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)(dian)(dian)路原理　　如圖(tu)所示(shi)，該充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)屬于(yu)(yu)電(dian)(dian)(dian)(dian)(dian)(dian)容限流(liu)式無電(dian)(dian)(dian)(dian)(dian)(dian)源變壓(ya)器(qi)恒流(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)。220V交(jiao)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)經(jing)K1～K4及其相應阻容元件組成(cheng)的(de)4條并(bing)列(lie)支路選擇或(huo)組合，再(zai)經(jing)整(zheng)流(liu)堆D整(zheng)流(liu)后，通過電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)表(biao)A，給(gei)蓄電(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。在充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)過程(cheng)中，由于(yu)(yu)回路中蓄電(dian)(dian)(dian)(dian)(dian)(dian)池兩端電(dian)(dian)(dian)(dian)(dian)(dian)的(de)變化量相對(dui)于(yu)(yu)220V交(jiao)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)來說很小，電(dian)(dian)(dian)(dian)(dian)(dian)容兩端的(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)降幾(ji)乎可認為是不變的(de)，所以，通過電(dian)(dian)(dian)(dian)(dian)(dian)容器(qi)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)也是不變的(de)，通過蓄電(dian)(dian)(dian)(dian)(dian)(dian)池內(nei)部的(de)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)自然也是恒定的(de)。 　　

     L為(wei)220V交流(liu)電(dian)(dian)(dian)源指(zhi)示(shi)(shi)燈，R1、R2、R3、R4分(fen)別是(shi)電(dian)(dian)(dian)容器(qi)C1、C2、C3、C4的(de)泄放(fang)電(dian)(dian)(dian)阻，在(zai)不用(yong)充電(dian)(dian)(dian)器(qi)時，能及時將電(dian)(dian)(dian)容器(qi)上積(ji)存(cun)的(de)電(dian)(dian)(dian)荷放(fang)掉(diao)；K1、K2、K3、K4是(shi)支路(lu)控(kong)制(zhi)(zhi)開關，通(tong)過開關通(tong)斷控(kong)制(zhi)(zhi)可(ke)(ke)以決定支路(lu)是(shi)否(fou)并入電(dian)(dian)(dian)路(lu)；R5、LED組(zu)成(cheng)空(kong)(kong)載(zai)(zai)(zai)報警指(zhi)示(shi)(shi)電(dian)(dian)(dian)路(lu)(為(wei)了(le)安全(quan)，充電(dian)(dian)(dian)器(qi)不可(ke)(ke)在(zai)空(kong)(kong)載(zai)(zai)(zai)狀態下插入220V交流(liu)電(dian)(dian)(dian)源)，LED亮時，說明空(kong)(kong)載(zai)(zai)(zai)。電(dian)(dian)(dian)流(liu)表A指(zhi)示(shi)(shi)充電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)的(de)大小：電(dian)(dian)(dian)壓(ya)(ya)表V指(zhi)示(shi)(shi)蓄電(dian)(dian)(dian)池兩端(duan)的(de)電(dian)(dian)(dian)壓(ya)(ya)(為(wei)防止(zhi)空(kong)(kong)載(zai)(zai)(zai)時電(dian)(dian)(dian)壓(ya)(ya)高燒壞電(dian)(dian)(dian)壓(ya)(ya)表，電(dian)(dian)(dian)壓(ya)(ya)表的(de)接入與否(fou)受開關K5的(de)控(kong)制(zhi)(zhi))。

　　二、電路設計　　該充電器的(de)(de)限流(liu)電(dian)(dian)(dian)(dian)容器容量越大(da)，容抗越小(xiao)(xiao)(xiao)，充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)越大(da)。反(fan)之，充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)越小(xiao)(xiao)(xiao)。根據該原理，可(ke)(ke)采用調(diao)整并聯電(dian)(dian)(dian)(dian)容的(de)(de)方法來達(da)到調(diao)整充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)大(da)小(xiao)(xiao)(xiao)的(de)(de)目的(de)(de)。以汽車、摩(mo)托車、電(dian)(dian)(dian)(dian)動(dong)自行車常用的(de)(de)蓄電(dian)(dian)(dian)(dian)池(chi)為例，該充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)路(lu)設(she)置了(le)相鄰級差(cha)為1A的(de)(de)1～15A的(de)(de)15級可(ke)(ke)調(diao)充電(dian)(dian)(dian)(dian)，通過(guo)四條支路(lu)的(de)(de)不同并聯組合(he)實現對(dui)畜電(dian)(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)的(de)(de)調(diao)整。

　　由純電(dian)(dian)容(rong)(rong)交流(liu)電(dian)(dian)路(lu)中(zhong)(圖中(zhong)各分(fen)流(liu)電(dian)(dian)阻的(de)(de)分(fen)流(liu)很(hen)小，可忽(hu)略(lve)不計(ji))電(dian)(dian)壓(ya)、電(dian)(dian)流(liu)、容(rong)(rong)抗之間的(de)(de)關(guan)系得：I=U／Xc=2πfcU=2×3．14×50×210C=65940C(式中(zhong)，Xc表(biao)(biao)示電(dian)(dian)容(rong)(rong)器(qi)(qi)的(de)(de)容(rong)(rong)抗，其(qi)單位(wei)(wei)為(wei)歐姆；U表(biao)(biao)示電(dian)(dian)容(rong)(rong)器(qi)(qi)兩端(duan)的(de)(de)電(dian)(dian)壓(ya)，其(qi)單位(wei)(wei)為(wei)伏特，其(qi)值為(wei)：交流(liu)電(dian)(dian)源的(de)(de)總電(dian)(dian)壓(ya)220V-蓄(xu)電(dian)(dian)池放電(dian)(dian)的(de)(de)下限電(dian)(dian)壓(ya)10V=210V；C表(biao)(biao)示電(dian)(dian)容(rong)(rong)器(qi)(qi)的(de)(de)容(rong)(rong)量，其(qi)單位(wei)(wei)為(wei)法(fa)拉：f表(biao)(biao)示交流(liu)電(dian)(dian)的(de)(de)頻率，其(qi)單位(wei)(wei)為(wei)赫(he)(he)茲(zi)，我國公共電(dian)(dian)網的(de)(de)頻率為(wei)50赫(he)(he)茲(zi)；I表(biao)(biao)示通(tong)過電(dian)(dian)容(rong)(rong)器(qi)(qi)的(de)(de)電(dian)(dian)流(liu)，其(qi)單位(wei)(wei)為(wei)安培；π取3．14)。

　　由(you)以上(shang)(shang)計(ji)算結果(guo)可(ke)知，當電(dian)容(rong)器(qi)C取(qu)15微(wei)法(fa)(fa)(即0．000015法(fa)(fa)拉)時，I=65940C=65940×0．000015≈1(A)。C1=15微(wei)法(fa)(fa)、C2=30微(wei)法(fa)(fa)、C3=60微(wei)法(fa)(fa)、C4=120微(wei)法(fa)(fa)，對(dui)應(ying)的(de)各(ge)支(zhi)路(lu)(lu)電(dian)流分(fen)別(bie)為1A、2A、4A、8A。通過各(ge)控(kong)制(zhi)開關將(jiang)以上(shang)(shang)四(si)個電(dian)容(rong)器(qi)進行適當的(de)并聯(lian)組(zu)(zu)合(he)便可(ke)得(de)到(dao)1A、2A、3A……15A的(de)15組(zu)(zu)可(ke)調(diao)(diao)充電(dian)電(dian)流。如果(guo)想將(jiang)電(dian)流調(diao)(diao)得(de)更精細(xi)些，可(ke)增加(jia)并聯(lian)支(zhi)路(lu)(lu)。如增加(jia)7．5微(wei)法(fa)(fa)支(zhi)路(lu)(lu)可(ke)得(de)到(dao)相(xiang)鄰級(ji)差(cha)為0．5A的(de)0．5A～15．5A的(de)31級(ji)可(ke)調(diao)(diao)充電(dian)控(kong)制(zhi)系(xi)統，上(shang)(shang)述各(ge)支(zhi)路(lu)(lu)電(dian)容(rong)器(qi)的(de)容(rong)量若只(zhi)取(qu)其十分(fen)之(zhi)一(yi)，便可(ke)得(de)到(dao)相(xiang)鄰級(ji)差(cha)為O．1A的(de)0．1～1．5A的(de)15級(ji)可(ke)調(diao)(diao)并聯(lian)組(zu)(zu)合(he)充電(dian)控(kong)制(zhi)系(xi)統；若只(zhi)取(qu)其容(rong)量的(de)百分(fen)之(zhi)一(yi)，便可(ke)得(de)到(dao)相(xiang)鄰級(ji)差(cha)為140mA的(de)15級(ji)可(ke)調(diao)(diao)并聯(lian)組(zu)(zu)合(he)充電(dian)控(kong)制(zhi)系(xi)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(de)(de)(de)(de)(de)；電(dian)(dian)(dian)(dian)容器C1、C2、C3、C4均(jun)選(xuan)用耐壓(ya)不小于(yu)400V規(gui)格的(de)(de)(de)(de)(de)；泄放電(dian)(dian)(dian)(dian)阻(zu)R1、R2、R3、R4均(jun)選(xuan)用220kΩ，1／2W規(gui)格的(de)(de)(de)(de)(de)；整流(liu)堆D應(ying)選(xuan)用額定工(gong)(gong)作電(dian)(dian)(dian)(dian)流(liu)不小于(yu)50A，耐壓(ya)不小于(yu)400V規(gui)格的(de)(de)(de)(de)(de)；電(dian)(dian)(dian)(dian)流(liu)表(biao)A選(xuan)用量程為(wei)20A或30A規(gui)格的(de)(de)(de)(de)(de)直(zhi)流(liu)電(dian)(dian)(dian)(dian)流(liu)表(biao)；電(dian)(dian)(dian)(dian)壓(ya)表(biao)V應(ying)選(xuan)用量程為(wei)50V規(gui)格的(de)(de)(de)(de)(de)直(zhi)流(liu)電(dian)(dian)(dian)(dian)壓(ya)表(biao)；R5選(xuan)用10kΩ／6W的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)阻(zu)；LED選(xuan)用普通小功率發光二極管；K5選(xuan)用普通按鍵(jian)式開(kai)關(guan)，工(gong)(gong)作電(dian)(dian)(dian)(dian)流(liu)大小不作要求。將控制開(kai)關(guan)K1、K2、K3、K4并(bing)排(pai)裝在(zai)機殼面(mian)板上適當的(de)(de)(de)(de)(de)位置，并(bing)在(zai)K1、K2、K3、K4的(de)(de)(de)(de)(de)位置旁邊分別標注(zhu)上1A、2A、4A、8A的(de)(de)(de)(de)(de)字(zi)樣，以便控制計算調整。蓄電(dian)(dian)(dian)(dian)池接線柱的(de)(de)(de)(de)(de)工(gong)(gong)作電(dian)(dian)(dian)(dian)流(liu)不小于(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(le)人身安(an)全，充(chong)電(dian)(dian)(dian)時應(ying)嚴格照下列程序進行操作：　　1．檢查各個開關(guan)應(ying)處于斷開狀態，將(jiang)蓄(xu)電(dian)(dian)(dian)池(chi)的(de)(de)(de)正、負極與(yu)接(jie)(jie)線柱(zhu)連(lian)接(jie)(jie)可靠，然后閉合K5，電(dian)(dian)(dian)壓表指示(shi)出蓄(xu)電(dian)(dian)(dian)池(chi)兩(liang)端(duan)的(de)(de)(de)電(dian)(dian)(dian)壓。　　2．將(jiang)電(dian)(dian)(dian)源(yuan)(yuan)插頭插入220V交流電(dian)(dian)(dian)源(yuan)(yuan)，接(jie)(jie)通K1，此(ci)時，觀察電(dian)(dian)(dian)源(yuan)(yuan)指示(shi)燈亮(liang)，空載報警指示(shi)發光二極管不應(ying)亮(liang)。若(ruo)發光二極管亮(liang)，說明蓄(xu)電(dian)(dian)(dian)池(chi)正、負極與(yu)充(chong)電(dian)(dian)(dian)器接(jie)(jie)線柱(zhu)之間(jian)接(jie)(jie)觸不良，應(ying)除掉(diao)接(jie)(jie)點之間(jian)的(de)(de)(de)臟物后再(zai)進行連(lian)接(jie)(jie)。　　3．根據蓄(xu)電(dian)(dian)(dian)池(chi)對充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流的(de)(de)(de)要(yao)求，選擇合適(shi)的(de)(de)(de)控(kong)制開關(guan)接(jie)(jie)通并(bing)聯調整充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流，充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流數值為接(jie)(jie)通的(de)(de)(de)開關(guan)電(dian)(dian)(dian)流數之和。

　　該(gai)充(chong)電器的唯一(yi)缺陷是(shi)，不具備充(chong)滿電后自動停充(chong)的功能。因各(ge)種(zhong)蓄電池(chi)的電壓(ya)及容量都不一(yi)樣(yang)，讀者應根(gen)據(ju)不同蓄電池(chi)的要(yao)求決定(ding)充(chong)電的電流(liu)和充(chong)電時間，通(tong)過電壓(ya)表監視(shi)充(chong)電程度。