一、電路原理

　　如圖所示，該充電器屬于電容限流式無電源變壓器恒流充電器。220V交(jiao)流(liu)(liu)電(dian)(dian)(dian)經K1～K4及(ji)其相應(ying)阻(zu)容元件組(zu)成的(de)4條并(bing)列支路選擇(ze)或組(zu)合，再經整流(liu)(liu)堆(dui)D整流(liu)(liu)后(hou)，通(tong)過電(dian)(dian)(dian)流(liu)(liu)表A，給蓄電(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)。在充(chong)電(dian)(dian)(dian)過程中，由(you)于(yu)回路中蓄電(dian)(dian)(dian)池兩端(duan)電(dian)(dian)(dian)壓的(de)變(bian)(bian)化(hua)量相對于(yu)220V交(jiao)流(liu)(liu)電(dian)(dian)(dian)壓來說很小，電(dian)(dian)(dian)容兩端(duan)的(de)電(dian)(dian)(dian)壓降(jiang)幾乎可認為是(shi)不變(bian)(bian)的(de)，所以，通(tong)過電(dian)(dian)(dian)容器的(de)電(dian)(dian)(dian)流(liu)(liu)也是(shi)不變(bian)(bian)的(de)，通(tong)過蓄電(dian)(dian)(dian)池內部的(de)充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)自然(ran)也是(shi)恒定的(de)。

　　圖中，L為220V交流電源指示燈，R1、R2、R3、R4分別是電容器C1、C2、C3、C4的泄放電阻，在不用充電器時(shi)，能及時(shi)將電(dian)(dian)(dian)容器(qi)上積存的(de)電(dian)(dian)(dian)荷放(fang)掉；K1、K2、K3、K4是(shi)(shi)支路(lu)控(kong)制開(kai)關(guan)，通過開(kai)關(guan)通斷控(kong)制可(ke)以決定支路(lu)是(shi)(shi)否并入電(dian)(dian)(dian)路(lu)；R5、LED組成空(kong)載(zai)報警指(zhi)示電(dian)(dian)(dian)路(lu)(為了安全(quan)，充電(dian)(dian)(dian)器(qi)不(bu)可(ke)在空(kong)載(zai)狀態下插(cha)入220V交流電(dian)(dian)(dian)源)，LED亮時(shi)，說明空(kong)載(zai)。電(dian)(dian)(dian)流表(biao)(biao)A指(zhi)示充電(dian)(dian)(dian)電(dian)(dian)(dian)流的(de)大小(xiao)：電(dian)(dian)(dian)壓表(biao)(biao)V指(zhi)示蓄電(dian)(dian)(dian)池兩端(duan)的(de)電(dian)(dian)(dian)壓(為防止(zhi)空(kong)載(zai)時(shi)電(dian)(dian)(dian)壓高燒壞電(dian)(dian)(dian)壓表(biao)(biao)，電(dian)(dian)(dian)壓表(biao)(biao)的(de)接入與否受(shou)開(kai)關(guan)K5的(de)控(kong)制)。

　　二、電路設計

　　該(gai)(gai)充(chong)電(dian)(dian)(dian)(dian)器的(de)(de)(de)(de)(de)限流(liu)(liu)電(dian)(dian)(dian)(dian)容(rong)器容(rong)量(liang)越(yue)大，容(rong)抗越(yue)小(xiao)，充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)越(yue)大。反之，充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)越(yue)小(xiao)。根(gen)據該(gai)(gai)原(yuan)理，可(ke)采用(yong)調整并聯電(dian)(dian)(dian)(dian)容(rong)的(de)(de)(de)(de)(de)方法(fa)來達到調整充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)大小(xiao)的(de)(de)(de)(de)(de)目的(de)(de)(de)(de)(de)。以汽車(che)、摩托車(che)、電(dian)(dian)(dian)(dian)動自(zi)行車(che)常用(yong)的(de)(de)(de)(de)(de)蓄電(dian)(dian)(dian)(dian)池為(wei)例，該(gai)(gai)充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)路設置了相(xiang)鄰級差為(wei)1A的(de)(de)(de)(de)(de)1～15A的(de)(de)(de)(de)(de)15級可(ke)調充(chong)電(dian)(dian)(dian)(dian)，通過(guo)四條支(zhi)路的(de)(de)(de)(de)(de)不同并聯組合實現對(dui)畜電(dian)(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)(de)(de)(de)調整。

　　由純電(dian)(dian)容交流(liu)(liu)(liu)電(dian)(dian)路中(zhong)(zhong)(圖(tu)中(zhong)(zhong)各分流(liu)(liu)(liu)電(dian)(dian)阻的(de)(de)(de)(de)分流(liu)(liu)(liu)很(hen)小，可忽略不計)電(dian)(dian)壓(ya)、電(dian)(dian)流(liu)(liu)(liu)、容抗之間的(de)(de)(de)(de)關系得：I=U／Xc=2πfcU=2×3．14×50×210C=65940C(式中(zhong)(zhong)，Xc表(biao)示電(dian)(dian)容器的(de)(de)(de)(de)容抗，其(qi)(qi)(qi)(qi)單(dan)位(wei)為(wei)(wei)(wei)歐姆；U表(biao)示電(dian)(dian)容器兩(liang)端(duan)的(de)(de)(de)(de)電(dian)(dian)壓(ya)，其(qi)(qi)(qi)(qi)單(dan)位(wei)為(wei)(wei)(wei)伏(fu)特(te)，其(qi)(qi)(qi)(qi)值為(wei)(wei)(wei)：交流(liu)(liu)(liu)電(dian)(dian)源的(de)(de)(de)(de)總電(dian)(dian)壓(ya)220V-蓄電(dian)(dian)池(chi)放電(dian)(dian)的(de)(de)(de)(de)下限電(dian)(dian)壓(ya)10V=210V；C表(biao)示電(dian)(dian)容器的(de)(de)(de)(de)容量，其(qi)(qi)(qi)(qi)單(dan)位(wei)為(wei)(wei)(wei)法拉：f表(biao)示交流(liu)(liu)(liu)電(dian)(dian)的(de)(de)(de)(de)頻率，其(qi)(qi)(qi)(qi)單(dan)位(wei)為(wei)(wei)(wei)赫茲(zi)，我國(guo)公(gong)共電(dian)(dian)網的(de)(de)(de)(de)頻率為(wei)(wei)(wei)50赫茲(zi)；I表(biao)示通過電(dian)(dian)容器的(de)(de)(de)(de)電(dian)(dian)流(liu)(liu)(liu)，其(qi)(qi)(qi)(qi)單(dan)位(wei)為(wei)(wei)(wei)安培(pei)；π取3．14)。

　　由以上(shang)計(ji)算結(jie)果(guo)可(ke)(ke)知，當電(dian)容器C取(qu)(qu)15微(wei)(wei)(wei)法(fa)(即(ji)0．000015法(fa)拉(la))時，I=65940C=65940×0．000015≈1(A)。C1=15微(wei)(wei)(wei)法(fa)、C2=30微(wei)(wei)(wei)法(fa)、C3=60微(wei)(wei)(wei)法(fa)、C4=120微(wei)(wei)(wei)法(fa)，對應的(de)(de)各支(zhi)(zhi)路(lu)(lu)電(dian)流分別為(wei)(wei)1A、2A、4A、8A。通過各控(kong)制(zhi)開關將(jiang)以上(shang)四(si)個電(dian)容器進行適當的(de)(de)并聯(lian)(lian)(lian)組(zu)(zu)合(he)便(bian)可(ke)(ke)得(de)(de)到1A、2A、3A……15A的(de)(de)15組(zu)(zu)可(ke)(ke)調(diao)充電(dian)電(dian)流。如(ru)(ru)果(guo)想將(jiang)電(dian)流調(diao)得(de)(de)更精細些(xie)，可(ke)(ke)增加(jia)并聯(lian)(lian)(lian)支(zhi)(zhi)路(lu)(lu)。如(ru)(ru)增加(jia)7．5微(wei)(wei)(wei)法(fa)支(zhi)(zhi)路(lu)(lu)可(ke)(ke)得(de)(de)到相鄰(lin)級(ji)(ji)(ji)差(cha)為(wei)(wei)0．5A的(de)(de)0．5A～15．5A的(de)(de)31級(ji)(ji)(ji)可(ke)(ke)調(diao)充電(dian)控(kong)制(zhi)系統，上(shang)述各支(zhi)(zhi)路(lu)(lu)電(dian)容器的(de)(de)容量若(ruo)只(zhi)取(qu)(qu)其十分之一，便(bian)可(ke)(ke)得(de)(de)到相鄰(lin)級(ji)(ji)(ji)差(cha)為(wei)(wei)O．1A的(de)(de)0．1～1．5A的(de)(de)15級(ji)(ji)(ji)可(ke)(ke)調(diao)并聯(lian)(lian)(lian)組(zu)(zu)合(he)充電(dian)控(kong)制(zhi)系統；若(ruo)只(zhi)取(qu)(qu)其容量的(de)(de)百分之一，便(bian)可(ke)(ke)得(de)(de)到相鄰(lin)級(ji)(ji)(ji)差(cha)為(wei)(wei)140mA的(de)(de)15級(ji)(ji)(ji)可(ke)(ke)調(diao)并聯(lian)(lian)(lian)組(zu)(zu)合(he)充電(dian)控(kong)制(zhi)系統。

　　三、制作方法

　　指示燈L應選(xuan)用(yong)(yong)(yong)(yong)(yong)額定工(gong)作電(dian)壓(ya)為220V的(de)(de)(de)(de)體積較小(xiao)些的(de)(de)(de)(de)燈泡，也(ye)可以用(yong)(yong)(yong)(yong)(yong)10kΩ的(de)(de)(de)(de)電(dian)阻和一個(ge)小(xiao)功率(lv)發光二(er)(er)極管串聯(lian)代替(ti)；控制(zhi)開(kai)關(guan)K1、K2、K3、K4應分別(bie)選(xuan)用(yong)(yong)(yong)(yong)(yong)額定工(gong)作電(dian)流(liu)不(bu)(bu)小(xiao)于1．5A、3A、6A、12A的(de)(de)(de)(de)；電(dian)容器C1、C2、C3、C4均選(xuan)用(yong)(yong)(yong)(yong)(yong)耐壓(ya)不(bu)(bu)小(xiao)于400V規(gui)格的(de)(de)(de)(de)；泄(xie)放(fang)電(dian)阻R1、R2、R3、R4均選(xuan)用(yong)(yong)(yong)(yong)(yong)220kΩ，1／2W規(gui)格的(de)(de)(de)(de)；整(zheng)流(liu)堆D應選(xuan)用(yong)(yong)(yong)(yong)(yong)額定工(gong)作電(dian)流(liu)不(bu)(bu)小(xiao)于50A，耐壓(ya)不(bu)(bu)小(xiao)于400V規(gui)格的(de)(de)(de)(de)；電(dian)流(liu)表A選(xuan)用(yong)(yong)(yong)(yong)(yong)量(liang)程為20A或30A規(gui)格的(de)(de)(de)(de)直(zhi)流(liu)電(dian)流(liu)表；電(dian)壓(ya)表V應選(xuan)用(yong)(yong)(yong)(yong)(yong)量(liang)程為50V規(gui)格的(de)(de)(de)(de)直(zhi)流(liu)電(dian)壓(ya)表；R5選(xuan)用(yong)(yong)(yong)(yong)(yong)10kΩ／6W的(de)(de)(de)(de)電(dian)阻；LED選(xuan)用(yong)(yong)(yong)(yong)(yong)普(pu)通小(xiao)功率(lv)發光二(er)(er)極管；K5選(xuan)用(yong)(yong)(yong)(yong)(yong)普(pu)通按鍵式開(kai)關(guan)，工(gong)作電(dian)流(liu)大小(xiao)不(bu)(bu)作要求。將控制(zhi)開(kai)關(guan)K1