电源电路(lu)图组成及作(zuo)用(yong) 电源电路(lu)要诀讲解及工作(zuo)原理 KIA MOS管(guan)
信息(xi)来源：本站 日期：2018-04-24
当初学者面对(dui)有几十(shi)乃(nai)至几百个元(yuan)器件的电路图(tu)，并且它们的连(lian)线(xian)纵(zong)横(heng)交叉，形式变化多端，往往会不知道(dao)所措， 如何(he)才能轻松(song)地读懂它们呢?
其实(shi)电(dian)(dian)子电(dian)(dian)路本身有很强的(de)(de)规律性，不管多复杂的(de)(de)电(dian)(dian)路，经(jing)过(guo)分(fen)析可(ke)以发现，它(ta)是(shi)(shi)由少数几(ji)个(ge)单元(yuan)电(dian)(dian)路组(zu)成(cheng)的(de)(de)。就像(xiang)小孩子们玩的(de)(de)积(ji)木，虽然只有十来种(zhong)或二三十种(zhong)块(kuai)块(kuai)，可(ke)是(shi)(shi)在孩子们手中却可(ke)以搭成(cheng)几(ji)十乃(nai)至几(ji)百种(zhong)平面图形或立(li)体(ti)模型(xing)。同理，再复杂的(de)(de)电(dian)(dian)路，经(jing)过(guo)分(fen)析就可(ke)发现，它(ta)也是(shi)(shi)由少数几(ji)个(ge)单元(yuan)电(dian)(dian)路组(zu)成(cheng)的(de)(de)。因此初学(xue)(xue)者只要先熟(shu)悉常用的(de)(de)基本单元(yuan)电(dian)(dian)路，再学(xue)(xue)会分(fen)析和(he)分(fen)解电(dian)(dian)路的(de)(de)本领，就事半(ban)功(gong)倍了。
按单(dan)元电(dian)路(lu)的功能(neng)可以把它们(men)分(fen)成若(ruo)干类，每一类又有(you)(you)好多种，全(quan)部单(dan)元电(dian)路(lu)大概总有(you)(you)几百种。下面我(wo)们(men)选最常用的基本单(dan)元电(dian)路(lu)来介绍(shao)。让我(wo)们(men)从电(dian)源电(dian)路(lu)开始。
电(dian)(dian)(dian)(dian)源(yuan)是将其它形式(shi)的能(neng)转(zhuan)换成(cheng)电(dian)(dian)(dian)(dian)能(neng)的装(zhuang)置。发电(dian)(dian)(dian)(dian)机能(neng)把机械能(neng)转(zhuan)换成(cheng)电(dian)(dian)(dian)(dian)能(neng)，干电(dian)(dian)(dian)(dian)池能(neng)把化学能(neng)转(zhuan)换成(cheng)电(dian)(dian)(dian)(dian)能(neng)。发电(dian)(dian)(dian)(dian)机、电(dian)(dian)(dian)(dian)池本(ben)身并(bing)不带电(dian)(dian)(dian)(dian)，它的两(liang)极(ji)分(fen)别(bie)有(you)正(zheng)负(fu)电(dian)(dian)(dian)(dian)荷，由正(zheng)负(fu)电(dian)(dian)(dian)(dian)荷产(chan)生电(dian)(dian)(dian)(dian)压(ya)（电(dian)(dian)(dian)(dian)流是电(dian)(dian)(dian)(dian)荷在电(dian)(dian)(dian)(dian)压(ya)的作(zuo)用下定向移(yi)动(dong)而(er)形成(cheng)的），电(dian)(dian)(dian)(dian)荷导体里本(ben)来(lai)就(jiu)有(you)，要产(chan)生电(dian)(dian)(dian)(dian)流只需要加上(shang)电(dian)(dian)(dian)(dian)压(ya)即可(ke)，当电(dian)(dian)(dian)(dian)池两(liang)极(ji)接上(shang)导体时为(wei)了(le)产(chan)生电(dian)(dian)(dian)(dian)流而(er)把正(zheng)负(fu)电(dian)(dian)(dian)(dian)荷释(shi)放出去，当电(dian)(dian)(dian)(dian)荷散尽时，也(ye)就(jiu)荷尽流（压(ya)）消(xiao)了(le)。干电(dian)(dian)(dian)(dian)池等叫做(zuo)(zuo)电(dian)(dian)(dian)(dian)源(yuan)。通过变压(ya)器和整流器，把交流电(dian)(dian)(dian)(dian)变成(cheng)直流电(dian)(dian)(dian)(dian)的装(zhuang)置叫做(zuo)(zuo)整流电(dian)(dian)(dian)(dian)源(yuan)。能(neng)提供信(xin)号的电(dian)(dian)(dian)(dian)子设备叫做(zuo)(zuo)信(xin)号源(yuan)。整流电(dian)(dian)(dian)(dian)源(yuan)、信(xin)号源(yuan)有(you)时也(ye)叫做(zuo)(zuo)电(dian)(dian)(dian)(dian)源(yuan)。
普(pu)通(tong)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)又可细分为：开关(guan)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、逆变(bian)(bian)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、交流稳压(ya)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、直流稳压(ya)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、DC/DC电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、通(tong)信电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、模(mo)块电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、变(bian)(bian)频电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、UPS电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、EPS应急电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、净化电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、PC电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、整流电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、定制电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、加热电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、焊接(jie)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)/电(dian)(dian)(dian)(dian)(dian)弧电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、电(dian)(dian)(dian)(dian)(dian)镀电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、网络电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、电(dian)(dian)(dian)(dian)(dian)力操作电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、适配器(qi)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、线性电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)控制器(qi)/驱动(dong)器(qi)、功率(lv)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、其他普(pu)通(tong)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、逆变(bian)(bian)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、参(can)数电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、调压(ya)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)、变(bian)(bian)压(ya)器(qi)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)。
电源(yuan)，分为交(jiao)流和(he)直(zhi)(zhi)流，常用(yong)英文字母(mu)AC（交(jiao)流）和(he)DC（直(zhi)(zhi)流）表示(shi)。
电(dian)(dian)(dian)(dian)(dian)压，也称作(zuo)电(dian)(dian)(dian)(dian)(dian)势(shi)差(cha)或电(dian)(dian)(dian)(dian)(dian)位(wei)差(cha)，是衡(heng)量(liang)单位(wei)电(dian)(dian)(dian)(dian)(dian)荷在静电(dian)(dian)(dian)(dian)(dian)场中(zhong)由于(yu)电(dian)(dian)(dian)(dian)(dian)势(shi)不(bu)同所产生(sheng)的(de)能量(liang)差(cha)的(de)物理量(liang)。其大(da)小等(deng)于(yu)单位(wei)正电(dian)(dian)(dian)(dian)(dian)荷因受电(dian)(dian)(dian)(dian)(dian)场力作(zuo)用(yong)从A点移动到B点所做(zuo)的(de)功，电(dian)(dian)(dian)(dian)(dian)压的(de)方向规定(ding)为(wei)从高电(dian)(dian)(dian)(dian)(dian)位(wei)指(zhi)向低电(dian)(dian)(dian)(dian)(dian)位(wei)的(de)方向。电(dian)(dian)(dian)(dian)(dian)压的(de)国(guo)际单位(wei)制为(wei)伏(fu)(fu)特(te)（V，简称伏(fu)(fu)），常用(yong)的(de)单位(wei)还有(you)毫伏(fu)(fu)（mV）、微伏(fu)(fu)（μV）、千伏(fu)(fu)（kV）等(deng)。此概念与水位(wei)高低所造成的(de)“水压”相(xiang)似(si)。需(xu)要指(zhi)出的(de)是，“电(dian)(dian)(dian)(dian)(dian)压”一词一般只用(yong)于(yu)电(dian)(dian)(dian)(dian)(dian)路(lu)当(dang)中(zhong)，“电(dian)(dian)(dian)(dian)(dian)势(shi)差(cha)”和“电(dian)(dian)(dian)(dian)(dian)位(wei)差(cha)”则普遍应用(yong)于(yu)一切电(dian)(dian)(dian)(dian)(dian)现象当(dang)中(zhong)。
每个电(dian)(dian)(dian)子设备都有一个供给能(neng)量的(de)电(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)路。电(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)路有整流(liu)(liu)(liu)电(dian)(dian)(dian)源(yuan)、逆变电(dian)(dian)(dian)源(yuan)和(he)变频器三种。常(chang)见的(de)家用(yong)(yong)电(dian)(dian)(dian)器中多数(shu)要用(yong)(yong)到直(zhi)流(liu)(liu)(liu)电(dian)(dian)(dian)源(yuan)。直(zhi)流(liu)(liu)(liu)电(dian)(dian)(dian)源(yuan)的(de)最简单的(de)供电(dian)(dian)(dian)方法是(shi)用(yong)(yong)电(dian)(dian)(dian)池(chi)。但电(dian)(dian)(dian)池(chi)有成本高、体(ti)积大、需要不时(shi)更换（蓄电(dian)(dian)(dian)池(chi)则(ze)要经(jing)常(chang)充电(dian)(dian)(dian)）的(de)缺点(dian)，因(yin)此最经(jing)济可(ke)靠(kao)而又方便的(de)是(shi)使用(yong)(yong)整流(liu)(liu)(liu)电(dian)(dian)(dian)源(yuan)。
电(dian)(dian)(dian)(dian)(dian)(dian)(dian) 子电(dian)(dian)(dian)(dian)(dian)(dian)(dian)路中的电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)一(yi)般是低压直(zhi)(zhi)流(liu)(liu)(liu)(liu)(liu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)，所以(yi)要想从(cong) 220 伏市(shi)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)变换成(cheng)直(zhi)(zhi)流(liu)(liu)(liu)(liu)(liu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)，应该先把 220伏交流(liu)(liu)(liu)(liu)(liu)变成(cheng)低压交流(liu)(liu)(liu)(liu)(liu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)，再用整流(liu)(liu)(liu)(liu)(liu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)路变成(cheng)脉动(dong)(dong)的直(zhi)(zhi)流(liu)(liu)(liu)(liu)(liu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)，最后(hou)用滤波电(dian)(dian)(dian)(dian)(dian)(dian)(dian)路滤除脉动(dong)(dong)直(zhi)(zhi)流(liu)(liu)(liu)(liu)(liu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)中的交流(liu)(liu)(liu)(liu)(liu)成(cheng)分(fen)后(hou)才能得到直(zhi)(zhi)流(liu)(liu)(liu)(liu)(liu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)。有的电(dian)(dian)(dian)(dian)(dian)(dian)(dian)子设(she)备对电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)的质量要求很高，所以(yi)有时(shi)还需要再增加一(yi)个(ge)稳压电(dian)(dian)(dian)(dian)(dian)(dian)(dian)路。因(yin)此整流(liu)(liu)(liu)(liu)(liu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)的组成(cheng)一(yi)般有四大(da)部分(fen)，见图 1 。其中变压电(dian)(dian)(dian)(dian)(dian)(dian)(dian)路其实就是一(yi)个(ge)铁芯变压器，需要介绍的只是后(hou)面三种单元电(dian)(dian)(dian)(dian)(dian)(dian)(dian)路。
整流电(dian)(dian)(dian)路(lu)(lu)是利用半导(dao)体二极管的(de)单向导(dao)电(dian)(dian)(dian)性能把交流电(dian)(dian)(dian)变成单向脉(mai)动直流电(dian)(dian)(dian)的(de)电(dian)(dian)(dian)路(lu)(lu)。
（ 1 ）半波整流
半波整流电(dian)(dian)(dian)路只需一个二极管，见图 2 （ a ）。在(zai)交流电(dian)(dian)(dian)正半周(zhou)时(shi) VD 导通，负(fu)半周(zhou)时(shi) VD 截止，负(fu)载 R 上得到的是(shi)脉动的直流电(dian)(dian)(dian)
（ 2 ）全波整流
全波(bo)整流(liu)要用(yong)两个二极管，而且(qie)要求变压(ya)器有带中心抽(chou)头的两个圈数相同(tong)的次(ci)级线(xian)圈，见(jian)图 2 （ b ）。负载 R L 上得到的是(shi)脉动的全波(bo)整流(liu)电流(liu)，输出电压(ya)比(bi)半波(bo)整流(liu)电路高。
（ 3 ）全波桥式整流
用(yong) 4 个二极管(guan)组(zu)成的桥式整流电路(lu)可以(yi)使用(yong)只有(you)单个次级线圈的变压(ya)器，见图 2 （ c ）。负载上的电流波形和(he)输出电压(ya)值与全波整流电路(lu)相同。
（ 4 ）倍压整流
用多个(ge)二极管和(he) 电(dian)容器可以获(huo)得较(jiao)高的直流(liu)电(dian)压(ya)(ya)。图 2 （ d ）是一(yi)个(ge)二倍压(ya)(ya)整(zheng)流(liu)电(dian)路(lu)。当 U2 为(wei)负(fu)半周时(shi) VD1 导(dao)通(tong)， C1 被充(chong)电(dian)， C1 上最高电(dian)压(ya)(ya)可接(jie)近(jin) 1.4U2 ；当 U2 正半周时(shi)VD2 导(dao)通(tong)， C1 上的电(dian)压(ya)(ya)和(he) U2 叠加在一(yi)起对 C2 充(chong)电(dian)，使 C2 上电(dian)压(ya)(ya)接(jie)近(jin)2.8U2 ，是 C1 上电(dian)压(ya)(ya)的 2 倍，所以叫(jiao)倍压(ya)(ya)整(zheng)流(liu)电(dian)路(lu)。
整流(liu)(liu)后(hou)得到的(de)(de)是脉动直(zhi)(zhi)流(liu)(liu)电，如果加上(shang)滤(lv)波(bo)电路滤(lv)除脉动直(zhi)(zhi)流(liu)(liu)电中(zhong)的(de)(de)交流(liu)(liu)成分(fen)，就(jiu)可(ke)得到平(ping)滑(hua)的(de)(de)直(zhi)(zhi)流(liu)(liu)电。
（ 1 ）电容滤波
把电容(rong)器和负载(zai)并联，如图 3 （ a ），正半周时电容(rong)被充电，负半周时电容(rong)放电，就可(ke)使负载(zai)上得到平滑的直流电。
（ 2 ）电感滤波
把电(dian)感和负载串联(lian)起来，如图 3 （ b ），也能滤除脉动电(dian)流(liu)中的交(jiao)流(liu)成(cheng)分(fen)。
（ 3 ） L、 C 滤波
用 1 个(ge)(ge)(ge)电(dian)(dian)感(gan)和(he) 1 个(ge)(ge)(ge)电(dian)(dian)容组成的滤(lv)波电(dian)(dian)路因(yin)为象(xiang)一个(ge)(ge)(ge)倒写的字母“ L ”，被称为 L 型，见(jian)图 3 （ c ）。用 1 个(ge)(ge)(ge)电(dian)(dian)感(gan)和(he) 2 个(ge)(ge)(ge)电(dian)(dian)容的滤(lv)波电(dian)(dian)路因(yin)为象(xiang)字母“ π ”，被称为 π 型，见(jian)图 3 （ d ），这是滤(lv)波效果较(jiao)好的电(dian)(dian)路。
（ 4 ）RC 滤波
电(dian)感(gan)(gan)器的成(cheng)本高(gao)、体积大，所以在电(dian)流(liu)不太大的电(dian)子电(dian)路中常(chang)用(yong)电(dian)阻(zu)器取代电(dian)感(gan)(gan)器而(er)组成(cheng) RC 滤波电(dian)路。同样(yang)，它也有 L 型，见图(tu) 3 （ e ）； π 型，见图(tu) 3 （ f ）。
交流(liu)电网电压的(de)(de)波(bo)动(dong)(dong)和(he)负载电流(liu)的(de)(de)变(bian)化都(dou)会使整流(liu)电源的(de)(de)输出电压和(he)电流(liu)随(sui)之(zhi)变(bian)动(dong)(dong)，因此要求较高的(de)(de)电子电路(lu)必须使用稳压电源。
用一(yi)个稳压(ya)(ya)(ya)(ya)管和(he)负(fu)载并联的电路(lu)是最(zui)简单的稳压(ya)(ya)(ya)(ya)电路(lu)，见图 4 （ a ）。图中 R 是限(xian)流电阻。这个电路(lu)的输出电流很小，它的输出电压(ya)(ya)(ya)(ya)等于稳压(ya)(ya)(ya)(ya)管的稳定电压(ya)(ya)(ya)(ya)值 V Z 。
有放大和负反馈作用的(de)(de)串联型(xing)(xing)稳压(ya)电(dian)(dian)(dian)(dian)(dian)路(lu)(lu)是(shi)(shi)最(zui)常用的(de)(de)稳压(ya)电(dian)(dian)(dian)(dian)(dian)路(lu)(lu)。它(ta)的(de)(de)电(dian)(dian)(dian)(dian)(dian)路(lu)(lu)和框(kuang)图见图 4 （ b ）、（ c ）。它(ta)是(shi)(shi)从取样电(dian)(dian)(dian)(dian)(dian)路(lu)(lu)（R3 、 R4 ）中(zhong)检测出(chu)(chu)输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)(dian)(dian)压(ya)的(de)(de)变动，与基准电(dian)(dian)(dian)(dian)(dian)压(ya)（ V Z）比较并经放大器（ VT2 ）放大后加到调(diao)(diao)整管(guan)(guan)（ VT1 ）上(shang)，使(shi)调(diao)(diao)整管(guan)(guan)两端的(de)(de)电(dian)(dian)(dian)(dian)(dian)压(ya)随着变化(hua)。如果(guo)(guo)输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)(dian)(dian)压(ya)下降(jiang)(jiang)，就(jiu)使(shi)调(diao)(diao)整管(guan)(guan)管(guan)(guan)压(ya)降(jiang)(jiang)也(ye)降(jiang)(jiang)低，于(yu)是(shi)(shi)输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)(dian)(dian)压(ya)被(bei)提升(sheng)；如果(guo)(guo)输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)(dian)(dian)压(ya)上(shang)升(sheng)，就(jiu)使(shi)调(diao)(diao)整管(guan)(guan)管(guan)(guan)压(ya)降(jiang)(jiang)也(ye)上(shang)升(sheng)，于(yu)是(shi)(shi)输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)(dian)(dian)压(ya)被(bei)压(ya)低，结果(guo)(guo)就(jiu)使(shi)输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)(dian)(dian)压(ya)基本不变。在这个电(dian)(dian)(dian)(dian)(dian)路(lu)(lu)的(de)(de)基础上(shang)发展成很多变型(xing)(xing)电(dian)(dian)(dian)(dian)(dian)路(lu)(lu)或(huo)增(zeng)(zeng)加一些辅(fu)助电(dian)(dian)(dian)(dian)(dian)路(lu)(lu)，如用复(fu)合(he)管(guan)(guan)作调(diao)(diao)整管(guan)(guan)，输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)(dian)(dian)压(ya)可(ke)调(diao)(diao)的(de)(de)电(dian)(dian)(dian)(dian)(dian)路(lu)(lu)，用运算放 大器作比较放大的(de)(de)电(dian)(dian)(dian)(dian)(dian)路(lu)(lu)，以及增(zeng)(zeng)加辅(fu)助电(dian)(dian)(dian)(dian)(dian)源和过流保(bao)护电(dian)(dian)(dian)(dian)(dian)路(lu)(lu)等。
近(jin)年来广泛应用的新型稳压电源是开关(guan)型稳压电源。它的调整管工作在开关(guan)状(zhuang)态，本(ben)身功耗很小，所以(yi)有效率高、体积(ji)小等优点，但电路(lu)比较(jiao)复杂。
开(kai)关(guan)稳压电(dian)源从原(yuan)理上分有很多种(zhong)。它的基本原(yuan)理框图(tu)见(jian)图(tu) 4 （ d ）。图(tu)中(zhong)电(dian)感 L 和电(dian)容(rong) C 是储能和滤(lv)波元件(jian)，二极(ji)管(guan)(guan) VD 是调整管(guan)(guan)在关(guan)断状态时(shi)为 L 、 C滤(lv)波器提供电(dian)流通(tong)路的续流二极(ji)管(guan)(guan)。开(kai)关(guan)稳压电(dian)源的开(kai)关(guan)频率都很高，一般为几～几十千(qian)赫(he)，所以(yi)电(dian)感器的体积不很大，输(shu)出电(dian)压中(zhong)的高次谐波也不多。
它的(de)基本工作原理是 : 从取样电(dian)(dian)路（ R3 、 R4 ）中(zhong)检测出(chu)取样电(dian)(dian)压(ya)(ya)经比较放大后去控制一个矩形波(bo)(bo)发生(sheng)器。矩形波(bo)(bo)发生(sheng)器的(de)输出(chu)脉(mai)冲是控制调整管（ VT ）的(de)导(dao)(dao)通(tong)和(he)截(jie)止时间的(de)。如果输出(chu)电(dian)(dian)压(ya)(ya) U 0 因为电(dian)(dian)网电(dian)(dian)压(ya)(ya)或负载电(dian)(dian)流的(de)变(bian)(bian)动而降低，就会使(shi)矩形波(bo)(bo)发生(sheng)器的(de)输出(chu)脉(mai)冲变(bian)(bian)宽(kuan)，于是调整管导(dao)(dao)通(tong)时间增大，使(shi) L 、 C 储能(neng)电(dian)(dian)路得到(dao)更(geng)多的(de)能(neng)量，结(jie)果是使(shi)输出(chu)电(dian)(dian)压(ya)(ya) U 0 被提升，达(da)到(dao)了稳定输出(chu)电(dian)(dian)压(ya)(ya)的(de)目的(de)。
近年(nian)来已有(you)大量(liang)集成稳(wen)压器产品(pin)问世，品(pin)种很多(duo)，结(jie)构(gou)也各(ge)不(bu)相同。目前用得(de)较多(duo)的(de)有(you)三(san)端集成稳(wen)压器，有(you)输(shu)出正电压的(de)CW7800 系(xi)列和输(shu)出负(fu)电压的(de) CW7900 系(xi)列等产品(pin)。输(shu)出电流从 0.1A ～ 3A ，输(shu)出电压有(you) 5V、 6V 、 9V 、 12V 、 15V 、 18V 、 24V 等多(duo)种。
这种集成稳压器只(zhi)有(you)三(san)个端子，稳压电路的所有(you)部(bu)分包括大功率(lv)调整管以及保(bao)护电路等都已集成在芯片内。使用时只(zhi)要加上(shang)散热片后接到整流滤波电路后面就(jiu)行了。外围元件少，稳压精度(du)高，工作可(ke)靠(kao)，一(yi)般不(bu)需调试。
图 4 （ e ）是(shi)一个三端(duan)稳(wen)压器电(dian)路。图中 C 是(shi)主滤(lv)波电(dian)容， C1 、 C2 是(shi)消除寄(ji)生振荡(dang)的(de)电(dian)容 ,VD 是(shi)为防止输入短路烧坏集成块而(er)使用的(de)保护二极(ji)管。
电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)是电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)中比较简(jian)单(dan)然(ran)而却是应用最广的(de)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)。拿到(dao)(dao)一张电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)图时(shi)(shi)，应该： ① 先(xian)按“整流 — 滤波 — 稳(wen)(wen)压(ya)”的(de)次序把整个(ge)(ge)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)分(fen)(fen)(fen)解(jie)开(kai)来，逐级(ji)细细分(fen)(fen)(fen)析。 ② 逐级(ji)分(fen)(fen)(fen)析时(shi)(shi)要(yao)分(fen)(fen)(fen)清主(zhu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)和(he)(he)辅助电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)、主(zhu)要(yao)元件和(he)(he)次要(yao)元件，弄清它们的(de)作用和(he)(he)参数(shu)要(yao)求(qiu)等(deng)。例如开(kai)关稳(wen)(wen)压(ya)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)中，电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)感(gan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容和(he)(he)续流二(er)极(ji)(ji)管(guan)就(jiu)是它的(de)关键元件。 ③ 因(yin)为晶体管(guan)有 NPN 和(he)(he) PNP 型两类，某些(xie)集成电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)要(yao)求(qiu)双(shuang)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)供电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，所以一个(ge)(ge)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)往往包括有不同(tong)极(ji)(ji)性(xing)不同(tong)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)值(zhi)和(he)(he)好几组(zu)输(shu)出。读(du)图时(shi)(shi)必须(xu)分(fen)(fen)(fen)清各组(zu)输(shu)出电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)的(de)数(shu)值(zhi)和(he)(he)极(ji)(ji)性(xing)。在(zai)组(zu)装(zhuang)和(he)(he)维修时(shi)(shi)也要(yao)仔细分(fen)(fen)(fen)清晶体管(guan)和(he)(he)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)解(jie)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容的(de)极(ji)(ji)性(xing)，防止出错。 ④ 熟(shu)悉某些(xie)习惯画(hua)法和(he)(he)简(jian)化画(hua)法。 ⑤ 最后(hou)把整个(ge)(ge)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)从前到(dao)(dao)后(hou)全面(mian)综合贯通起(qi)来。这张电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)图也就(jiu)读(du)懂了。
例 1 电热毯控温电路
图 5 是(shi)一个电热毯(tan)电路。开关(guan)在“ 1 ”的(de)位置是(shi)低温(wen)档。 220 伏(fu)市(shi)(shi)电经二极管后接(jie)到电热毯(tan)，因(yin)为是(shi)半波整流(liu)(liu)，电热毯(tan)两端所加(jia)的(de)是(shi)约 100 伏(fu)的(de)脉动(dong)直(zhi)流(liu)(liu)电，发热不高(gao)，所以(yi)是(shi)保(bao)温(wen)或(huo)低温(wen)状态。开关(guan)扳(ban)到“ 2 ”的(de)位置， 220 伏(fu)市(shi)(shi)电直(zhi)接(jie)接(jie)到电热毯(tan)上，所以(yi)是(shi)高(gao)温(wen)档。
例 2 高压电子灭蚊蝇器
图 6 是利用(yong)倍(bei)压整流原理得到(dao)小电(dian)(dian)(dian)(dian)流直流高压电(dian)(dian)(dian)(dian)的灭蚊蝇(ying)器。 220伏交流经过(guo)四(si)倍(bei)压整流后(hou)输出电(dian)(dian)(dian)(dian)压可(ke)达 1100 伏，把这(zhei)个直流高压加到(dao)平行的金属丝网(wang)(wang)(wang)上。网(wang)(wang)(wang)下放诱饵，当苍蝇(ying)停在网(wang)(wang)(wang)上时(shi)造成短路(lu)，电(dian)(dian)(dian)(dian)容(rong)器上的高压通过(guo)苍蝇(ying)身体(ti)放电(dian)(dian)(dian)(dian)把蝇(ying)击毙(bi)。苍蝇(ying)尸(shi)体(ti)落(luo)下后(hou)，电(dian)(dian)(dian)(dian)容(rong)器又被充电(dian)(dian)(dian)(dian)，电(dian)(dian)(dian)(dian)网(wang)(wang)(wang)又恢复高压。这(zhei)个高压电(dian)(dian)(dian)(dian)网(wang)(wang)(wang)电(dian)(dian)(dian)(dian)流很小，因此对人无(wu)害。
由于昆虫夜间有(you)趋光性，因此如(ru)在这电网后面(mian)放(fang)一个(ge) 3 瓦荧光灯或小(xiao)型(xing)黑光灯，就可以诱杀(sha)蚊(wen)虫和有(you)害昆虫。
例 3 实用稳压电源
图 7 是(shi)一(yi)个(ge)实(shi)用(yong)(yong)的(de)(de)稳(wen)压(ya)电(dian)(dian)(dian)(dian)源。输(shu)出电(dian)(dian)(dian)(dian)压(ya) 3 ～ 9 伏(fu)可(ke)调(diao)，输(shu)出电(dian)(dian)(dian)(dian)流最大 100 毫安。这个(ge)电(dian)(dian)(dian)(dian)路就(jiu)是(shi)串联(lian)型(xing)稳(wen)压(ya)电(dian)(dian)(dian)(dian)源电(dian)(dian)(dian)(dian)路。要注意的(de)(de)是(shi) :① 整流桥的(de)(de)画法和(he)图 2 （ c ）不同(tong)，实(shi)际上它就(jiu)是(shi)桥式整流电(dian)(dian)(dian)(dian)路。 ② 这个(ge)电(dian)(dian)(dian)(dian)路使(shi)用(yong)(yong) PNP 型(xing)锗(zhe)管(guan)(guan)，所以(yi)输(shu)出是(shi)负(fu)电(dian)(dian)(dian)(dian)压(ya)，正极(ji)(ji)接地。 ③ 用(yong)(yong)两个(ge)普通二(er)极(ji)(ji)管(guan)(guan)代(dai)替(ti)(ti)稳(wen)压(ya)管(guan)(guan)。任何二(er)极(ji)(ji)管(guan)(guan)的(de)(de)正向(xiang)压(ya)降(jiang)都是(shi)基本不变的(de)(de)，因(yin)此(ci)可(ke)用(yong)(yong)二(er)极(ji)(ji)管(guan)(guan)代(dai)替(ti)(ti)稳(wen)压(ya)管(guan)(guan)。 2AP 型(xing)二(er)极(ji)(ji)管(guan)(guan)的(de)(de)正向(xiang)压(ya)降(jiang)约(yue)是(shi) 0.3 伏(fu)， 2CP 型(xing)约(yue)是(shi) 0.7 伏(fu)， 2CZ 型(xing)约(yue)是(shi) 1 伏(fu)。图中用(yong)(yong)了两个(ge) 2CZ 二(er)极(ji)(ji)管(guan)(guan)作(zuo)基准电(dian)(dian)(dian)(dian)压(ya)。 ④ 取(qu)样电(dian)(dian)(dian)(dian)阻是(shi)一(yi)个(ge)电(dian)(dian)(dian)(dian)位(wei)器，所以(yi)输(shu)出电(dian)(dian)(dian)(dian)压(ya)是(shi)可(ke)调(diao)的(de)(de)。
直(zhi)流电源很重要(yao)，电子产品(pin)不可(ke)少，
一般组成五部分，变压(ya)、整流(liu)、滤(lv)波(bo)好，
稳压、保护在(zai)后(hou)面(mian)，输出直(zhi)流很(hen)可靠。
整流(liu)电路有两(liang)种，单相整流(liu)三相整，
单相整(zheng)流小功(gong)率，电路形式分四种(zhong)，
半波(bo)、全波(bo)与桥式，倍(bei)压整(zheng)流靠电容。
半波整(zheng)流一(yi)VD，正周(zhou)导(dao)通负周(zhou)止，
输出(chu)电压零四五，VD反压根(gen)2值，
电路简(jian)单元件(jian)少，输出直流电压低(di)。
全(quan)波(bo)VD轮(lun)流(liu)通，两(liang)个半波(bo)来合成，
输(shu)出电压零点九(jiu)，反压半(ban)波二倍整，
压(ya)高、流大、效率高，变(bian)中抽头(tou)大功用(yong)。
桥(qiao)式整流4VD，连变(bian)次级极性异，
同(tong)负(fu)一(yi)端电源正，同(tong)正一(yi)端电负(fu)极(ji)，
输出电压零点九，VD反压根2值，
率(lv)高、压高、反压低，应用(yong)广(guang)泛受人喜。
高压(ya)小流(liu)(liu)直流(liu)(liu)源，倍(bei)压(ya)整(zheng)流(liu)(liu)来(lai)实现，
N只(zhi)VD N只(zhi)C，VD整流(liu)C充电。
滤波电路去脉动，电容、电感及复用，
π型(xing)滤波分两种，感容组合(he)与阻(zu)容。
电容滤波并电容，直(zhi)流开路(lu)交流通，
电容充(chong)电又放电，输出直流(liu)波形平。
电(dian)感滤波(bo)串电(dian)感，直流(liu)导(dao)通交(jiao)流(liu)断(duan)，
电感储能又释能，输(shu)出平(ping)稳直流(liu)电。
Lc型滤(lv)波受人赞，并(bing)联(lian)电容串电感，
电容通交感通直，兼有(you)两者的(de)优(you)点。
π型滤波(bo)效(xiao)果好(hao)，两种形(xing)式要(yao)知道，
电感(gan)、阻容的组合，不同场合注意挑。
串联(lian)稳(wen)压4组成，基准、取(qu)样与调整，
还(hai)有比较放大路，流大调压广(guang)泛用。
开关电源体积小，质量轻来效率(lv)高，
家用电器(qi)采(cai)用多，故障发(fa)生(sheng)也(ye)不少，
分类方法有多种，串联应用为主要，
VT周(zhou)期开与关(guan)，开有电压(ya)关(guan)压(ya)冒，
改(gai)变(bian)脉冲占空(kong)比，实现稳压(ya)应知(zhi)道。
分立元(yuan)件较(jiao)复(fu)杂，控制还(hai)是集(ji)成好，
专用集(ji)成(cheng)品种多，逐(zhu)个(ge)了(le)解就(jiu)知晓。
联系(xi)方式：邹先生
联系电话(hua)：0755-83888366-8022
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