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(lu)原理　　如(ru)圖所示，該(gai)充電(dian)(dian)(dian)(dian)器(qi)屬于(yu)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)限流(liu)式無電(dian)(dian)(dian)(dian)源變(bian)壓(ya)器(qi)恒(heng)流(liu)充電(dian)(dian)(dian)(dian)器(qi)。220V交流(liu)電(dian)(dian)(dian)(dian)經K1～K4及其(qi)相應阻容(rong)(rong)(rong)元(yuan)件組成的4條(tiao)并列支路(lu)選擇或組合(he)，再經整流(liu)堆(dui)D整流(liu)后，通(tong)(tong)過電(dian)(dian)(dian)(dian)流(liu)表A，給蓄電(dian)(dian)(dian)(dian)池充電(dian)(dian)(dian)(dian)。在充電(dian)(dian)(dian)(dian)過程中(zhong)，由(you)于(yu)回路(lu)中(zhong)蓄電(dian)(dian)(dian)(dian)池兩(liang)端電(dian)(dian)(dian)(dian)的變(bian)化量相對于(yu)220V交流(liu)電(dian)(dian)(dian)(dian)壓(ya)來說(shuo)很小(xiao)，電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)兩(liang)端的電(dian)(dian)(dian)(dian)壓(ya)降幾(ji)乎可(ke)認為是不(bu)變(bian)的，所以，通(tong)(tong)過電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)器(qi)的電(dian)(dian)(dian)(dian)流(liu)也是不(bu)變(bian)的，通(tong)(tong)過蓄電(dian)(dian)(dian)(dian)池內部的充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)自然也是恒(heng)定的。 　　

     L為220V交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)指示(shi)燈(deng)，R1、R2、R3、R4分別是電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容器C1、C2、C3、C4的(de)泄(xie)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻，在不用(yong)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器時(shi)，能及時(shi)將電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容器上積存(cun)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷放掉(diao)；K1、K2、K3、K4是支(zhi)路(lu)控(kong)制開(kai)關，通過開(kai)關通斷(duan)控(kong)制可(ke)(ke)以決定支(zhi)路(lu)是否并入(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)；R5、LED組成空(kong)(kong)載(zai)報警指示(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(為了安全，充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器不可(ke)(ke)在空(kong)(kong)載(zai)狀態下插(cha)入(ru)220V交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan))，LED亮時(shi)，說明(ming)空(kong)(kong)載(zai)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)表(biao)(biao)A指示(shi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的(de)大小：電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)(biao)V指示(shi)蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池兩端的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(為防止空(kong)(kong)載(zai)時(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)高燒壞電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)(biao)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)(biao)的(de)接入(ru)與否受開(kai)關K5的(de)控(kong)制)。

　　二、電路設計　　該充電器的(de)(de)限流(liu)電(dian)(dian)(dian)(dian)(dian)容器容量越(yue)(yue)(yue)大(da)，容抗越(yue)(yue)(yue)小(xiao)，充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)越(yue)(yue)(yue)大(da)。反之，充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)越(yue)(yue)(yue)小(xiao)。根據該(gai)原(yuan)理(li)，可(ke)(ke)采用調(diao)(diao)整(zheng)并聯電(dian)(dian)(dian)(dian)(dian)容的(de)(de)方法來(lai)達到調(diao)(diao)整(zheng)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)大(da)小(xiao)的(de)(de)目的(de)(de)。以汽車(che)、摩托車(che)、電(dian)(dian)(dian)(dian)(dian)動自行車(che)常用的(de)(de)蓄電(dian)(dian)(dian)(dian)(dian)池為(wei)例，該(gai)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)路(lu)設置了相鄰級差為(wei)1A的(de)(de)1～15A的(de)(de)15級可(ke)(ke)調(diao)(diao)充(chong)電(dian)(dian)(dian)(dian)(dian)，通過(guo)四條支路(lu)的(de)(de)不(bu)同并聯組合實現(xian)對畜電(dian)(dian)(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)的(de)(de)調(diao)(diao)整(zheng)。

　　由純電(dian)(dian)(dian)容交(jiao)流(liu)電(dian)(dian)(dian)路中(圖中各分(fen)流(liu)電(dian)(dian)(dian)阻的(de)(de)分(fen)流(liu)很(hen)小，可(ke)忽略不計)電(dian)(dian)(dian)壓、電(dian)(dian)(dian)流(liu)、容抗之間的(de)(de)關系得：I=U／Xc=2πfcU=2×3．14×50×210C=65940C(式中，Xc表(biao)(biao)示(shi)(shi)電(dian)(dian)(dian)容器(qi)(qi)的(de)(de)容抗，其單(dan)位為(wei)歐姆；U表(biao)(biao)示(shi)(shi)電(dian)(dian)(dian)容器(qi)(qi)兩端的(de)(de)電(dian)(dian)(dian)壓，其單(dan)位為(wei)伏特，其值為(wei)：交(jiao)流(liu)電(dian)(dian)(dian)源的(de)(de)總電(dian)(dian)(dian)壓220V-蓄(xu)電(dian)(dian)(dian)池放電(dian)(dian)(dian)的(de)(de)下限(xian)電(dian)(dian)(dian)壓10V=210V；C表(biao)(biao)示(shi)(shi)電(dian)(dian)(dian)容器(qi)(qi)的(de)(de)容量，其單(dan)位為(wei)法拉：f表(biao)(biao)示(shi)(shi)交(jiao)流(liu)電(dian)(dian)(dian)的(de)(de)頻率(lv)，其單(dan)位為(wei)赫茲，我國公共電(dian)(dian)(dian)網的(de)(de)頻率(lv)為(wei)50赫茲；I表(biao)(biao)示(shi)(shi)通過電(dian)(dian)(dian)容器(qi)(qi)的(de)(de)電(dian)(dian)(dian)流(liu)，其單(dan)位為(wei)安(an)培；π取3．14)。

　　由以(yi)(yi)上(shang)(shang)計算結果可知，當電(dian)(dian)(dian)容(rong)器C取15微(wei)(wei)(wei)法(即(ji)0．000015法拉)時，I=65940C=65940×0．000015≈1(A)。C1=15微(wei)(wei)(wei)法、C2=30微(wei)(wei)(wei)法、C3=60微(wei)(wei)(wei)法、C4=120微(wei)(wei)(wei)法，對應的(de)(de)各(ge)支路電(dian)(dian)(dian)流分別為(wei)1A、2A、4A、8A。通過各(ge)控制開關將(jiang)以(yi)(yi)上(shang)(shang)四個電(dian)(dian)(dian)容(rong)器進(jin)行適當的(de)(de)并聯組合便可得(de)到(dao)(dao)1A、2A、3A……15A的(de)(de)15組可調(diao)充(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流。如果想將(jiang)電(dian)(dian)(dian)流調(diao)得(de)更(geng)精細(xi)些(xie)，可增加并聯支路。如增加7．5微(wei)(wei)(wei)法支路可得(de)到(dao)(dao)相鄰(lin)級(ji)(ji)差(cha)為(wei)0．5A的(de)(de)0．5A～15．5A的(de)(de)31級(ji)(ji)可調(diao)充(chong)(chong)(chong)電(dian)(dian)(dian)控制系(xi)(xi)統(tong)，上(shang)(shang)述各(ge)支路電(dian)(dian)(dian)容(rong)器的(de)(de)容(rong)量若(ruo)只(zhi)取其(qi)十分之(zhi)一，便可得(de)到(dao)(dao)相鄰(lin)級(ji)(ji)差(cha)為(wei)O．1A的(de)(de)0．1～1．5A的(de)(de)15級(ji)(ji)可調(diao)并聯組合充(chong)(chong)(chong)電(dian)(dian)(dian)控制系(xi)(xi)統(tong)；若(ruo)只(zhi)取其(qi)容(rong)量的(de)(de)百分之(zhi)一，便可得(de)到(dao)(dao)相鄰(lin)級(ji)(ji)差(cha)為(wei)140mA的(de)(de)15級(ji)(ji)可調(diao)并聯組合充(chong)(chong)(chong)電(dian)(dian)(dian)控制系(xi)(xi)統(tong)。

　　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)；電(dian)(dian)(dian)(dian)(dian)容器C1、C2、C3、C4均選(xuan)用(yong)耐壓不(bu)小(xiao)于400V規(gui)(gui)格(ge)的(de)(de)；泄放電(dian)(dian)(dian)(dian)(dian)阻R1、R2、R3、R4均選(xuan)用(yong)220kΩ，1／2W規(gui)(gui)格(ge)的(de)(de)；整流(liu)(liu)堆D應(ying)選(xuan)用(yong)額定工作電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)不(bu)小(xiao)于50A，耐壓不(bu)小(xiao)于400V規(gui)(gui)格(ge)的(de)(de)；電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)表A選(xuan)用(yong)量(liang)程為(wei)(wei)20A或30A規(gui)(gui)格(ge)的(de)(de)直流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)表；電(dian)(dian)(dian)(dian)(dian)壓表V應(ying)選(xuan)用(yong)量(liang)程為(wei)(wei)50V規(gui)(gui)格(ge)的(de)(de)直流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)壓表；R5選(xuan)用(yong)10kΩ／6W的(de)(de)電(dian)(dian)(dian)(dian)(dian)阻；LED選(xuan)用(yong)普通小(xiao)功率(lv)發光(guang)二極管；K5選(xuan)用(yong)普通按鍵式開關(guan)，工作電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)大小(xiao)不(bu)作要求(qiu)。將控制開關(guan)K1、K2、K3、K4并排(pai)裝在(zai)機殼(ke)面(mian)板上適當的(de)(de)位置，并在(zai)K1、K2、K3、K4的(de)(de)位置旁(pang)邊分(fen)別標注上1A、2A、4A、8A的(de)(de)字(zi)樣，以便控制計算調整。蓄(xu)電(dian)(dian)(dian)(dian)(dian)池接線柱的(de)(de)工作電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)不(bu)小(xiao)于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(wei)了人身安全(quan)，充電(dian)(dian)時(shi)應(ying)嚴(yan)格照(zhao)下(xia)列(lie)程序(xu)進(jin)行操(cao)作：　　1．檢查各個開(kai)關應(ying)處于斷(duan)開(kai)狀態(tai)，將(jiang)蓄(xu)電(dian)(dian)池的(de)正、負極(ji)與(yu)接(jie)(jie)(jie)線柱連接(jie)(jie)(jie)可靠，然后(hou)閉合K5，電(dian)(dian)壓表指(zhi)示出蓄(xu)電(dian)(dian)池兩端的(de)電(dian)(dian)壓。　　2．將(jiang)電(dian)(dian)源插頭插入220V交流電(dian)(dian)源，接(jie)(jie)(jie)通(tong)K1，此(ci)時(shi)，觀(guan)察電(dian)(dian)源指(zhi)示燈亮，空載報警指(zhi)示發光(guang)二極(ji)管不應(ying)亮。若發光(guang)二極(ji)管亮，說明蓄(xu)電(dian)(dian)池正、負極(ji)與(yu)充電(dian)(dian)器接(jie)(jie)(jie)線柱之(zhi)間接(jie)(jie)(jie)觸不良，應(ying)除(chu)掉接(jie)(jie)(jie)點(dian)之(zhi)間的(de)臟(zang)物后(hou)再進(jin)行連接(jie)(jie)(jie)。　　3．根據蓄(xu)電(dian)(dian)池對充電(dian)(dian)電(dian)(dian)流的(de)要(yao)求(qiu)，選擇合適的(de)控制(zhi)開(kai)關接(jie)(jie)(jie)通(tong)并聯調(diao)整充電(dian)(dian)電(dian)(dian)流，充電(dian)(dian)電(dian)(dian)流數(shu)值為(wei)接(jie)(jie)(jie)通(tong)的(de)開(kai)關電(dian)(dian)流數(shu)之(zhi)和。

　　該充(chong)(chong)電器的(de)唯(wei)一缺陷是(shi)，不具備充(chong)(chong)滿電后(hou)自動停(ting)充(chong)(chong)的(de)功能。因各種蓄電池(chi)的(de)電壓及容量都不一樣，讀者應根據不同蓄電池(chi)的(de)要求決(jue)定(ding)充(chong)(chong)電的(de)電流和充(chong)(chong)電時間，通過電壓表監視(shi)充(chong)(chong)電程度。