本文介紹一款電路簡單、性能可靠的多用恒流充電器。

　　一、電(dian)(dian)(dian)(dian)路原理　　如(ru)圖所示(shi)，該充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器屬(shu)于(yu)電(dian)(dian)(dian)(dian)容限流式無電(dian)(dian)(dian)(dian)源變(bian)壓(ya)(ya)器恒流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器。220V交流電(dian)(dian)(dian)(dian)經(jing)K1～K4及其(qi)相(xiang)應阻容元件組成的(de)4條并(bing)列支(zhi)路選擇或(huo)組合，再經(jing)整流堆D整流后，通(tong)過(guo)(guo)電(dian)(dian)(dian)(dian)流表A，給蓄電(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)。在充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)過(guo)(guo)程(cheng)中(zhong)，由于(yu)回(hui)路中(zhong)蓄電(dian)(dian)(dian)(dian)池(chi)兩端電(dian)(dian)(dian)(dian)的(de)變(bian)化量相(xiang)對于(yu)220V交流電(dian)(dian)(dian)(dian)壓(ya)(ya)來(lai)說很小(xiao)，電(dian)(dian)(dian)(dian)容兩端的(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)降幾乎(hu)可認為是不(bu)變(bian)的(de)，所以，通(tong)過(guo)(guo)電(dian)(dian)(dian)(dian)容器的(de)電(dian)(dian)(dian)(dian)流也是不(bu)變(bian)的(de)，通(tong)過(guo)(guo)蓄電(dian)(dian)(dian)(dian)池(chi)內部的(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流自然也是恒定的(de)。 　　

     L為220V交流(liu)(liu)電(dian)(dian)(dian)(dian)源(yuan)指示(shi)燈(deng)，R1、R2、R3、R4分別是(shi)電(dian)(dian)(dian)(dian)容器(qi)(qi)C1、C2、C3、C4的(de)(de)(de)泄放電(dian)(dian)(dian)(dian)阻，在不用充電(dian)(dian)(dian)(dian)器(qi)(qi)時(shi)，能及時(shi)將電(dian)(dian)(dian)(dian)容器(qi)(qi)上積存的(de)(de)(de)電(dian)(dian)(dian)(dian)荷放掉；K1、K2、K3、K4是(shi)支(zhi)路(lu)控制(zhi)(zhi)開(kai)關(guan)(guan)(guan)，通過開(kai)關(guan)(guan)(guan)通斷控制(zhi)(zhi)可(ke)(ke)以決(jue)定支(zhi)路(lu)是(shi)否并入電(dian)(dian)(dian)(dian)路(lu)；R5、LED組成空(kong)載(zai)(zai)報(bao)警指示(shi)電(dian)(dian)(dian)(dian)路(lu)(為了安全，充電(dian)(dian)(dian)(dian)器(qi)(qi)不可(ke)(ke)在空(kong)載(zai)(zai)狀態下(xia)插入220V交流(liu)(liu)電(dian)(dian)(dian)(dian)源(yuan))，LED亮時(shi)，說(shuo)明空(kong)載(zai)(zai)。電(dian)(dian)(dian)(dian)流(liu)(liu)表(biao)(biao)(biao)A指示(shi)充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)(de)大小：電(dian)(dian)(dian)(dian)壓(ya)表(biao)(biao)(biao)V指示(shi)蓄電(dian)(dian)(dian)(dian)池(chi)兩端的(de)(de)(de)電(dian)(dian)(dian)(dian)壓(ya)(為防止空(kong)載(zai)(zai)時(shi)電(dian)(dian)(dian)(dian)壓(ya)高燒(shao)壞電(dian)(dian)(dian)(dian)壓(ya)表(biao)(biao)(biao)，電(dian)(dian)(dian)(dian)壓(ya)表(biao)(biao)(biao)的(de)(de)(de)接入與否受(shou)開(kai)關(guan)(guan)(guan)K5的(de)(de)(de)控制(zhi)(zhi))。

　　二、電路設計　　該充電器的(de)(de)限流(liu)電(dian)(dian)(dian)容(rong)器容(rong)量越大(da)(da)，容(rong)抗越小，充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)越大(da)(da)。反之(zhi)，充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)越小。根據(ju)該原理，可采用調整并聯電(dian)(dian)(dian)容(rong)的(de)(de)方法(fa)來達到調整充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)大(da)(da)小的(de)(de)目的(de)(de)。以汽車(che)、摩托車(che)、電(dian)(dian)(dian)動自行車(che)常用的(de)(de)蓄電(dian)(dian)(dian)池(chi)為例，該充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)路設置(zhi)了相鄰級(ji)差為1A的(de)(de)1～15A的(de)(de)15級(ji)可調充(chong)(chong)電(dian)(dian)(dian)，通(tong)過四條支路的(de)(de)不同并聯組合實現對畜(chu)電(dian)(dian)(dian)池(chi)充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)的(de)(de)調整。

　　由純電(dian)(dian)(dian)(dian)(dian)容交流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)路中(zhong)(圖中(zhong)各分流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)阻的(de)(de)(de)分流(liu)(liu)很小，可忽略不(bu)計)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)、電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)、容抗之間(jian)的(de)(de)(de)關系得：I=U／Xc=2πfcU=2×3．14×50×210C=65940C(式中(zhong)，Xc表示電(dian)(dian)(dian)(dian)(dian)容器的(de)(de)(de)容抗，其(qi)單(dan)位為(wei)歐姆；U表示電(dian)(dian)(dian)(dian)(dian)容器兩端(duan)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，其(qi)單(dan)位為(wei)伏特，其(qi)值(zhi)為(wei)：交流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)源的(de)(de)(de)總電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)220V-蓄電(dian)(dian)(dian)(dian)(dian)池(chi)放電(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)下限電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)10V=210V；C表示電(dian)(dian)(dian)(dian)(dian)容器的(de)(de)(de)容量(liang)，其(qi)單(dan)位為(wei)法(fa)拉：f表示交流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)頻率，其(qi)單(dan)位為(wei)赫(he)茲(zi)，我國公(gong)共電(dian)(dian)(dian)(dian)(dian)網(wang)的(de)(de)(de)頻率為(wei)50赫(he)茲(zi)；I表示通過電(dian)(dian)(dian)(dian)(dian)容器的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)，其(qi)單(dan)位為(wei)安培；π取3．14)。

　　由以上(shang)計算結(jie)果可(ke)知，當電(dian)(dian)容(rong)(rong)(rong)器(qi)C取(qu)15微(wei)(wei)(wei)(wei)法(fa)(fa)(fa)(fa)(即0．000015法(fa)(fa)(fa)(fa)拉)時，I=65940C=65940×0．000015≈1(A)。C1=15微(wei)(wei)(wei)(wei)法(fa)(fa)(fa)(fa)、C2=30微(wei)(wei)(wei)(wei)法(fa)(fa)(fa)(fa)、C3=60微(wei)(wei)(wei)(wei)法(fa)(fa)(fa)(fa)、C4=120微(wei)(wei)(wei)(wei)法(fa)(fa)(fa)(fa)，對應的(de)各(ge)支(zhi)路電(dian)(dian)流分(fen)別為(wei)1A、2A、4A、8A。通過各(ge)控制開關將以上(shang)四個電(dian)(dian)容(rong)(rong)(rong)器(qi)進行適當的(de)并(bing)(bing)聯(lian)組(zu)合(he)便(bian)可(ke)得(de)到1A、2A、3A……15A的(de)15組(zu)可(ke)調(diao)(diao)充電(dian)(dian)電(dian)(dian)流。如果想(xiang)將電(dian)(dian)流調(diao)(diao)得(de)更精細些，可(ke)增(zeng)加并(bing)(bing)聯(lian)支(zhi)路。如增(zeng)加7．5微(wei)(wei)(wei)(wei)法(fa)(fa)(fa)(fa)支(zhi)路可(ke)得(de)到相鄰(lin)級(ji)(ji)差(cha)為(wei)0．5A的(de)0．5A～15．5A的(de)31級(ji)(ji)可(ke)調(diao)(diao)充電(dian)(dian)控制系統，上(shang)述(shu)各(ge)支(zhi)路電(dian)(dian)容(rong)(rong)(rong)器(qi)的(de)容(rong)(rong)(rong)量若只(zhi)取(qu)其(qi)十分(fen)之(zhi)一，便(bian)可(ke)得(de)到相鄰(lin)級(ji)(ji)差(cha)為(wei)O．1A的(de)0．1～1．5A的(de)15級(ji)(ji)可(ke)調(diao)(diao)并(bing)(bing)聯(lian)組(zu)合(he)充電(dian)(dian)控制系統；若只(zhi)取(qu)其(qi)容(rong)(rong)(rong)量的(de)百分(fen)之(zhi)一，便(bian)可(ke)得(de)到相鄰(lin)級(ji)(ji)差(cha)為(wei)140mA的(de)15級(ji)(ji)可(ke)調(diao)(diao)并(bing)(bing)聯(lian)組(zu)合(he)充電(dian)(dian)控制系統。

　　三、制作方法　　指示燈L應選用額定工作電壓為220V的體積較小些的燈泡，也可以用10kΩ的電阻和一個小功率發光二極管串聯代替；控制開關K1、K2、K3、K4應分別選用額定工作電流不小于1．5A、3A、6A、12A的；電(dian)容器(qi)C1、C2、C3、C4均選(xuan)用耐壓(ya)(ya)(ya)不小(xiao)于(yu)400V規格的；泄放電(dian)阻R1、R2、R3、R4均選(xuan)用220kΩ，1／2W規格的；整流(liu)堆D應選(xuan)用額定(ding)工作電(dian)流(liu)不小(xiao)于(yu)50A，耐壓(ya)(ya)(ya)不小(xiao)于(yu)400V規格的；電(dian)流(liu)表A選(xuan)用量(liang)程為(wei)20A或(huo)30A規格的直(zhi)流(liu)電(dian)流(liu)表；電(dian)壓(ya)(ya)(ya)表V應選(xuan)用量(liang)程為(wei)50V規格的直(zhi)流(liu)電(dian)壓(ya)(ya)(ya)表；R5選(xuan)用10kΩ／6W的電(dian)阻；LED選(xuan)用普通小(xiao)功(gong)率發光(guang)二極管；K5選(xuan)用普通按(an)鍵(jian)式(shi)開(kai)關，工作電(dian)流(liu)大小(xiao)不作要求。將控制開(kai)關K1、K2、K3、K4并排裝在機殼面板上適(shi)當的位置(zhi)(zhi)，并在K1、K2、K3、K4的位置(zhi)(zhi)旁邊分(fen)別標注上1A、2A、4A、8A的字樣，以便(bian)控制計算調整。蓄電(dian)池接線柱(zhu)的工作電(dian)流(liu)不小(xiao)于(yu)20A。

　　四、使用方法　　該充電器屬于無電源變壓器隔離式充電器，為了人身安全(quan)，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)應(ying)嚴(yan)格照(zhao)下(xia)列程序(xu)進(jin)行(xing)操作：　　1．檢查各個開關(guan)應(ying)處于斷(duan)開狀態，將蓄電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的(de)(de)(de)正、負極與(yu)接(jie)(jie)線柱連接(jie)(jie)可靠，然后閉合K5，電(dian)(dian)(dian)(dian)(dian)(dian)壓表(biao)指示(shi)出蓄電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)兩(liang)端的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓。　　2．將電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)插(cha)頭插(cha)入(ru)220V交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)，接(jie)(jie)通(tong)(tong)K1，此時(shi)，觀察(cha)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)指示(shi)燈亮(liang)(liang)，空(kong)載報警(jing)指示(shi)發光二極管(guan)(guan)不應(ying)亮(liang)(liang)。若發光二極管(guan)(guan)亮(liang)(liang)，說(shuo)明蓄電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)正、負極與(yu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器接(jie)(jie)線柱之間接(jie)(jie)觸(chu)不良，應(ying)除掉接(jie)(jie)點之間的(de)(de)(de)臟物后再進(jin)行(xing)連接(jie)(jie)。　　3．根據蓄電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)對充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)(de)要求，選擇(ze)合適的(de)(de)(de)控制開關(guan)接(jie)(jie)通(tong)(tong)并聯調整充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)數值(zhi)為接(jie)(jie)通(tong)(tong)的(de)(de)(de)開關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)數之和。

　　該充(chong)電(dian)(dian)(dian)(dian)(dian)器的(de)唯一缺陷是(shi)，不(bu)具備充(chong)滿電(dian)(dian)(dian)(dian)(dian)后自(zi)動(dong)停(ting)充(chong)的(de)功能。因各(ge)種蓄(xu)電(dian)(dian)(dian)(dian)(dian)池的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)及容量都(dou)不(bu)一樣，讀(du)者應根據不(bu)同(tong)蓄(xu)電(dian)(dian)(dian)(dian)(dian)池的(de)要求決定充(chong)電(dian)(dian)(dian)(dian)(dian)的(de)電(dian)(dian)(dian)(dian)(dian)流(liu)和充(chong)電(dian)(dian)(dian)(dian)(dian)時間(jian)，通(tong)過電(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)監(jian)視(shi)充(chong)電(dian)(dian)(dian)(dian)(dian)程度。