电源电路(lu)图组成及作用 电源电路(lu)要(yao)诀讲解及工作原(yuan)理 KIA MOS管
信息来(lai)源：本(ben)站 日期：2018-04-24
当初(chu)学者面对有几(ji)十乃(nai)至几(ji)百(bai)个元器件的电(dian)路图，并(bing)且它(ta)们(men)的连线纵横(heng)交(jiao)叉，形式(shi)变化多(duo)端，往(wang)往(wang)会不知道所措， 如(ru)何才能轻松地读懂它(ta)们(men)呢?
其实电子电路本身有很强的(de)(de)规律性，不(bu)管(guan)多复(fu)杂的(de)(de)电路，经(jing)过分(fen)析可以(yi)发(fa)(fa)现，它(ta)是由少数几个(ge)单(dan)(dan)元(yuan)(yuan)(yuan)电路组(zu)成的(de)(de)。就(jiu)(jiu)像小孩子们玩的(de)(de)积木，虽然只(zhi)有十(shi)来(lai)种(zhong)或二三十(shi)种(zhong)块块，可是在孩子们手中却(que)可以(yi)搭(da)成几十(shi)乃至几百种(zhong)平(ping)面图形或立体模型。同理(li)，再复(fu)杂的(de)(de)电路，经(jing)过分(fen)析就(jiu)(jiu)可发(fa)(fa)现，它(ta)也是由少数几个(ge)单(dan)(dan)元(yuan)(yuan)(yuan)电路组(zu)成的(de)(de)。因(yin)此初学者只(zhi)要先熟悉常用的(de)(de)基本单(dan)(dan)元(yuan)(yuan)(yuan)电路，再学会分(fen)析和分(fen)解电路的(de)(de)本领，就(jiu)(jiu)事半功倍了。
按单元(yuan)电(dian)路的(de)功(gong)能可以把它们(men)分成若干类(lei)(lei)，每一类(lei)(lei)又(you)有(you)好多种，全部单元(yuan)电(dian)路大概总有(you)几百种。下面我们(men)选最(zui)常用的(de)基本单元(yuan)电(dian)路来介绍。让我们(men)从电(dian)源电(dian)路开始。
电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)是将其它(ta)形式(shi)的(de)(de)能转换(huan)成(cheng)(cheng)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能的(de)(de)装(zhuang)置(zhi)。发(fa)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)机能把(ba)机械能转换(huan)成(cheng)(cheng)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能，干电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)能把(ba)化(hua)学能转换(huan)成(cheng)(cheng)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能。发(fa)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)机、电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)本(ben)(ben)身并不带电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，它(ta)的(de)(de)两极分别(bie)有正(zheng)负电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)，由(you)正(zheng)负电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)产生(sheng)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya)（电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)是电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)在电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya)的(de)(de)作(zuo)用下定(ding)向移动而(er)形成(cheng)(cheng)的(de)(de)），电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)导(dao)体里本(ben)(ben)来就有，要产生(sheng)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)只(zhi)需要加上(shang)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya)即可，当电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)两极接上(shang)导(dao)体时为了(le)产生(sheng)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)而(er)把(ba)正(zheng)负电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)释放出(chu)去，当电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)散尽(jin)(jin)时，也就荷(he)尽(jin)(jin)流(liu)(liu)(liu)(liu)（压(ya)(ya)(ya)(ya)）消了(le)。干电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)等叫做电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)。通过变压(ya)(ya)(ya)(ya)器和整(zheng)流(liu)(liu)(liu)(liu)器，把(ba)交流(liu)(liu)(liu)(liu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)变成(cheng)(cheng)直流(liu)(liu)(liu)(liu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)装(zhuang)置(zhi)叫做整(zheng)流(liu)(liu)(liu)(liu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)。能提供信(xin)(xin)号的(de)(de)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子设备(bei)叫做信(xin)(xin)号源(yuan)。整(zheng)流(liu)(liu)(liu)(liu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)、信(xin)(xin)号源(yuan)有时也叫做电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)。
普通电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)又(you)可细分(fen)为：开关(guan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、逆(ni)变(bian)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、交流稳压电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、直流稳压电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、DC/DC电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、通信电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、模块电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、变(bian)频电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、UPS电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、EPS应急(ji)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、净化电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、PC电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、整流电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、定制电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、加热电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、焊(han)接电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)/电(dian)(dian)(dian)(dian)(dian)(dian)(dian)弧电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、电(dian)(dian)(dian)(dian)(dian)(dian)(dian)镀(du)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、网(wang)络电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、电(dian)(dian)(dian)(dian)(dian)(dian)(dian)力操(cao)作电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、适配器(qi)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、线性电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)控(kong)制器(qi)/驱动器(qi)、功率电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、其(qi)他(ta)普通电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、逆(ni)变(bian)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、参数电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、调压电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)、变(bian)压器(qi)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)。
电源，分为交(jiao)流和直流，常用英文字母AC（交(jiao)流）和DC（直流）表(biao)示。
电(dian)(dian)(dian)(dian)(dian)(dian)压，也(ye)称(cheng)作电(dian)(dian)(dian)(dian)(dian)(dian)势差(cha)(cha)(cha)或电(dian)(dian)(dian)(dian)(dian)(dian)位(wei)差(cha)(cha)(cha)，是(shi)衡量(liang)(liang)单位(wei)电(dian)(dian)(dian)(dian)(dian)(dian)荷(he)在静(jing)电(dian)(dian)(dian)(dian)(dian)(dian)场中由于(yu)(yu)电(dian)(dian)(dian)(dian)(dian)(dian)势不同(tong)所产生的(de)能量(liang)(liang)差(cha)(cha)(cha)的(de)物理量(liang)(liang)。其大小(xiao)等于(yu)(yu)单位(wei)正电(dian)(dian)(dian)(dian)(dian)(dian)荷(he)因受电(dian)(dian)(dian)(dian)(dian)(dian)场力作用(yong)从A点移动到B点所做的(de)功，电(dian)(dian)(dian)(dian)(dian)(dian)压的(de)方(fang)向(xiang)规定为从高(gao)电(dian)(dian)(dian)(dian)(dian)(dian)位(wei)指(zhi)向(xiang)低(di)电(dian)(dian)(dian)(dian)(dian)(dian)位(wei)的(de)方(fang)向(xiang)。电(dian)(dian)(dian)(dian)(dian)(dian)压的(de)国际单位(wei)制为伏(fu)(fu)(fu)特(te)（V，简称(cheng)伏(fu)(fu)(fu)），常用(yong)的(de)单位(wei)还(hai)有毫伏(fu)(fu)(fu)（mV）、微伏(fu)(fu)(fu)（μV）、千伏(fu)(fu)(fu)（kV）等。此概念与(yu)水(shui)位(wei)高(gao)低(di)所造(zao)成的(de)“水(shui)压”相似。需要指(zhi)出(chu)的(de)是(shi)，“电(dian)(dian)(dian)(dian)(dian)(dian)压”一词一般只用(yong)于(yu)(yu)电(dian)(dian)(dian)(dian)(dian)(dian)路当(dang)中，“电(dian)(dian)(dian)(dian)(dian)(dian)势差(cha)(cha)(cha)”和“电(dian)(dian)(dian)(dian)(dian)(dian)位(wei)差(cha)(cha)(cha)”则(ze)普(pu)遍应用(yong)于(yu)(yu)一切电(dian)(dian)(dian)(dian)(dian)(dian)现象当(dang)中。
每个电(dian)(dian)(dian)子设备都有一个供(gong)给能量的(de)(de)电(dian)(dian)(dian)源(yuan)(yuan)电(dian)(dian)(dian)路。电(dian)(dian)(dian)源(yuan)(yuan)电(dian)(dian)(dian)路有整流(liu)电(dian)(dian)(dian)源(yuan)(yuan)、逆变(bian)电(dian)(dian)(dian)源(yuan)(yuan)和变(bian)频(pin)器三(san)种。常见(jian)的(de)(de)家(jia)用(yong)电(dian)(dian)(dian)器中多数要用(yong)到直流(liu)电(dian)(dian)(dian)源(yuan)(yuan)。直流(liu)电(dian)(dian)(dian)源(yuan)(yuan)的(de)(de)最简单的(de)(de)供(gong)电(dian)(dian)(dian)方法是用(yong)电(dian)(dian)(dian)池。但电(dian)(dian)(dian)池有成本高、体积(ji)大、需(xu)要不时更换（蓄电(dian)(dian)(dian)池则要经常充电(dian)(dian)(dian)）的(de)(de)缺(que)点(dian)，因(yin)此最经济可靠而又方便的(de)(de)是使(shi)用(yong)整流(liu)电(dian)(dian)(dian)源(yuan)(yuan)。
电(dian)(dian)(dian) 子(zi)(zi)电(dian)(dian)(dian)路(lu)(lu)中(zhong)的(de)(de)(de)(de)电(dian)(dian)(dian)源(yuan)一般是低压(ya)直(zhi)流(liu)(liu)(liu)电(dian)(dian)(dian)，所以(yi)要(yao)想(xiang)从 220 伏市电(dian)(dian)(dian)变(bian)(bian)(bian)换(huan)成直(zhi)流(liu)(liu)(liu)电(dian)(dian)(dian)，应(ying)该先把 220伏交(jiao)(jiao)流(liu)(liu)(liu)变(bian)(bian)(bian)成低压(ya)交(jiao)(jiao)流(liu)(liu)(liu)电(dian)(dian)(dian)，再(zai)用整(zheng)流(liu)(liu)(liu)电(dian)(dian)(dian)路(lu)(lu)变(bian)(bian)(bian)成脉(mai)动(dong)的(de)(de)(de)(de)直(zhi)流(liu)(liu)(liu)电(dian)(dian)(dian)，最后(hou)用滤波电(dian)(dian)(dian)路(lu)(lu)滤除脉(mai)动(dong)直(zhi)流(liu)(liu)(liu)电(dian)(dian)(dian)中(zhong)的(de)(de)(de)(de)交(jiao)(jiao)流(liu)(liu)(liu)成分后(hou)才能(neng)得到直(zhi)流(liu)(liu)(liu)电(dian)(dian)(dian)。有(you)的(de)(de)(de)(de)电(dian)(dian)(dian)子(zi)(zi)设备对电(dian)(dian)(dian)源(yuan)的(de)(de)(de)(de)质(zhi)量要(yao)求很高，所以(yi)有(you)时还需要(yao)再(zai)增加(jia)一个稳压(ya)电(dian)(dian)(dian)路(lu)(lu)。因(yin)此整(zheng)流(liu)(liu)(liu)电(dian)(dian)(dian)源(yuan)的(de)(de)(de)(de)组成一般有(you)四(si)大(da)部(bu)分，见图 1 。其中(zhong)变(bian)(bian)(bian)压(ya)电(dian)(dian)(dian)路(lu)(lu)其实就是一个铁(tie)芯变(bian)(bian)(bian)压(ya)器，需要(yao)介绍的(de)(de)(de)(de)只是后(hou)面(mian)三种单元电(dian)(dian)(dian)路(lu)(lu)。
整(zheng)流电路是利用半导(dao)体(ti)二(er)极管的单向(xiang)导(dao)电性能把交(jiao)流电变成单向(xiang)脉动(dong)直流电的电路。
（ 1 ）半波整流
半(ban)波整流电路只需一个二极管，见图 2 （ a ）。在(zai)交流电正(zheng)半(ban)周(zhou)时 VD 导通，负半(ban)周(zhou)时 VD 截止(zhi)，负载 R 上得到(dao)的(de)是脉(mai)动的(de)直流电
（ 2 ）全波整流
全波整(zheng)流(liu)要用两(liang)个(ge)二极管(guan)，而且要求变压器有带(dai)中心抽头的两(liang)个(ge)圈数(shu)相同的次级线圈，见图(tu) 2 （ b ）。负载 R L 上得到(dao)的是脉动的全波整(zheng)流(liu)电流(liu)，输(shu)出(chu)电压比半波整(zheng)流(liu)电路高。
（ 3 ）全波桥式整流
用 4 个二极管组成的(de)桥式整流(liu)电(dian)路可以使用只有单(dan)个次级线圈的(de)变压器，见图 2 （ c ）。负载(zai)上的(de)电(dian)流(liu)波形和(he)输出电(dian)压值(zhi)与全波整流(liu)电(dian)路相同(tong)。
（ 4 ）倍压整流
用多(duo)个二极管和 电(dian)(dian)容器(qi)可(ke)以获得(de)较高(gao)的(de)直流(liu)(liu)(liu)电(dian)(dian)压。图(tu) 2 （ d ）是(shi)一(yi)个二倍(bei)(bei)压整(zheng)流(liu)(liu)(liu)电(dian)(dian)路(lu)。当 U2 为负半周时 VD1 导通(tong)， C1 被充电(dian)(dian)， C1 上(shang)最高(gao)电(dian)(dian)压可(ke)接(jie)近 1.4U2 ；当 U2 正半周时VD2 导通(tong)， C1 上(shang)的(de)电(dian)(dian)压和 U2 叠加在一(yi)起(qi)对 C2 充电(dian)(dian)，使 C2 上(shang)电(dian)(dian)压接(jie)近2.8U2 ，是(shi) C1 上(shang)电(dian)(dian)压的(de) 2 倍(bei)(bei)，所以叫(jiao)倍(bei)(bei)压整(zheng)流(liu)(liu)(liu)电(dian)(dian)路(lu)。
整(zheng)流(liu)(liu)后(hou)得到的(de)是脉动直流(liu)(liu)电(dian)(dian)，如果加上滤波电(dian)(dian)路滤除脉动直流(liu)(liu)电(dian)(dian)中的(de)交流(liu)(liu)成分(fen)，就(jiu)可得到平滑的(de)直流(liu)(liu)电(dian)(dian)。
（ 1 ）电容滤波
把电(dian)容器和(he)负载并联(lian)，如图 3 （ a ），正半(ban)周时电(dian)容被(bei)充电(dian)，负半(ban)周时电(dian)容放电(dian)，就(jiu)可使(shi)负载上(shang)得到平(ping)滑的(de)直流电(dian)。
（ 2 ）电感滤波
把电感和(he)负载串联起来，如图 3 （ b ），也能滤(lv)除脉(mai)动电流(liu)中的交流(liu)成分(fen)。
（ 3 ） L、 C 滤波
用(yong) 1 个电(dian)(dian)(dian)感(gan)(gan)和 1 个电(dian)(dian)(dian)容组(zu)成的滤波电(dian)(dian)(dian)路因为(wei)(wei)象(xiang)一个倒写的字(zi)母“ L ”，被称为(wei)(wei) L 型(xing)，见图 3 （ c ）。用(yong) 1 个电(dian)(dian)(dian)感(gan)(gan)和 2 个电(dian)(dian)(dian)容的滤波电(dian)(dian)(dian)路因为(wei)(wei)象(xiang)字(zi)母“ π ”，被称为(wei)(wei) π 型(xing)，见图 3 （ d ），这是滤波效果(guo)较(jiao)好(hao)的电(dian)(dian)(dian)路。
（ 4 ）RC 滤波
电(dian)(dian)感(gan)器的成本高、体积大，所(suo)以在电(dian)(dian)流不太大的电(dian)(dian)子电(dian)(dian)路中常用电(dian)(dian)阻器取代电(dian)(dian)感(gan)器而组(zu)成 RC 滤波电(dian)(dian)路。同样，它也有 L 型，见图 3 （ e ）； π 型，见图 3 （ f ）。
交(jiao)流电(dian)网电(dian)压(ya)的波动和(he)负载(zai)电(dian)流的变(bian)化都会(hui)使(shi)整流电(dian)源(yuan)的输出电(dian)压(ya)和(he)电(dian)流随之变(bian)动，因此(ci)要求(qiu)较(jiao)高的电(dian)子电(dian)路必须使(shi)用(yong)稳压(ya)电(dian)源(yuan)。
用一个(ge)稳(wen)压管和负载并联的(de)电(dian)路是(shi)最简单的(de)稳(wen)压电(dian)路，见图 4 （ a ）。图中 R 是(shi)限(xian)流(liu)(liu)电(dian)阻。这个(ge)电(dian)路的(de)输出电(dian)流(liu)(liu)很小，它的(de)输出电(dian)压等(deng)于稳(wen)压管的(de)稳(wen)定电(dian)压值 V Z 。
有放大(da)和负反馈作用的(de)串联型稳压(ya)(ya)电(dian)(dian)(dian)路(lu)(lu)(lu)是(shi)最常用的(de)稳压(ya)(ya)电(dian)(dian)(dian)路(lu)(lu)(lu)。它(ta)的(de)电(dian)(dian)(dian)路(lu)(lu)(lu)和框图(tu)见图(tu) 4 （ b ）、（ c ）。它(ta)是(shi)从取样电(dian)(dian)(dian)路(lu)(lu)(lu)（R3 、 R4 ）中检测出(chu)(chu)输(shu)出(chu)(chu)电(dian)(dian)(dian)压(ya)(ya)的(de)变(bian)动(dong)，与基准电(dian)(dian)(dian)压(ya)(ya)（ V Z）比(bi)较并经放大(da)器（ VT2 ）放大(da)后加(jia)到(dao)调(diao)(diao)整(zheng)管（ VT1 ）上，使(shi)调(diao)(diao)整(zheng)管两(liang)端的(de)电(dian)(dian)(dian)压(ya)(ya)随着(zhe)变(bian)化。如果(guo)输(shu)出(chu)(chu)电(dian)(dian)(dian)压(ya)(ya)下(xia)降(jiang)(jiang)，就(jiu)使(shi)调(diao)(diao)整(zheng)管管压(ya)(ya)降(jiang)(jiang)也降(jiang)(jiang)低，于(yu)是(shi)输(shu)出(chu)(chu)电(dian)(dian)(dian)压(ya)(ya)被提升；如果(guo)输(shu)出(chu)(chu)电(dian)(dian)(dian)压(ya)(ya)上升，就(jiu)使(shi)调(diao)(diao)整(zheng)管管压(ya)(ya)降(jiang)(jiang)也上升，于(yu)是(shi)输(shu)出(chu)(chu)电(dian)(dian)(dian)压(ya)(ya)被压(ya)(ya)低，结果(guo)就(jiu)使(shi)输(shu)出(chu)(chu)电(dian)(dian)(dian)压(ya)(ya)基本不变(bian)。在(zai)这个(ge)电(dian)(dian)(dian)路(lu)(lu)(lu)的(de)基础(chu)上发展成很多变(bian)型电(dian)(dian)(dian)路(lu)(lu)(lu)或增加(jia)一(yi)些(xie)辅(fu)助(zhu)电(dian)(dian)(dian)路(lu)(lu)(lu)，如用复合管作调(diao)(diao)整(zheng)管，输(shu)出(chu)(chu)电(dian)(dian)(dian)压(ya)(ya)可调(diao)(diao)的(de)电(dian)(dian)(dian)路(lu)(lu)(lu)，用运(yun)算放 大(da)器作比(bi)较放大(da)的(de)电(dian)(dian)(dian)路(lu)(lu)(lu)，以及增加(jia)辅(fu)助(zhu)电(dian)(dian)(dian)源和过流保护电(dian)(dian)(dian)路(lu)(lu)(lu)等。
近年(nian)来(lai)广泛应用的(de)新型(xing)稳压电源是开关型(xing)稳压电源。它的(de)调(diao)整管工作在开关状(zhuang)态，本(ben)身(shen)功耗很(hen)小，所以(yi)有效率(lv)高、体积(ji)小等优点，但电路(lu)比较复(fu)杂。
开关(guan)(guan)(guan)稳(wen)压(ya)电(dian)源从原理上分有很多种。它的(de)(de)基本原理框图(tu)见图(tu) 4 （ d ）。图(tu)中(zhong)电(dian)感(gan) L 和电(dian)容 C 是储能和滤(lv)波(bo)元(yuan)件，二极(ji)管(guan) VD 是调整管(guan)在关(guan)(guan)(guan)断状态时为(wei) L 、 C滤(lv)波(bo)器(qi)提供电(dian)流通路的(de)(de)续(xu)流二极(ji)管(guan)。开关(guan)(guan)(guan)稳(wen)压(ya)电(dian)源的(de)(de)开关(guan)(guan)(guan)频率都很高，一般为(wei)几(ji)～几(ji)十千赫，所以电(dian)感(gan)器(qi)的(de)(de)体积不(bu)(bu)很大，输(shu)出电(dian)压(ya)中(zhong)的(de)(de)高次谐波(bo)也(ye)不(bu)(bu)多。
它的(de)基本(ben)工作原理(li)是(shi) : 从取样电(dian)(dian)路(lu)（ R3 、 R4 ）中(zhong)检测出取样电(dian)(dian)压(ya)经比(bi)较放大(da)后去控制一(yi)个矩形波(bo)发生(sheng)(sheng)器。矩形波(bo)发生(sheng)(sheng)器的(de)输(shu)出脉冲(chong)是(shi)控制调整管(guan)（ VT ）的(de)导通(tong)和截止时间(jian)的(de)。如果输(shu)出电(dian)(dian)压(ya) U 0 因(yin)为电(dian)(dian)网电(dian)(dian)压(ya)或负载(zai)电(dian)(dian)流的(de)变动(dong)而降低，就会使矩形波(bo)发生(sheng)(sheng)器的(de)输(shu)出脉冲(chong)变宽，于是(shi)调整管(guan)导通(tong)时间(jian)增大(da)，使 L 、 C 储能电(dian)(dian)路(lu)得到更(geng)多的(de)能量，结(jie)果是(shi)使输(shu)出电(dian)(dian)压(ya) U 0 被提升(sheng)，达到了稳定输(shu)出电(dian)(dian)压(ya)的(de)目的(de)。
近年来已有(you)大量(liang)集成稳(wen)压(ya)(ya)器(qi)产品(pin)问世，品(pin)种很多(duo)(duo)，结构也各不相同。目前用得较多(duo)(duo)的有(you)三端集成稳(wen)压(ya)(ya)器(qi)，有(you)输(shu)出正电(dian)(dian)压(ya)(ya)的CW7800 系列和输(shu)出负电(dian)(dian)压(ya)(ya)的 CW7900 系列等产品(pin)。输(shu)出电(dian)(dian)流从 0.1A ～ 3A ，输(shu)出电(dian)(dian)压(ya)(ya)有(you) 5V、 6V 、 9V 、 12V 、 15V 、 18V 、 24V 等多(duo)(duo)种。
这种集成稳(wen)压(ya)器只有三个端子，稳(wen)压(ya)电路的所有部(bu)分包括大功率调(diao)整管以及(ji)保护电路等都已集成在(zai)芯(xin)片(pian)内。使用时只要加上散热片(pian)后(hou)接(jie)到整流滤(lv)波电路后(hou)面就(jiu)行了。外(wai)围元(yuan)件少，稳(wen)压(ya)精度(du)高，工作可靠，一(yi)般不需调(diao)试。
图 4 （ e ）是(shi)(shi)一个(ge)三端稳压器电路(lu)。图中 C 是(shi)(shi)主(zhu)滤波电容(rong)， C1 、 C2 是(shi)(shi)消(xiao)除寄生(sheng)振荡的电容(rong) ,VD 是(shi)(shi)为防(fang)止输入短路(lu)烧(shao)坏集(ji)成块而(er)使用的保护二极管。
电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)是(shi)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中(zhong)比较简单(dan)然而(er)却是(shi)应(ying)用(yong)最广(guang)的电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)。拿到一张电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)图时，应(ying)该： ① 先按“整流 — 滤波 — 稳(wen)压(ya)(ya)”的次序把整个(ge)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)分(fen)(fen)解(jie)开来，逐级细细分(fen)(fen)析(xi)。 ② 逐级分(fen)(fen)析(xi)时要分(fen)(fen)清(qing)主电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)和(he)(he)(he)辅助电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)、主要元(yuan)件(jian)和(he)(he)(he)次要元(yuan)件(jian)，弄(nong)清(qing)它(ta)们的作(zuo)用(yong)和(he)(he)(he)参数要求等(deng)。例(li)如开关稳(wen)压(ya)(ya)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)中(zhong)，电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)感电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容和(he)(he)(he)续流二极(ji)管(guan)(guan)就是(shi)它(ta)的关键元(yuan)件(jian)。 ③ 因为晶(jing)体(ti)管(guan)(guan)有 NPN 和(he)(he)(he) PNP 型两类，某(mou)些(xie)集成电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)要求双电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)供电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，所以一个(ge)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)往往包括有不同(tong)(tong)极(ji)性不同(tong)(tong)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)值(zhi)和(he)(he)(he)好几组(zu)输出(chu)(chu)。读图时必须分(fen)(fen)清(qing)各组(zu)输出(chu)(chu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)的数值(zhi)和(he)(he)(he)极(ji)性。在组(zu)装和(he)(he)(he)维(wei)修时也要仔(zi)细分(fen)(fen)清(qing)晶(jing)体(ti)管(guan)(guan)和(he)(he)(he)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)解(jie)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容的极(ji)性，防止(zhi)出(chu)(chu)错。 ④ 熟悉(xi)某(mou)些(xie)习惯画法(fa)和(he)(he)(he)简化(hua)画法(fa)。 ⑤ 最后把整个(ge)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)从前到后全面综合贯通(tong)起来。这张电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)图也就读懂(dong)了。
例 1 电热毯控温电路
图 5 是(shi)一个电(dian)热毯电(dian)路。开(kai)关在“ 1 ”的(de)位置是(shi)低(di)(di)温(wen)(wen)档(dang)。 220 伏市(shi)电(dian)经二极管后(hou)接到电(dian)热毯，因为(wei)是(shi)半波(bo)整流，电(dian)热毯两(liang)端所加的(de)是(shi)约 100 伏的(de)脉动直流电(dian)，发热不(bu)高，所以是(shi)保温(wen)(wen)或低(di)(di)温(wen)(wen)状(zhuang)态。开(kai)关扳到“ 2 ”的(de)位置， 220 伏市(shi)电(dian)直接接到电(dian)热毯上(shang)，所以是(shi)高温(wen)(wen)档(dang)。
例 2 高压电子灭蚊蝇器
图 6 是(shi)利(li)用(yong)倍(bei)压(ya)(ya)整流(liu)(liu)原理(li)得到(dao)小电(dian)(dian)(dian)流(liu)(liu)直(zhi)流(liu)(liu)高(gao)(gao)压(ya)(ya)电(dian)(dian)(dian)的灭蚊(wen)蝇(ying)(ying)器(qi)。 220伏交流(liu)(liu)经(jing)过四倍(bei)压(ya)(ya)整流(liu)(liu)后输出电(dian)(dian)(dian)压(ya)(ya)可达 1100 伏，把这个直(zhi)流(liu)(liu)高(gao)(gao)压(ya)(ya)加到(dao)平(ping)行的金属丝网(wang)上。网(wang)下放诱饵，当苍(cang)蝇(ying)(ying)停在网(wang)上时(shi)造成短(duan)路，电(dian)(dian)(dian)容(rong)器(qi)上的高(gao)(gao)压(ya)(ya)通过苍(cang)蝇(ying)(ying)身体放电(dian)(dian)(dian)把蝇(ying)(ying)击毙(bi)。苍(cang)蝇(ying)(ying)尸体落下后，电(dian)(dian)(dian)容(rong)器(qi)又被充电(dian)(dian)(dian)，电(dian)(dian)(dian)网(wang)又恢复高(gao)(gao)压(ya)(ya)。这个高(gao)(gao)压(ya)(ya)电(dian)(dian)(dian)网(wang)电(dian)(dian)(dian)流(liu)(liu)很小，因此对人无害。
由于昆虫(chong)夜间有趋光性，因(yin)此(ci)如(ru)在这(zhei)电网后面放一个 3 瓦荧光灯(deng)或小型黑光灯(deng)，就可以诱杀(sha)蚊虫(chong)和有害昆虫(chong)。
例 3 实用稳压电源
图 7 是(shi)(shi)一个(ge)(ge)实用(yong)(yong)的(de)稳(wen)压(ya)(ya)电(dian)(dian)源。输出(chu)电(dian)(dian)压(ya)(ya) 3 ～ 9 伏可(ke)(ke)调(diao)，输出(chu)电(dian)(dian)流最大 100 毫(hao)安。这个(ge)(ge)电(dian)(dian)路(lu)(lu)就是(shi)(shi)串联型稳(wen)压(ya)(ya)电(dian)(dian)源电(dian)(dian)路(lu)(lu)。要注意(yi)的(de)是(shi)(shi) :① 整流桥(qiao)的(de)画法(fa)和图 2 （ c ）不同，实际上(shang)它就是(shi)(shi)桥(qiao)式整流电(dian)(dian)路(lu)(lu)。 ② 这个(ge)(ge)电(dian)(dian)路(lu)(lu)使用(yong)(yong) PNP 型锗管(guan)，所以输出(chu)是(shi)(shi)负(fu)电(dian)(dian)压(ya)(ya)，正极(ji)接地。 ③ 用(yong)(yong)两(liang)个(ge)(ge)普通二(er)(er)极(ji)管(guan)代替稳(wen)压(ya)(ya)管(guan)。任何二(er)(er)极(ji)管(guan)的(de)正向压(ya)(ya)降都是(shi)(shi)基本(ben)不变(bian)的(de)，因此可(ke)(ke)用(yong)(yong)二(er)(er)极(ji)管(guan)代替稳(wen)压(ya)(ya)管(guan)。 2AP 型二(er)(er)极(ji)管(guan)的(de)正向压(ya)(ya)降约(yue)是(shi)(shi) 0.3 伏， 2CP 型约(yue)是(shi)(shi) 0.7 伏， 2CZ 型约(yue)是(shi)(shi) 1 伏。图中用(yong)(yong)了两(liang)个(ge)(ge) 2CZ 二(er)(er)极(ji)管(guan)作基准电(dian)(dian)压(ya)(ya)。 ④ 取样电(dian)(dian)阻是(shi)(shi)一个(ge)(ge)电(dian)(dian)位器，所以输出(chu)电(dian)(dian)压(ya)(ya)是(shi)(shi)可(ke)(ke)调(diao)的(de)。
直(zhi)流电(dian)源(yuan)很重要，电(dian)子产品不可少，
一般(ban)组成(cheng)五部(bu)分，变压、整流、滤波好(hao)，
稳压、保护在后(hou)面(mian)，输出直(zhi)流很可靠。
整流(liu)电路有两(liang)种(zhong)，单相(xiang)整流(liu)三(san)相(xiang)整，
单相整流小功率，电路形(xing)式分四种，
半波(bo)、全(quan)波(bo)与桥式(shi)，倍压整流靠电(dian)容。
半(ban)波(bo)整流一VD，正周(zhou)导通负周(zhou)止，
输(shu)出电(dian)压零四(si)五，VD反(fan)压根2值，
电路简单元件少(shao)，输出直流电压低。
全波VD轮流通，两个半波来合成(cheng)，
输(shu)出电压零点(dian)九，反压半波(bo)二(er)倍整，
压高(gao)、流(liu)大、效率高(gao)，变中抽(chou)头(tou)大功用。
桥(qiao)式整流4VD，连变次级(ji)极性异，
同(tong)负一(yi)端(duan)电(dian)源正，同(tong)正一(yi)端(duan)电(dian)负极，
输出电(dian)压零点九，VD反压根2值，
率高、压高、反压低，应(ying)用广泛受人喜。
高压小流直流源，倍(bei)压整流来实现，
N只(zhi)VD N只(zhi)C，VD整流C充电。
滤波(bo)电路去脉(mai)动，电容、电感(gan)及复用(yong)，
π型滤波分(fen)两种，感容组合与阻容。
电(dian)容(rong)滤波并电(dian)容(rong)，直(zhi)流开路交(jiao)流通，
电容充(chong)电又放(fang)电，输出直流波形平。
电(dian)感滤波串电(dian)感，直流导通交流断(duan)，
电(dian)感储(chu)能又(you)释能，输出平稳直流电(dian)。
Lc型滤波受人(ren)赞，并联电(dian)容(rong)串电(dian)感(gan)，
电容通交感(gan)通直，兼有两者的优点(dian)。
π型(xing)滤波效(xiao)果好，两种形式要知(zhi)道，
电感、阻容(rong)的组(zu)合(he)，不同场(chang)合(he)注意挑。
串联稳压4组(zu)成，基准、取(qu)样(yang)与调整，
还有比(bi)较放大(da)路，流大(da)调压广泛用。
开关电源体积小(xiao)，质量轻来效率高，
家用电器(qi)采用多，故(gu)障发生也(ye)不少，
分(fen)类方法有多种(zhong)，串联应用(yong)为主要，
VT周期开(kai)与关，开(kai)有电(dian)压(ya)关压(ya)冒，
改(gai)变脉(mai)冲(chong)占空比，实现稳压应(ying)知道。
分立元(yuan)件较复杂(za)，控制还(hai)是集成好，
专用(yong)集成品种(zhong)多(duo)，逐个了解就知晓。
联(lian)系(xi)方(fang)式(shi)：邹先生
联系(xi)电话：0755-83888366-8022
手机：18123972950
QQ：2880195519
联(lian)系(xi)地(di)址：深圳市(shi)福田区(qu)车公庙天(tian)安数码城天(tian)吉大(da)厦CD座(zuo)5C1
请搜微(wei)信公(gong)众号(hao)(hao):“KIA半导体”或扫(sao)一扫(sao)下图“关注”官(guan)方微(wei)信公(gong)众号(hao)(hao)
请“关注”官方微信公众号:提供 MOS管 技术帮(bang)助(zhu)
