电工电子电路(lu)图(tu)详(xiang)解-最(zui)常(chang)用电路(lu)图(tu)大全详(xiang)解(实物篇)KIA MOS管
信(xin)息来源:本站 日期:2018-05-04
电路(lu)识别是初中(zhong)物理电学的重点(dian)之一,电路识别虽然是有些难度,但还是有章可循的,电路识别相关的包括二部分:电路图简化以及电路图、实物图互化。这次我先介绍一个简化电路图的方法,我把它叫做标号法。这种方法简单易学、练练就会、便(bian)于(yu)记忆,而(er)且适用于(yu)所有电路,是(shi)居家旅(lv)行、特别是(shi)简化电路的(de)杀手(shou)锏。
1、 标号:电路每个节点编号,标号遵循以下原则
(1) 从正(zheng)极开始(shi)标1
(2) 导线连通的(de)节(jie)点标(biao)同(tong)样(yang)的(de)数字
(3) 沿着(zhe)导线过一个用电器,数字(zi)+1
(4) 到(dao)遇(yu)到(dao)电(dian)源(yuan)负(fu)极为止
(5) 要求所有(you)点的标号要大(da)于(yu)等于(yu)1,小于(yu)等于(yu)负极的标号
2、画图
(1) 在平面(mian)上画出节(jie)点号(hao)
(2) 根据原图(tu)画出节点之间的用电器或(huo)电表
(3) 整(zheng)理,美化
3、注意事项
(1) 当用电(dian)器两端标(biao)号(hao)不等时,电(dian)流(liu)从小标(biao)号(hao)点到大标(biao)号(hao)点,因为(wei)小标(biao)号(hao)更接近正(zheng)极
(2) 当用电器(qi)(qi)两端标号相(xiang)等时,相(xiang)当于一根导线接在用电器(qi)(qi)两端,因(yin)此用电器(qi)(qi)短路(lu)没(mei)有(you)电流
如图(tu),这道题太典型(xing)了(le),估(gu)计每(mei)个(ge)老(lao)师(shi)都要讲(jiang)。答案估(gu)计大家都知道,同学甲说(shuo)这个(ge)是串联;同学乙说(shuo),不(bu)对(dui)!R1应该被短(duan)路(lu)了(le),没看见上(shang)(shang)面的”天线”么;这时(shi)候老(lao)师(shi)蹦(beng)出来(lai),说(shuo)你们都错了(le),实际上(shang)(shang)是标(biao)准的并联电路(lu)。倒~,确实不(bu)好理解,很多同学老(lao)师(shi)讲(jiang)过一遍还是搞不(bu)清楚为啥(sha),最后(hou)背下结(jie)论了(le)事。现在轮到我们的标(biao)号(hao)大法上(shang)(shang)场(chang)了(le),为了(le)说(shuo)明方便,先(xian)用字母对(dui)每(mei)个(ge)点进行标(biao)记下
首(shou)先进行(xing)标(biao)(biao)号,我们(men)的(de)标(biao)(biao)号用红色(se)数字表示,从电源正极(ji)(ji)出来(lai)a点标(biao)(biao)1,同样(yang)在一(yi)条导线(xian)上(shang)的(de)b、d点也(ye)标(biao)(biao)1;检(jian)查所有该(gai)标(biao)(biao)1的(de)都标(biao)(biao)了,那(nei)就(jiu)过一(yi)个电阻吧!例如从b点过到(dao)(dao)c点,这样(yang)c点标(biao)(biao)2。同一(yi)导线(xian)上(shang)的(de)e、f、g点都标(biao)(biao)2,这样(yang)我们(men)惊(jing)奇的(de)发现已经到(dao)(dao)电源负极(ji)(ji)了!标(biao)(biao)号结束!轻松(song)~
进入(ru)第(di)二步画图(tu)阶段,先(xian)画出节点(dian)号1,2,其中1节点(dian)电(dian)源正(zheng)极,2节点(dian)接电(dian)源负极,如下图(tu);
然后(hou)再原(yuan)图(tu)中查找每个(ge)电(dian)阻(zu)两端(duan)的节点(dian)(dian)标号,放到简化图(tu)中对应标号之(zhi)间(jian),我们看到R1、R2、R3都在1、2点(dian)(dian)之(zhi)间(jian),所以把(ba)它们仨依次连接在1、2点(dian)(dian)之(zhi)间(jian),就(jiu)形成了右图(tu),很~清(qing)纯的并联电(dian)路(lu),不是么(me)?
例2:简(jian)化3个(ge)电路图。(1) 电源(yuan)正(zheng)极接(jie)A,负极接(jie)C,只(zhi)闭合(he)S2;(2) 只(zhi)闭合(he)S3;(3) 电源(yuan)正(zheng)极接(jie)A,负极接(jie)B,只(zhi)断开S2
第(di)1问
a. 标(biao)号(hao),A点(dian)出来a、b、c、d都标(biao)1,S1断开,所(suo)以(yi)(yi)e、f点(dian)不能(neng)(neng)标(biao)1;过(guo)R1后(hou)(hou),e、f、h标(biao)2,S2闭(bi)合,所(suo)以(yi)(yi)l也标(biao)2;过(guo)R2,i,j,k都标(biao)3。有同学问,能(neng)(neng)否由i过(guo)R3,在(zai)g点(dian)标(biao)4?这是不可以(yi)(yi)的,参(can)看口(kou)诀第五条,g点(dian)的标(biao)号(hao)不能(neng)(neng)比i大(da),而且g点(dian)后(hou)(hou)面(mian)S3断开,使得电(dian)(dian)流(liu)无处流(liu)了,所(suo)以(yi)(yi)正确答案是这个电(dian)(dian)路图R3并没(mei)有被接入电(dian)(dian)路。标(biao)号(hao)结果参(can)看上图
b. 画图(tu),先画三个节点(dian);
找每(mei)个用电器所在(zai)的(de)位置,R1和(he)V1在(zai)1,2之间(jian)(jian),R2和(he)V2在(zai)2,3之间(jian)(jian),装上即可;R3的(de)g点没有标号,所以(yi)没有接入电路
第2问
a.标(biao)号,标(biao)1节(jie)点(dian)与(yu)原(yuan)来相(xiang)同;由于S3闭合,g点(dian)闭合,由于S2断开,l点(dian)无(wu)法标(biao)注;3节(jie)点(dian)标(biao)注与(yu)原(yuan)来相(xiang)同
b.画图(tu):可以看到R2不在(zai)图(tu)里(li)
第3问
a.标(biao)号(hao),A点(dian)正极(ji),S1,S3闭合,所(suo)以a,b,c,d,e,f,g,h都(dou)标(biao)记(ji)1,过R3标(biao)记(ji)i,j,k标(biao)记(ji)2;过R2,l标(biao)记(ji)3,B点(dian)是负极(ji),停止标(biao)号(hao)
b.画图,R1,V1两(liang)端都是(shi)1,说明也(ye)就是(shi)他(ta)们被(bei)短路(lu)了,没有接(jie)入电(dian)路(lu);R3,V2接(jie)在1,2之间;R2接(jie)在2,3之间
如果遇到电流表(biao),可将电流表(biao)视为导线,然后在(zai)简化图(tu)中放入电流表(biao)。
用电路元件(jian)符号表示电路连接的(de)图,叫(jiao)电路图。电路图是人们为(wei)研究、工程规划的(de)需要,用物理电学(xue)标(biao)准化的(de)符号绘制的(de)一种表示各(ge)元器件(jian)组成及器件(jian)关(guan)系的(de)原(yuan)理布(bu)局图,可以(yi)得知组件(jian)间的(de)工作(zuo)原(yuan)理,为(wei)分(fen)析性能、安(an)装电子、电器产品提供规划方案。
电(dian)(dian)路(lu)图是电(dian)(dian)子工程师必学的基本技(ji)能之一(yi),本文集(ji)合了稳压电(dian)(dian)源、DCDC转换电(dian)(dian)源、开关(guan)电(dian)(dian)源、充(chong)电(dian)(dian)电(dian)(dian)路(lu)、恒流源相关(guan)的经典电(dian)(dian)路(lu)资(zi)料,为工程师提供最新鲜(xian)的电(dian)(dian)路(lu)图参考资(zi)料
此稳(wen)压电源(yuan)可调范围在3.5V~25V之(zhi)间任意(yi)(yi)调节,输(shu)出(chu)电流(liu)大,并(bing)采用可调稳(wen)压管式电路,从(cong)而得到满意(yi)(yi)平稳(wen)的(de)输(shu)出(chu)电压。
工作(zuo)原理:经整(zheng)流滤波(bo)后直流电(dian)(dian)压(ya)(ya)由R1提(ti)供给调(diao)整(zheng)管(guan)的基极(ji),使调(diao)整(zheng)管(guan)导(dao)通(tong)(tong),在V1导(dao)通(tong)(tong)时电(dian)(dian)压(ya)(ya)经过(guo)RP、R2使V2导(dao)通(tong)(tong),接着V3也导(dao)通(tong)(tong),这时V1、V2、 V3的发射极(ji)和集(ji)电(dian)(dian)极(ji)电(dian)(dian)压(ya)(ya)不再变化(其作(zuo)用完(wan)全与稳(wen)压(ya)(ya)管(guan)一(yi)样)。调(diao)节RP,可得到平稳(wen)的输(shu)出(chu)电(dian)(dian)压(ya)(ya),R1、RP、R2与R3比值(zhi)(zhi)决定本电(dian)(dian)路输(shu)出(chu)的电(dian)(dian)压(ya)(ya)值(zhi)(zhi)。
元(yuan)器(qi)件选(xuan)(xuan)(xuan)(xuan)择:变压器(qi)T选(xuan)(xuan)(xuan)(xuan)用(yong)(yong)80W~100W,输(shu)(shu)入AC220V,输(shu)(shu)出双绕(rao)组AC28V。FU1选(xuan)(xuan)(xuan)(xuan)用(yong)(yong)1A,FU2选(xuan)(xuan)(xuan)(xuan)用(yong)(yong)3A~5A。VD1、VD2选(xuan)(xuan)(xuan)(xuan)用(yong)(yong) 6A02。RP选(xuan)(xuan)(xuan)(xuan)用(yong)(yong)1W左右普通电(dian)(dian)位器(qi),阻值为250K~330K,C1选(xuan)(xuan)(xuan)(xuan)用(yong)(yong)3300μF/35V电(dian)(dian)解(jie)电(dian)(dian)容(rong),C2、C3选(xuan)(xuan)(xuan)(xuan)用(yong)(yong)0.1μF独石电(dian)(dian)容(rong),C4选(xuan)(xuan)(xuan)(xuan)用(yong)(yong) 470μF/35V电(dian)(dian)解(jie)电(dian)(dian)容(rong)。R1选(xuan)(xuan)(xuan)(xuan)用(yong)(yong)180~220Ω/0.1W~1W,R2、R4、R5选(xuan)(xuan)(xuan)(xuan)用(yong)(yong)10KΩ、1/8W。V1选(xuan)(xuan)(xuan)(xuan)用(yong)(yong)2N3055,V2选(xuan)(xuan)(xuan)(xuan)用(yong)(yong) 3DG180或(huo)2SC3953,V3选(xuan)(xuan)(xuan)(xuan)用(yong)(yong)3CG12或(huo)3CG80。
无(wu)论检修(xiu)电(dian)(dian)脑还(hai)是(shi)电(dian)(dian)子(zi)制作都(dou)离不开稳压(ya)电(dian)(dian)源(yuan),下(xia)面介绍一款直流电(dian)(dian)压(ya)从3V到15V连续可调的(de)稳压(ya)电(dian)(dian)源(yuan),最(zui)大电(dian)(dian)流可达10A,该电(dian)(dian)路用了具(ju)有温度补偿特性(xing)的(de),高精度的(de)标准电(dian)(dian)压(ya)源(yuan)集成(cheng)电(dian)(dian)路TL431,使(shi)(shi)稳压(ya)精度更高,如果没(mei)有特殊要求(qiu),基本能满足正常(chang)维(wei)修(xiu)使(shi)(shi)用,电(dian)(dian)路见下(xia)图(tu)。
其工作原理(li)分两部分,第一(yi)部分是一(yi)路(lu)(lu)固(gu)定的5V1.5A稳压电(dian)(dian)源(yuan)电(dian)(dian)路(lu)(lu),第二部分是另一(yi)路(lu)(lu)由(you)3至(zhi)15V连续(xu)可调(diao)的高精度大电(dian)(dian)流稳压电(dian)(dian)路(lu)(lu)。
第一路的电路非常简单,由变压器次级8V交流电压通过硅桥QL1整流后的直流电压经C1电解电容滤波后,再由5V三端稳压块LM7805不用作任何调整就可在输出端产生固定的5V1A稳压电源,这个电源在检修电脑板时完全可以当作内部电源使用。
第二部分与普通串联型稳压电源基本相同,所不同的是使用了具有温度补偿特性的,高精度的标准电压源集成电路TL431,所以使电路简化,成本降低,而稳压性能却很高。
图中电(dian)阻R4,稳(wen)压(ya)(ya)管(guan)TL431,电(dian)位器R3组成(cheng)一个连续可调(diao)得恒压(ya)(ya)源(yuan),为BG2基(ji)极(ji)提供基(ji)准电(dian)压(ya)(ya),稳(wen)压(ya)(ya)管(guan)TL431的稳(wen)压(ya)(ya)值连续可调(diao),这个稳(wen)压(ya)(ya)值决定了稳(wen)压(ya)(ya)电(dian)源(yuan)的最大输出(chu)电(dian)压(ya)(ya),如果(guo)你(ni)想把可调(diao)电(dian)压(ya)(ya)范围扩大,可以改变R4 和R3的电(dian)阻值,当然变压(ya)(ya)器的次级(ji)电(dian)压(ya)(ya)也要提高。
变(bian)压(ya)器的(de)功(gong)率可(ke)根据输(shu)出(chu)电流灵活掌(zhang)握,次级电压(ya)15V左右(you)。桥(qiao)式整流用(yong)的(de)整流管QL用(yong)15-20A硅桥(qiao),结构紧凑,中(zhong)间有固(gu)定(ding)螺丝,可(ke)以直接固(gu)定(ding)在机壳的(de)铝板上,有利散(san)热。
调整管(guan)用的(de)(de)(de)(de)是大(da)电流(liu)NPN型金属壳硅管(guan),由于它的(de)(de)(de)(de)发(fa)热(re)量(liang)很(hen)大(da),如(ru)果机箱允(yun)许(xu),尽量(liang)购(gou)买(mai)大(da)的(de)(de)(de)(de)散热(re)片(pian),扩大(da)散热(re)面积(ji),如(ru)果不(bu)需要大(da)电流(liu),也可以换用功率小一点的(de)(de)(de)(de)硅管(guan),这样可以做的(de)(de)(de)(de)体积(ji)小一些(xie)。
滤波(bo)用50V4700uF电(dian)解电(dian)容(rong)(rong)C5和C7分别用三只并联(lian),使大电(dian)流输出(chu)更稳(wen)定,另外这个电(dian)容(rong)(rong)要买体积相(xiang)对(dui)大一点的,那些体积较小的同(tong)样标注50V4700uF尽量不(bu)用,当遇到(dao)电(dian)压波(bo)动频繁,或长时(shi)间不(bu)用,容(rong)(rong)易(yi)失效。
最后再说一(yi)下电(dian)源(yuan)变压器(qi),如(ru)果(guo)没(mei)有能(neng)力自己绕制,有买(mai)(mai)不(bu)(bu)到现成(cheng)(cheng)的(de),可(ke)以买(mai)(mai)一(yi)块现成(cheng)(cheng)的(de)200W以上的(de)开关电(dian)源(yuan)代(dai)替变压器(qi),这样(yang)稳压性能(neng)还可(ke)进一(yi)步提高,制作(zuo)成(cheng)(cheng)本却差不(bu)(bu)太多,其它电(dian)子(zi)元件无特(te)殊要求,安装完成(cheng)(cheng)后不(bu)(bu)用太大调(diao)整就可(ke)正常工作(zuo)。
下图为(wei)UC3842 内部框图和(he)引脚图,UC3842 采用固定(ding)工作频率(lv)脉(mai)冲(chong)宽度可控(kong)调(diao)制方式,共有(you)8 个引脚,各脚功能如下:
①脚是(shi)误差放(fang)大(da)器的输出端,外接阻容(rong)元(yuan)件用(yong)于改善误差放(fang)大(da)器的增(zeng)益和频率(lv)特性;
②脚是(shi)反馈电(dian)(dian)压(ya)输入端,此(ci)脚电(dian)(dian)压(ya)与误(wu)差(cha)放大器同(tong)相端的2.5V 基准(zhun)电(dian)(dian)压(ya)进行(xing)比(bi)较,产生误(wu)差(cha)电(dian)(dian)压(ya),从而控制(zhi)脉冲宽度(du);
③脚(jiao)为电流检测(ce)输入端, 当(dang)检测(ce)电压超过(guo)1V时缩小脉冲(chong)宽度使电源处于间歇(xie)工(gong)作(zuo)状态;
④脚为(wei)定时端,内(nei)部振荡器(qi)的(de)工作频率由(you)外接的(de)阻容(rong)时间常数决定,f=1.8/(RT×CT);
⑤脚(jiao)为公共(gong)地端(duan);
⑥脚(jiao)为推挽输出端,内部为图腾柱式(shi),上升(sheng)、下降时间仅为50ns 驱动能力为±1A ;
⑦脚(jiao)是直流电(dian)(dian)源供电(dian)(dian)端,具有欠、过压锁定功能,芯片功耗为15mW;⑧脚(jiao)为5V 基准电(dian)(dian)压输出端,有50mA 的负载(zai)能力。
UC3842是一(yi)种(zhong)性能优异(yi)、应用广泛(fan)、结构较简(jian)单的(de)PWM开关电源集成(cheng)控制器,由于它只(zhi)有一(yi)个输出(chu)端,所以(yi)主要(yao)用于音端控制的(de)开关电源。
UC3842 7脚为(wei)电(dian)(dian)压(ya)(ya)输入(ru)端,其启(qi)动电(dian)(dian)压(ya)(ya)范围(wei)为(wei)16-34V。在电(dian)(dian)源启(qi)动时(shi),VCC﹤16V,输入(ru)电(dian)(dian)压(ya)(ya)施密(mi)物比(bi)较器(qi)输出(chu)为(wei)0,此时(shi)无基准电(dian)(dian)压(ya)(ya)产生(sheng),电(dian)(dian)路(lu)(lu)不工作;当 Vcc﹥16V时(shi)输入(ru)电(dian)(dian)压(ya)(ya)施密(mi)特比(bi)较器(qi)送(song)出(chu)高电(dian)(dian)平到5V蕨稳(wen)压(ya)(ya)器(qi),产生(sheng)5V基准电(dian)(dian)压(ya)(ya),此电(dian)(dian)压(ya)(ya)一(yi)方面供(gong)销内部电(dian)(dian)路(lu)(lu)工作另(ling)一(yi)方面通(tong)过
⑧脚向外部提供参(can)考电(dian)压。一旦施(shi)(shi)密特比较器(qi)翻转为(wei)高电(dian)平(芯片(pian)开始工(gong)作(zuo)以后),Vcc可以在10V-34V范围内变化而(er)不影响电(dian)路的(de)工(gong)作(zuo)状(zhuang)态(tai)。当Vcc低(di)于10V时,施(shi)(shi)密特比较器(qi)又翻转为(wei)低(di)电(dian)平,电(dian)路停(ting)止工(gong)作(zuo)。
当基准稳(wen)压(ya)源有(you)5V基准电压(ya)输(shu)出(chu)时,基准电压(ya)检(jian)测逻辑(ji)比(bi)较器即达出(chu)高(gao)电平(ping)信号(hao)到(dao)输(shu)出(chu)电路。同时,振(zhen)荡器将根据(ju)④脚外接Rt、Ct参数(shu)产生 f=/Rt.Ct的振(zhen)荡信号(hao),此信号(hao)一路直接加到(dao)图(tu)腾柱电路的输(shu)入端
另一(yi)路加到PWM脉宽(kuan)市制(zhi)RS触发(fa)器的(de)置位端(duan)(duan),RS型(xing)PWN脉宽(kuan)调制(zhi)器的(de)R端(duan)(duan)接电(dian)流(liu)检测(ce)比较器输出(chu)端(duan)(duan)。R端(duan)(duan)为(wei)占空(kong)调节控(kong)制(zhi)端(duan)(duan),当(dang)R电(dian)压上(shang)升时(shi),Q端(duan)(duan)脉冲加宽(kuan),同时(shi)⑥脚送(song)出(chu)脉宽(kuan)也加宽(kuan)(占空(kong)比增多);当(dang)R端(duan)(duan)电(dian)压下(xia)降(jiang)时(shi),Q端(duan)(duan)脉冲变窄,同时(shi) ⑥脚送(song)出(chu)脉宽(kuan)也变变窄(占空(kong)比减小)。
UC3842各点(dian)(dian)(dian)时(shi)序如图所(suo)示,只有(you)当E点(dian)(dian)(dian)为高电(dian)(dian)(dian)(dian)平(ping)时(shi)才(cai)有(you)信号输(shu)出 ,并且a、b点(dian)(dian)(dian)全为高电(dian)(dian)(dian)(dian)平(ping)时(shi),d点(dian)(dian)(dian)才(cai)送(song)出高电(dian)(dian)(dian)(dian)平(ping),c点(dian)(dian)(dian)送(song)出低电(dian)(dian)(dian)(dian)平(ping),否则(ze)d点(dian)(dian)(dian)送(song)出低电(dian)(dian)(dian)(dian)平(ping),c点(dian)(dian)(dian)送(song)出高电(dian)(dian)(dian)(dian)平(ping)。②脚(jiao)一般接输(shu)出电(dian)(dian)(dian)(dian)压取样(yang)信号,也称反(fan)馈(kui)信号。当② 脚(jiao)电(dian)(dian)(dian)(dian)压上(shang)升(sheng)时(shi),①脚(jiao)电(dian)(dian)(dian)(dian)压将下降,R端(duan)电(dian)(dian)(dian)(dian)压亦随之下降,于是⑥脚(jiao)脉冲(chong)变窄;反(fan)之,⑥脚(jiao)脉冲(chong)变宽。
③脚(jiao)为电(dian)(dian)流传(chuan)感端,通(tong)常在功率管(guan)的(de)(de)(de)源极或发射极串入(ru)一小(xiao)阻(zu)值取(qu)样电(dian)(dian)阻(zu),将(jiang)流过开关管(guan)的(de)(de)(de)电(dian)(dian)流转为电(dian)(dian)压(ya),并将(jiang)此电(dian)(dian)压(ya)引入(ru)境脚(jiao)。当负(fu)载(zai)短路或其它原因(yin)引起(qi)功率管(guan)电(dian)(dian)流增加,并使取(qu)样电(dian)(dian)阻(zu)上的(de)(de)(de)电(dian)(dian)压(ya)超过1V时,⑥脚(jiao)就停(ting)止脉(mai)冲输出,这样就可以有(you)效的(de)(de)(de)保护(hu)功率管(guan)不受损坏(huai)。
由(you)TOP224P构成的 12V、20W开关(guan)直(zhi)流(liu)稳压电源电路如图所示。
电路(lu)中(zhong)使用(yong)两片集成电路(lu):TOP224P型(xing)(xing)三端单片开(kai)关电源(yuan)(yuan)(IC1),PC817A型(xing)(xing)线性光耦合器(qi) (IC2)。交流电源(yuan)(yuan)经过UR和Cl整流滤波后(hou)产生(sheng)直流高压Ui,给高频变(bian)压器(qi)T的一(yi)次绕组供电。
VDz1和VD1能(neng)将漏感产(chan)生的(de)尖(jian)峰电(dian)(dian)压钳位到(dao)安(an)全值, 并(bing)能(neng)衰减振铃电(dian)(dian)压。VDz1采用反向击穿电(dian)(dian)压为200V的(de)P6KE200型瞬态电(dian)(dian)压抑(yi)制器,VDl选用1A/600V的(de)UF4005型超快恢复二极管。
二 次绕组电压(ya)(ya)通过(guo)V砬、C2、Ll和C3整流滤波,获(huo)得12V输出电压(ya)(ya)Uo。Uo值是由(you)VDz2稳定电压(ya)(ya)Uz2、光耦中LED的正(zheng)向压(ya)(ya)降UF、R1上(shang)的压(ya)(ya)降 这三者(zhe)之和来(lai)设定的。
改变(bian)高频变(bian)压(ya)器的(de)(de)匝数比和VDz2的(de)(de)稳压(ya)值,还可获得(de)其他(ta)输出电(dian)压(ya)值。R2和VDz2五还为12V输出提(ti)供(gong)一个假负载(zai),用以提(ti)高轻载(zai) 时(shi)的(de)(de)负载(zai)调(diao)整率。反馈(kui)绕组电(dian)压(ya)经VD3和C4整流滤波(bo)后(hou),供(gong)给(ji)TOP224P所需(xu)偏压(ya)。由(you)R2和VDz2来调(diao)节控制(zhi)端电(dian)流,通(tong)过(guo)改变(bian)输出占(zhan)空(kong)比达到稳压(ya)目 的(de)(de)。
共(gong)(gong)模扼流圈(quan)L2能减小(xiao)由一(yi)次绕(rao)(rao)组接D端的(de)(de)高压开关波(bo)形所(suo)产(chan)生的(de)(de)共(gong)(gong)模泄漏电流。C7为保护电容,用于滤掉由一(yi)次、二(er)次绕(rao)(rao)组耦合电容引起(qi)的(de)(de)干扰。C6可减 小(xiao)由一(yi)次绕(rao)(rao)组电流的(de)(de)基(ji)波(bo)与(yu)谐(xie)波(bo)所(suo)产(chan)生的(de)(de)差模泄漏电流。C5不仅能滤除加在控制端上的(de)(de)尖峰(feng)电流,而且决定自启动频率,它还与(yu)R1、R3一(yi)起(qi)对(dui)控制回路进行补(bu)偿(chang)。
本电源主要技术指标如下:
交(jiao)流输人(ren)电压范(fan)围:u=85~265V;
输入电(dian)网频率(lv):fLl=47~440Hz;
输(shu)出电压(Io=1.67A):Uo=12V;
最大(da)输出电流:IOM=1.67A;
连续输出功(gong)率:Po=20W(TA=25℃,或15W(TA=50℃);
电压(ya)调整(zheng)率:η=78%;
输出纹波电压的最大值:±60mV;
工作温(wen)度范围:TA=0~50℃。
由电(dian)(dian)(dian)(dian)(dian)池供电(dian)(dian)(dian)(dian)(dian)的(de)便携式电(dian)(dian)(dian)(dian)(dian)子产(chan)品一般都(dou)采(cai)用(yong)低(di)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)电(dian)(dian)(dian)(dian)(dian)压(ya),这样可(ke)减(jian)少(shao)电(dian)(dian)(dian)(dian)(dian)池数量,达到减(jian)小(xiao)产(chan)品尺寸及重量的(de)目的(de),故一般常(chang)用(yong)3~5V作为工作电(dian)(dian)(dian)(dian)(dian)压(ya),为保(bao)证(zheng)电(dian)(dian)(dian)(dian)(dian)路工作的(de)稳定(ding)性(xing)及精度(du),要求采(cai)用(yong)稳压(ya)电(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)供电(dian)(dian)(dian)(dian)(dian)。
若电(dian)路(lu)采用5V工(gong)作电(dian)压(ya),但另需一个较高的(de)工(gong)作电(dian)压(ya),这往(wang)往(wang)使设(she)计者为(wei)难(nan)。本文(wen)介绍一种采用两(liang)块升压(ya)模块组成的(de)电(dian)路(lu)可(ke)解(jie)决这一难(nan)题,并且只要两(liang)节电(dian)池(chi)供(gong)电(dian)。
该电(dian)路的(de)特点是外围元件少、尺寸小(xiao)、重量轻、输出(chu)+5V、+12V都是稳定的(de),满足便携式电(dian)子产(chan)品的(de)要求。+5V电(dian)源可输出(chu)60mA,+12V电(dian)源最(zui)大输出(chu)电(dian)流(liu)为5mA。
该电(dian)(dian)路(lu)如上图所示。它由AH805升(sheng)(sheng)压模块(kuai)及FP106升(sheng)(sheng)压模块(kuai)组成。AH805是一种(zhong)输入1.2~3V,输出(chu)(chu)5V的升(sheng)(sheng)压模块(kuai),在(zai)3V供电(dian)(dian)时可(ke)输出(chu)(chu) 100mA电(dian)(dian)流(liu)。FP106是贴(tie)片式(shi)升(sheng)(sheng)压模块(kuai),输入4~6V,输出(chu)(chu)固定(ding)电(dian)(dian)压为29±1V,输出(chu)(chu)电(dian)(dian)流(liu)可(ke)达(da)40mA,AH805及FP106都是一个电(dian)(dian)平控(kong)制(zhi)的关闭(bi)电(dian)(dian)源控(kong)制(zhi)端。
两节(jie)1.5V碱性电(dian)(dian)池输出的3V电(dian)(dian)压(ya)(ya)输入(ru)AH805,AH805输出+5V电(dian)(dian)压(ya)(ya),其一(yi)路(lu)作(zuo)5V输出,另一(yi)路(lu)输入(ru)FP106使其产生28~30V电(dian)(dian)压(ya)(ya),经(jing)稳(wen)压(ya)(ya)管稳(wen)压(ya)(ya)后输出+12V电(dian)(dian)压(ya)(ya)。
从图中可(ke)以看出,只要改(gai)变稳压管(guan)的(de)稳压值,即可(ke)获(huo)得不同的(de)输(shu)出电(dian)(dian)压,使用十(shi)分灵活(huo)。FP106的(de)第(di)⑤脚为控制(zhi)(zhi)(zhi)电(dian)(dian)源(yuan)(yuan)关(guan)闭端,在关(guan)闭电(dian)(dian)源(yuan)(yuan)时(shi),耗(hao)电(dian)(dian)几乎为零,当第(di)⑤脚加高电(dian)(dian)平》2.5V时(shi),电(dian)(dian)源(yuan)(yuan)导(dao)通;当第(di)⑤脚加低电(dian)(dian)平<0.4V时(shi),电(dian)(dian)源(yuan)(yuan)被关(guan)闭。可(ke)以用电(dian)(dian)路来控制(zhi)(zhi)(zhi)或(huo)手(shou)动(dong)控制(zhi)(zhi)(zhi),若(ruo)不需控制(zhi)(zhi)(zhi)时(shi),第(di)⑤脚与(yu)第(di) ⑧脚连接。
工作状态:
无负载:输入(ru):3.65V、18uA(相当600mAH的电池待机三年多)
有负载:输出:9.88V、50.2mA,输入(ru):3.65V、186.7mA,效(xiao)率为(wei)72%
工作原理:
无负载时,IC的 6脚(jiao)没有(you)电(dian),停止工作,输(shu)入端3.65V工作电(dian)流(liu)只(zhi)有(you)18uA(相当600mAH的电(dian)池待机三年多(duo))!
当有负载时(Q1有Ieb电(dian)(dian)流)8550的EC极导通,IC得(de)电(dian)(dian)工作。IC是(shi)否(fou)工作是(shi)由是(shi)否(fou)有负载决定(ding)的,就相(xiang)当一个电(dian)(dian)池。用IC做电(dian)(dian)压转换效率高,输出稳(wen)定(ding)!
这个(ge)电路(lu)加点改进,增(zeng)加功率可以做“不需开关的(de)4.2V转5V移动电源”。可以用个(ge)电池盒做手(shou)机的(de)后备电源!
碱性电池(chi)能(neng)否充(chong)(chong)电的(de)问(wen)题(ti),有两(liang)种不同的(de)说(shuo)法。有的(de)说(shuo)可(ke)(ke)以充(chong)(chong),效果非常好。有的(de)说(shuo)绝对不能(neng)充(chong)(chong),电池(chi)说(shuo)明提示了会有爆炸的(de)危(wei)险。事实(shi)上,碱性电池(chi)确可(ke)(ke)充(chong)(chong)电,充(chong)(chong)电次(ci)数一般为30-50次(ci)左(zuo)右。
实际上是由于在充(chong)(chong)电(dian)(dian)(dian)方法上的(de)掌握,导致了(le)截然(ran)不(bu)同(tong)的(de)两种后果。首(shou)先 ,碱性电(dian)(dian)(dian)池(chi)可(ke)以充(chong)(chong)电(dian)(dian)(dian)是毋庸(yong)置疑的(de),同(tong)时,在电(dian)(dian)(dian)池(chi)的(de)说明中,都提到碱性电(dian)(dian)(dian)池(chi)不(bu)可(ke)充(chong)(chong)电(dian)(dian)(dian),充(chong)(chong)电(dian)(dian)(dian)可(ke)能导致爆炸(zha)。
这(zhei)也是(shi)没错的,但(dan)是(shi)注意这(zhei)里的用词是(shi)“可(ke)能”导致(zhi)爆(bao)炸(zha)。你也可(ke)以(yi)理解(jie)为厂家的一种免责性的自我保护(hu)声明。碱性电(dian)池充(chong)电(dian)的关键是(shi)温(wen)(wen)度。只要(yao)能做到对电(dian)池充(chong)电(dian)时不出现高(gao)温(wen)(wen),就可(ke)以(yi)顺利地(di)完成充(chong)电(dian)过程,正确(que)的充(chong)电(dian)方法(fa)要(yao)求(qiu)有(you)几点:
小电流50MA
不(bu)过(guo)充1.7V,不(bu)过(guo)放1.3V
一些人尝试(shi)充(chong)(chong)(chong)电(dian)(dian)实践后,斩钉截铁地说(shuo)不能(neng)充(chong)(chong)(chong)电(dian)(dian),之(zhi)所(suo)以出现充(chong)(chong)(chong)不进电(dian)(dian)、用电(dian)(dian)时间(jian)短、漏(lou)液、爆炸(zha)等(deng)问(wen)题(ti),多数是充(chong)(chong)(chong)电(dian)(dian)器的问(wen)题(ti),如果充(chong)(chong)(chong)电(dian)(dian)器充(chong)(chong)(chong)电(dian)(dian)电(dian)(dian)流太大,远超过 50ma,如一些快(kuai)速充(chong)(chong)(chong)电(dian)(dian)器充(chong)(chong)(chong)电(dian)(dian)电(dian)(dian)流在200ma以上,直(zhi)接的后果是电(dian)(dian)池温度(du)很高(gao),摸上去烫手(shou),轻(qing)则会漏(lou)液,严重(zhong)的就会爆炸(zha)。
有(you)的(de)(de)(de)人使用镍氢(qing)充(chong)(chong)电(dian)(dian)电(dian)(dian)池(chi)充(chong)(chong)电(dian)(dian)器来(lai)充(chong)(chong),低档的(de)(de)(de)充(chong)(chong)电(dian)(dian)器没有(you)自动停充(chong)(chong)功能(neng),长时(shi)间的(de)(de)(de)充(chong)(chong)电(dian)(dian)导致电(dian)(dian)池(chi)过充(chong)(chong)也会(hui)出现漏(lou)液和爆炸(zha)。好一点的(de)(de)(de)充(chong)(chong)电(dian)(dian)器有(you)自动停充(chong)(chong)功能(neng),但(dan)停充(chong)(chong)电(dian)(dian)压(ya)一般设(she)定为镍氢(qing)充(chong)(chong)电(dian)(dian)电(dian)(dian)池(chi)的(de)(de)(de)1.42V,而碱性电(dian)(dian)池(chi)充(chong)(chong)满电(dian)(dian)压(ya)约(yue)为1.7V。
因此,电(dian)(dian)压太(tai)低,感觉上就是(shi)充(chong)不(bu)进电(dian)(dian),用电(dian)(dian)时间短,没(mei)什(shen)么(me)效(xiao)果。再有就是(shi)电(dian)(dian)池不(bu)过放指的是(shi)不(bu)要等到电(dian)(dian)池完全没(mei)电(dian)(dian)再充(chong)电(dian)(dian),这样操作,再好的电(dian)(dian)池也就能充(chong)三、五次,且效(xiao)果差(cha)。
一般(ban)建议用南孚碱性(xing)电(dian)(dian)(dian)(dian)池(chi)电(dian)(dian)(dian)(dian)压不低于(yu)1.3V。所以,你如果打算对碱性(xing)电(dian)(dian)(dian)(dian)池(chi)充电(dian)(dian)(dian)(dian),必须要(yao)有一个合格(ge)的充电(dian)(dian)(dian)(dian)器,充电(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)流50ma左(zuo)右(you),充电(dian)(dian)(dian)(dian)截止电(dian)(dian)(dian)(dian)压1.7V左(zuo)右(you)。看看你家(jia)的充电(dian)(dian)(dian)(dian)器吧。
市面上有(you)卖碱性电(dian)(dian)(dian)池专(zhuan)用(yong)充(chong)电(dian)(dian)(dian)器的,所(suo)谓(wei)专(zhuan)利(li)产品。实际上就是充(chong)电(dian)(dian)(dian)电(dian)(dian)(dian)压1.7V电(dian)(dian)(dian)流50ma的简(jian)单电(dian)(dian)(dian)路(lu)。利(li)用(yong)手边(bian)现有(you)的零(ling)件LM358和TL431,我做了(le)个简(jian)单电(dian)(dian)(dian)路(lu),截止电(dian)(dian)(dian)压1.67V自动(dong)停(ting)充(chong),成本两元而已。供感兴(xing)趣的朋友参考(kao)。
相关说明:
碱(jian)(jian)锰(meng)充电(dian)(dian)电(dian)(dian)池:是在碱(jian)(jian)性锌(xin)锰(meng)电(dian)(dian)池的(de)基础上发展起来的(de),由于应(ying)用了无汞化的(de)锌(xin)粉及(ji)新型(xing)添加剂,故又称为无汞碱(jian)(jian)锰(meng)电(dian)(dian)池。这种电(dian)(dian)池在不改变原碱(jian)(jian)性电(dian)(dian)池放电(dian)(dian)特性的(de)同时,又能充电(dian)(dian)使用几(ji)(ji)十次(ci)到几(ji)(ji)百(bai)次(ci),比较经济实惠(hui)。
碱(jian)性锌锰(meng)电(dian)(dian)池简称碱(jian)锰(meng)电(dian)(dian)池,它(ta)是在1882年(nian)(nian)(nian)研(yan)制成功(gong),1912年(nian)(nian)(nian)就已开发(fa),到了1949年(nian)(nian)(nian)才投产问世。人们发(fa)现,当用KOH电(dian)(dian)解质溶液代替NH4Cl做电(dian)(dian)解质时,无论是电(dian)(dian)解质还是结(jie)构(gou)上都(dou)有较大变化,电(dian)(dian)池的比能量和(he)放电(dian)(dian)电(dian)(dian)流都(dou)能得到显(xian)著的提高(gao)。
它的特点:
开路电压为(wei)1.5V;
工作温度范围宽在(zai)-20℃~60℃之间(jian),适于高寒地区使用;
大电流连续放电其(qi)容量是酸性锌(xin)锰电池的5倍左右;
它(ta)的低温放电(dian)性能(neng)也(ye)很(hen)好。充电(dian)次(ci)数在30次(ci)以内,一(yi)般10-20次(ci),需要特别充电(dian)器,极为容易丧失充电(dian)能(neng)力。
该设计采用了Power Integrations的(de)(de)LinkSwitch系列(lie)产品LNK613DG。这种设计非常适合手机或类似的(de)(de)USB充电(dian)器应(ying)用,包括手机电(dian)池充电(dian)器、USB 充电(dian)器或任何(he)有恒压/恒流特性要(yao)求的(de)(de)应(ying)用。
在(zai)电(dian)路中(zhong),二极管D1至 D4对(dui)(dui)AC输入进(jin)(jin)行(xing)整流,电(dian)容C1和(he)C2对(dui)(dui)DC进(jin)(jin)行(xing)滤波(bo)。L1、C1和(he)C2组成一(yi)个π型(xing)滤波(bo)器,对(dui)(dui)差模传(chuan)导(dao)EMI噪声进(jin)(jin)行(xing)衰减(jian)。这些(xie)与Power Integrations的(de)变压器E-sheild?技术相(xiang)结合,使本设计能以充足的(de)裕量轻松满足EN55022 B级传(chuan)导(dao)EMI要求(qiu),且无需Y电(dian)容。防(fang)火、可(ke)熔、绕(rao)线式电(dian)阻RF1提供严重故障保护,并可(ke)限制(zhi)启(qi)动期间产生的(de)浪涌电(dian)流。
图(tu)1显(xian)示U1通过可选偏置电(dian)(dian)源实现(xian)供电(dian)(dian),这样可以(yi)将空载(zai)功耗降低到(dao)40 mW以(yi)下(xia)。旁路电(dian)(dian)容C4的值决定(ding)电(dian)(dian)缆压降补(bu)(bu)偿(chang)的数(shu)量。1μF的值对(dui)应于对(dui)一条0.3 Ω、24 AWG USB输出电(dian)(dian)缆的补(bu)(bu)偿(chang)。(10 μF电(dian)(dian)容对(dui)0.49 Ω、26 AWG USB输出电(dian)(dian)缆进行补(bu)(bu)偿(chang)。)
在恒压阶段(duan),输出(chu)电(dian)压通过(guo)开(kai)关控(kong)制进行调(diao)节(jie)。输出(chu)电(dian)压通过(guo)跳(tiao)过(guo)开(kai)关周期得以(yi)(yi)维(wei)持。通过(guo)调(diao)整使能(neng)与(yu)禁止(zhi)周期的(de)(de)比例,可以(yi)(yi)维(wei)持稳压。这也(ye)可以(yi)(yi)使转换器的(de)(de)效率(lv)在整个负载范(fan)围内得到(dao)优化。轻载(涓(juan)流(liu)(liu)充(chong)电(dian))条(tiao)件下,还会降低(di)电(dian)流(liu)(liu)限流(liu)(liu)点以(yi)(yi)减小变压器磁通密度,进而降低(di)音频噪音和开(kai)关损耗。随着(zhe)负载电(dian)流(liu)(liu)的(de)(de)增(zeng)大(da),电(dian)流(liu)(liu)限流(liu)(liu)点也(ye)将升高,跳(tiao)过(guo)的(de)(de)周期也(ye)越来(lai)越少。
当不再跳(tiao)过任何开(kai)关(guan)周期时(达到最(zui)大功率点),LinkSwitch-II内的控(kong)制器将切换到恒流(liu)(liu)模(mo)式。需要(yao)进一步提高负载电(dian)流(liu)(liu)时,输(shu)出电(dian)压将会随之下降(jiang)(jiang)。输(shu)出电(dian)压的下降(jiang)(jiang)反映在(zai)FB引(yin)脚电(dian)压上(shang)。作为对FB引(yin)脚电(dian)压下降(jiang)(jiang)的响应,开(kai)关(guan)频率将线性下降(jiang)(jiang),从而实现恒流(liu)(liu)输(shu)出。
D5、R2、R3和C3组成RCD-R箝位(wei)电路,用(yong)于限制漏感引起的(de)漏极(ji)(ji)电压尖峰。电阻R3拥有相对较大的(de)值,用(yong)于避免漏感引起的(de)漏极(ji)(ji)电压波形振荡,这样可(ke)以(yi)防止关断(duan)期间的(de)过(guo)度(du)振荡,从而(er)降低传导EMI。
二极(ji)管(guan)D7对次级进行整流,C7对其进行滤波。C6和R7可以(yi)共同限(xian)制D7上的(de)瞬态电(dian)(dian)(dian)压(ya)尖峰,并降低传导及(ji)辐射EMI。电(dian)(dian)(dian)阻R8和齐纳二极(ji)管(guan) VR1形(xing)成一个输出(chu)假负载(zai),可以(yi)确(que)(que)保空载(zai)时的(de)输出(chu)电(dian)(dian)(dian)压(ya)处于可接受的(de)限(xian)制范(fan)围(wei)内,并确(que)(que)保充电(dian)(dian)(dian)器(qi)从AC市电(dian)(dian)(dian)断开时电(dian)(dian)(dian)池不会完(wan)全放电(dian)(dian)(dian)。反馈电(dian)(dian)(dian)阻R5和R6设定(ding)最大工作频率(lv)与恒压(ya)阶段的(de)输出(chu)电(dian)(dian)(dian)压(ya)。
恒流(liu)源(yuan)(yuan)驱动(dong)电路负责驱动(dong)温(wen)度(du)传感器Pt1000,将其(qi)感知的(de)随温(wen)度(du)变化(hua)的(de)电阻信(xin)号转换成可(ke)测量的(de)电压信(xin)号。本系统中,所需恒流(liu)源(yuan)(yuan)要具(ju)有输出电流(liu)恒定(ding)(ding),温(wen)度(du)稳定(ding)(ding)性好,输出电阻很(hen)大,输出电流(liu)小于0.5 mA(Pt1000无自热(re)效应的(de)上限(xian)),负载一端(duan)接地,输出电流(liu)极性可(ke)改变等特(te)点(dian)。
由于温度对(dui)集(ji)(ji)成运(yun)(yun)放(fang)参(can)数影响不如对(dui)晶(jing)体(ti)管或场效应(ying)管参(can)数影响显著(zhu),由集(ji)(ji)成运(yun)(yun)放(fang)构(gou)成的(de)(de)恒(heng)流(liu)源具(ju)有稳定性更好、恒(heng)流(liu)性能更高的(de)(de)优点。尤其在负载一端需要接地的(de)(de)场合,获得(de)了广泛应(ying)用(yong)。所以采(cai)用(yong)图2所示的(de)(de)双运(yun)(yun)放(fang)恒(heng)流(liu)源。其中放(fang)大(da)器(qi)UA1构(gou)成加(jia)法(fa)器(qi),UA2构(gou)成跟(gen)随器(qi),UA1、UA2均选用(yong)低噪声、低失调、高开环增益双极(ji)性运(yun)(yun)算放(fang)大(da)器(qi)OP07。
设图2中参考电(dian)阻Rref上下两端的电(dian)位分别Va和Vb,Va即为同相加法器UA1的输出,当取电(dian)阻R1=R2,R3=R4时(shi),则Va=VREFx+Vb,故恒(heng)流源的输出电(dian)流就为:
由此可见该双运放恒流源具有以下显著特点:
负(fu)载可接地(di);
当运放为双(shuang)(shuang)电(dian)(dian)源(yuan)供电(dian)(dian)时,输出(chu)电(dian)(dian)流为双(shuang)(shuang)极性;
恒定电(dian)流(liu)大小(xiao)通过改变(bian)输(shu)入参考基准VREF或(huo)调整参考电(dian)阻Rref0的(de)大小(xiao)来实现,很容易得到稳定的(de)小(xiao)电(dian)流(liu)和补偿校(xiao)准。
由于电(dian)(dian)阻(zu)(zu)的(de)(de)(de)失配(pei),参考电(dian)(dian)阻(zu)(zu)Rref0的(de)(de)(de)两端(duan)电(dian)(dian)压(ya)将(jiang)会(hui)受(shou)到其驱动负载的(de)(de)(de)端(duan)电(dian)(dian)压(ya)Vb的(de)(de)(de)影响。同时由于是(shi)恒流(liu)源(yuan),Vb肯(ken)定会(hui)随负载的(de)(de)(de)变化(hua)而(er)变化(hua),从而(er)就(jiu)会(hui)影响恒流(liu)源(yuan)的(de)(de)(de)稳定性。显然这对高精(jing)度的(de)(de)(de)恒流(liu)源(yuan)是(shi)不能接受(shou)的(de)(de)(de)。所以R1,R2,R3,R4这4个电(dian)(dian)阻(zu)(zu)的(de)(de)(de)选(xuan)取原则是(shi)失配(pei)要尽量的(de)(de)(de)小(xiao),且每对电(dian)(dian)阻(zu)(zu)的(de)(de)(de)失配(pei)大(da)小(xiao)方向要一(yi)致。实际(ji)中,可以对大(da)量同一(yi)批次的(de)(de)(de)精(jing)密电(dian)(dian)阻(zu)(zu)进行筛选(xuan),选(xuan)出其中阻(zu)(zu)值接近的(de)(de)(de)4个电(dian)(dian)阻(zu)(zu)。
研制仪器需要一(yi)(yi)个(ge)能在0到3兆欧姆电阻上产生1MA电流的恒流源,用UC3845结(jie)合12V蓄电池设计了一(yi)(yi)个(ge),变(bian)压(ya)器采用彩(cai)色(se)电视机高(gao)压(ya)包(bao),其中L1用漆包(bao)线在原(yuan)高(gao)压(ya)包(bao)磁心上绕24匝,L3借助原(yuan)来高(gao)压(ya)包(bao)的一(yi)(yi)个(ge)线圈,L2借助高(gao)压(ya)包(bao)的高(gao)压(ya)部分。L3和LM393构成限(xian)压(ya)电路,限(xian)制输(shu)出电压(ya)过高(gao),调节(jie)R10 可以调节(jie)开(kai)路输(shu)出电压(ya)。
联系方(fang)式:邹先生(sheng)
联系电话:0755-83888366-8022
手机:18123972950
QQ:2880195519
联系(xi)地址(zhi):深圳市福田区(qu)车公庙天安数码城天吉大厦CD座5C1
请(qing)搜(sou)微信公众(zhong)号:“KIA半(ban)导体”或扫一(yi)扫下图“关(guan)注”官方(fang)微信公众(zhong)号
请“关注”官(guan)方微信公众号(hao):提(ti)供(gong) MOS管 技术帮助(zhu)