)(ya) 电(dian)(dian)源(yuan)，而 220V 交流(liu)(liu)(liu)电(dian)(dian)，则(ze)可(ke)认为是(shi)一种交流(liu)(liu)(liu)恒(heng)(heng)(heng)压(ya)(ya)(ya)电(dian)(dian)源(yuan)，因为它们的(de)(de)输(shu)出(chu)电(dian)(dian)压(ya)(ya)(ya)是(shi)基本不(bu)变的(de)(de)，是(shi)不(bu)随(sui)输(shu)出(chu)电(dian)(dian)流(liu)(liu)(liu)的(de)(de)大小(xiao)而大幅变化的(de)(de)。

二(er)：作用(yong)与(yu)结(jie)构

恒(heng)(heng)流(liu)源(yuan),是一种(zhong)(zhong)能(neng)向负载(zai)提(ti)供恒(heng)(heng)定(ding)电(dian)(dian)(dian)流(liu)的电(dian)(dian)(dian)源(yuan)装置(zhi)，它在外界(jie)电(dian)(dian)(dian)网(wang)电(dian)(dian)(dian)源(yuan)产(chan)生(sheng)波动和(he)阻抗(kang)特性发生(sheng)变化时仍(reng)能(neng)使输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)流(liu)保(bao)持(chi)恒(heng)(heng)定(ding)。恒(heng)(heng)流(liu)源(yuan)电(dian)(dian)(dian)路(lu)(lu)具有输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)流(liu)恒(heng)(heng)定(ding)、温度(du)稳定(ding)性好(hao)、直流(liu)电(dian)(dian)(dian)阻很小但等效交流(liu)输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)阻却很大(da)等特点(dian)。恒(heng)(heng)流(liu)范围(wei)大(da)致为1μA～20A。它既可(ke)以(yi)为各种(zhong)(zhong)放大(da)电(dian)(dian)(dian)路(lu)(lu)提(ti)供偏流(liu)以(yi)稳定(ding)其静态工(gong)作(zuo)点(dian),又(you)可(ke)以(yi)作(zuo)为其有源(yuan)负载(zai),以(yi)提(ti)高放大(da)倍(bei)数。 并且在差动放大(da)电(dian)(dian)(dian)路(lu)(lu)、脉冲产(chan)生(sheng)电(dian)(dian)(dian)路(lu)(lu)中也得到了广泛应用。依(yi)据其主要构(gou)成元件可(ke)以(yi)分为以(yi)下(xia)几种(zhong)(zhong)。

（1）晶体管(guan)恒流源(yuan)

这类恒流源以晶体三极管为主(zhu)要组成器件(jian),利用(yong)(yong)晶(jing)体三极(ji)管(guan)集(ji)电(dian)(dian)极(ji)电(dian)(dian)压变化对电(dian)(dian)流(liu)影响小,并在电(dian)(dian)路(lu)中采用(yong)(yong)电(dian)(dian)流(liu)负反馈来(lai)提高输(shu)出(chu)电(dian)(dian)流(liu)的(de)(de)恒定性，如图12-4。由晶(jing)体管(guan)构成的(de)(de)恒流(liu)源,广泛(fan)地用(yong)(yong)作差动放大器的(de)(de)射极(ji)公共(gong)电(dian)(dian)阻,或作为放大电(dian)(dian)路(lu)的(de)(de)有源负载,或作为偏流(liu)使用(yong)(yong),也可以作为脉冲产生电(dian)(dian)路(lu)的(de)(de)充(chong)放电(dian)(dian)电(dian)(dian)流(liu),由于(yu)晶(jing)体管(guan)参数受温度变化影响,大多采用(yong)(yong)了温度补偿及(ji)稳压措施(shi),或增强电(dian)(dian)流(liu)负反馈的(de)(de)深度以进(jin)一(yi)步稳定输(shu)出(chu)电(dian)(dian)流(liu)。

（2）场(chang)效应管恒(heng)流源

其基本电(dian)(dian)路与晶(jing)体(ti)管(guan)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)类似。场效(xiao)应(ying)管(guan)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)较(jiao)(jiao)之晶(jing)体(ti)管(guan)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan),其等效(xiao)内阻(zu)较(jiao)(jiao)小(xiao),但增大(da)电(dian)(dian)流(liu)(liu)负反馈电(dian)(dian)阻(zu),场效(xiao)应(ying)管(guan)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)会取得更好的效(xiao)果。且无需辅(fu)助电(dian)(dian)源(yuan)(yuan),是一个(ge)纯两端网络,这(zhei)种工作方式十分有用,可以用来代(dai)替任意一个(ge)欧姆(mu)电(dian)(dian)阻(zu)。 通常,将(jiang)场效(xiao)应(ying)和(he)晶(jing)体(ti)管(guan)配合使用,其恒(heng)(heng)流(liu)(liu)效(xiao)果会更佳。

（3）集成运放恒流源

由于温度对集成运放参数影响不如对晶体管或场效应管参数影响之(zhi)显著,由集成(cheng)(cheng)运放构成(cheng)(cheng)的恒(heng)流源(yuan)具有稳定性更好,恒(heng)流性能更高(gao)的优(you)点。 尤其在(zai)负(fu)载一端需接地,要求大电流的场合,获得(de)了广泛应用。

联系方式：邹先生

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