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)路(lu)(lu)原理　　如圖所(suo)示(shi)，該充(chong)電(dian)(dian)器屬于(yu)電(dian)(dian)容(rong)(rong)限流(liu)式無電(dian)(dian)源變壓器恒流(liu)充(chong)電(dian)(dian)器。220V交流(liu)電(dian)(dian)經K1～K4及其相應(ying)阻容(rong)(rong)元件組成的(de)(de)(de)4條并(bing)列支路(lu)(lu)選擇或(huo)組合，再經整流(liu)堆D整流(liu)后，通過電(dian)(dian)流(liu)表A，給蓄(xu)電(dian)(dian)池(chi)充(chong)電(dian)(dian)。在(zai)充(chong)電(dian)(dian)過程中，由于(yu)回路(lu)(lu)中蓄(xu)電(dian)(dian)池(chi)兩端(duan)電(dian)(dian)的(de)(de)(de)變化量相對于(yu)220V交流(liu)電(dian)(dian)壓來說很小，電(dian)(dian)容(rong)(rong)兩端(duan)的(de)(de)(de)電(dian)(dian)壓降幾乎可(ke)認為是不變的(de)(de)(de)，所(suo)以，通過電(dian)(dian)容(rong)(rong)器的(de)(de)(de)電(dian)(dian)流(liu)也是不變的(de)(de)(de)，通過蓄(xu)電(dian)(dian)池(chi)內部的(de)(de)(de)充(chong)電(dian)(dian)電(dian)(dian)流(liu)自然也是恒定的(de)(de)(de)。 　　

     L為(wei)(wei)220V交(jiao)流(liu)(liu)電(dian)(dian)(dian)源(yuan)指(zhi)示(shi)燈(deng)，R1、R2、R3、R4分別是電(dian)(dian)(dian)容(rong)器C1、C2、C3、C4的(de)(de)泄放電(dian)(dian)(dian)阻，在不(bu)用充電(dian)(dian)(dian)器時，能及(ji)時將(jiang)電(dian)(dian)(dian)容(rong)器上積存的(de)(de)電(dian)(dian)(dian)荷放掉；K1、K2、K3、K4是支路(lu)控(kong)制(zhi)開關(guan)，通過(guo)開關(guan)通斷控(kong)制(zhi)可以決(jue)定支路(lu)是否并入(ru)電(dian)(dian)(dian)路(lu)；R5、LED組成空載報(bao)警指(zhi)示(shi)電(dian)(dian)(dian)路(lu)(為(wei)(wei)了(le)安(an)全，充電(dian)(dian)(dian)器不(bu)可在空載狀態下插入(ru)220V交(jiao)流(liu)(liu)電(dian)(dian)(dian)源(yuan))，LED亮(liang)時，說明空載。電(dian)(dian)(dian)流(liu)(liu)表(biao)A指(zhi)示(shi)充電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)的(de)(de)大小(xiao)：電(dian)(dian)(dian)壓(ya)表(biao)V指(zhi)示(shi)蓄電(dian)(dian)(dian)池(chi)兩(liang)端的(de)(de)電(dian)(dian)(dian)壓(ya)(為(wei)(wei)防止空載時電(dian)(dian)(dian)壓(ya)高燒壞電(dian)(dian)(dian)壓(ya)表(biao)，電(dian)(dian)(dian)壓(ya)表(biao)的(de)(de)接(jie)入(ru)與否受開關(guan)K5的(de)(de)控(kong)制(zhi))。

　　二、電路設計　　該充電器的(de)(de)(de)限(xian)流(liu)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)器容(rong)(rong)量越大(da)，容(rong)(rong)抗越小，充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)越大(da)。反之，充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)越小。根據該(gai)原理，可(ke)采用調(diao)整并聯電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)的(de)(de)(de)方法來達(da)到調(diao)整充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)大(da)小的(de)(de)(de)目的(de)(de)(de)。以(yi)汽車(che)(che)、摩(mo)托車(che)(che)、電(dian)(dian)(dian)(dian)(dian)動自行車(che)(che)常用的(de)(de)(de)蓄(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)為例(li)，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1A的(de)(de)(de)1～15A的(de)(de)(de)15級可(ke)調(diao)充(chong)電(dian)(dian)(dian)(dian)(dian)，通過四條支路(lu)的(de)(de)(de)不同并聯組合(he)實現對畜(chu)電(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)的(de)(de)(de)調(diao)整。

　　由純電(dian)(dian)(dian)容交(jiao)(jiao)流電(dian)(dian)(dian)路中(zhong)(zhong)(圖中(zhong)(zhong)各分流電(dian)(dian)(dian)阻的(de)(de)分流很小，可忽略不計)電(dian)(dian)(dian)壓(ya)、電(dian)(dian)(dian)流、容抗之間的(de)(de)關系(xi)得(de)：I=U／Xc=2πfcU=2×3．14×50×210C=65940C(式中(zhong)(zhong)，Xc表示電(dian)(dian)(dian)容器(qi)的(de)(de)容抗，其(qi)(qi)(qi)單(dan)(dan)(dan)位(wei)為(wei)(wei)歐姆；U表示電(dian)(dian)(dian)容器(qi)兩端的(de)(de)電(dian)(dian)(dian)壓(ya)，其(qi)(qi)(qi)單(dan)(dan)(dan)位(wei)為(wei)(wei)伏特，其(qi)(qi)(qi)值為(wei)(wei)：交(jiao)(jiao)流電(dian)(dian)(dian)源的(de)(de)總電(dian)(dian)(dian)壓(ya)220V-蓄(xu)電(dian)(dian)(dian)池放(fang)電(dian)(dian)(dian)的(de)(de)下限電(dian)(dian)(dian)壓(ya)10V=210V；C表示電(dian)(dian)(dian)容器(qi)的(de)(de)容量，其(qi)(qi)(qi)單(dan)(dan)(dan)位(wei)為(wei)(wei)法拉：f表示交(jiao)(jiao)流電(dian)(dian)(dian)的(de)(de)頻(pin)率，其(qi)(qi)(qi)單(dan)(dan)(dan)位(wei)為(wei)(wei)赫茲，我國公(gong)共電(dian)(dian)(dian)網的(de)(de)頻(pin)率為(wei)(wei)50赫茲；I表示通過電(dian)(dian)(dian)容器(qi)的(de)(de)電(dian)(dian)(dian)流，其(qi)(qi)(qi)單(dan)(dan)(dan)位(wei)為(wei)(wei)安培；π取3．14)。

　　由以上(shang)計算結果可(ke)(ke)知(zhi)，當電(dian)(dian)(dian)(dian)容器(qi)(qi)(qi)C取(qu)(qu)15微(wei)(wei)法(即(ji)0．000015法拉)時，I=65940C=65940×0．000015≈1(A)。C1=15微(wei)(wei)法、C2=30微(wei)(wei)法、C3=60微(wei)(wei)法、C4=120微(wei)(wei)法，對(dui)應(ying)的(de)(de)(de)各支路電(dian)(dian)(dian)(dian)流分別為(wei)1A、2A、4A、8A。通(tong)過各控(kong)制(zhi)開關將以上(shang)四個電(dian)(dian)(dian)(dian)容器(qi)(qi)(qi)進行適當的(de)(de)(de)并(bing)聯(lian)組(zu)合(he)便(bian)可(ke)(ke)得到(dao)1A、2A、3A……15A的(de)(de)(de)15組(zu)可(ke)(ke)調充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流。如果想將電(dian)(dian)(dian)(dian)流調得更精(jing)細些，可(ke)(ke)增加并(bing)聯(lian)支路。如增加7．5微(wei)(wei)法支路可(ke)(ke)得到(dao)相鄰級(ji)(ji)差(cha)為(wei)0．5A的(de)(de)(de)0．5A～15．5A的(de)(de)(de)31級(ji)(ji)可(ke)(ke)調充(chong)電(dian)(dian)(dian)(dian)控(kong)制(zhi)系統，上(shang)述各支路電(dian)(dian)(dian)(dian)容器(qi)(qi)(qi)的(de)(de)(de)容量(liang)(liang)若只取(qu)(qu)其(qi)十(shi)分之(zhi)一(yi)，便(bian)可(ke)(ke)得到(dao)相鄰級(ji)(ji)差(cha)為(wei)O．1A的(de)(de)(de)0．1～1．5A的(de)(de)(de)15級(ji)(ji)可(ke)(ke)調并(bing)聯(lian)組(zu)合(he)充(chong)電(dian)(dian)(dian)(dian)控(kong)制(zhi)系統；若只取(qu)(qu)其(qi)容量(liang)(liang)的(de)(de)(de)百分之(zhi)一(yi)，便(bian)可(ke)(ke)得到(dao)相鄰級(ji)(ji)差(cha)為(wei)140mA的(de)(de)(de)15級(ji)(ji)可(ke)(ke)調并(bing)聯(lian)組(zu)合(he)充(chong)電(dian)(dian)(dian)(dian)控(kong)制(zhi)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(de)；電(dian)(dian)容器(qi)C1、C2、C3、C4均選用(yong)耐壓不(bu)小(xiao)于(yu)400V規(gui)格(ge)的(de)；泄放電(dian)(dian)阻(zu)R1、R2、R3、R4均選用(yong)220kΩ，1／2W規(gui)格(ge)的(de)；整流(liu)(liu)(liu)堆D應選用(yong)額定工作(zuo)電(dian)(dian)流(liu)(liu)(liu)不(bu)小(xiao)于(yu)50A，耐壓不(bu)小(xiao)于(yu)400V規(gui)格(ge)的(de)；電(dian)(dian)流(liu)(liu)(liu)表(biao)A選用(yong)量程(cheng)為(wei)20A或30A規(gui)格(ge)的(de)直(zhi)(zhi)流(liu)(liu)(liu)電(dian)(dian)流(liu)(liu)(liu)表(biao)；電(dian)(dian)壓表(biao)V應選用(yong)量程(cheng)為(wei)50V規(gui)格(ge)的(de)直(zhi)(zhi)流(liu)(liu)(liu)電(dian)(dian)壓表(biao)；R5選用(yong)10kΩ／6W的(de)電(dian)(dian)阻(zu)；LED選用(yong)普(pu)通(tong)小(xiao)功率發光二極管；K5選用(yong)普(pu)通(tong)按鍵式開關，工作(zuo)電(dian)(dian)流(liu)(liu)(liu)大小(xiao)不(bu)作(zuo)要求(qiu)。將控制(zhi)開關K1、K2、K3、K4并(bing)排裝在機殼面板上適當(dang)的(de)位置，并(bing)在K1、K2、K3、K4的(de)位置旁(pang)邊分別標注上1A、2A、4A、8A的(de)字(zi)樣，以(yi)便控制(zhi)計算調(diao)整。蓄電(dian)(dian)池接線柱的(de)工作(zuo)電(dian)(dian)流(liu)(liu)(liu)不(bu)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(le)人身安全，充(chong)電(dian)(dian)(dian)(dian)(dian)時應(ying)嚴格照下列程序(xu)進行(xing)操作：　　1．檢(jian)查各個開(kai)關應(ying)處(chu)于斷開(kai)狀態，將(jiang)(jiang)蓄(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)的(de)正、負(fu)極(ji)與接(jie)線(xian)柱連(lian)接(jie)可靠(kao)，然后閉合(he)K5，電(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)指示(shi)出蓄(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)兩端(duan)的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)。　　2．將(jiang)(jiang)電(dian)(dian)(dian)(dian)(dian)源(yuan)插頭插入220V交(jiao)流電(dian)(dian)(dian)(dian)(dian)源(yuan)，接(jie)通K1，此時，觀察電(dian)(dian)(dian)(dian)(dian)源(yuan)指示(shi)燈亮(liang)，空(kong)載報警指示(shi)發光二極(ji)管不(bu)應(ying)亮(liang)。若發光二極(ji)管亮(liang)，說明蓄(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)正、負(fu)極(ji)與充(chong)電(dian)(dian)(dian)(dian)(dian)器接(jie)線(xian)柱之間接(jie)觸不(bu)良，應(ying)除掉接(jie)點之間的(de)臟物(wu)后再進行(xing)連(lian)接(jie)。　　3．根據蓄(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)對(dui)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流的(de)要求，選擇合(he)適的(de)控制開(kai)關接(jie)通并聯調整(zheng)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流，充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流數值為接(jie)通的(de)開(kai)關電(dian)(dian)(dian)(dian)(dian)流數之和。

　　該(gai)充電(dian)(dian)(dian)器的唯一(yi)缺陷是，不(bu)具備充滿(man)電(dian)(dian)(dian)后自動停充的功能(neng)。因各種蓄電(dian)(dian)(dian)池的電(dian)(dian)(dian)壓(ya)(ya)及容量(liang)都不(bu)一(yi)樣(yang)，讀(du)者(zhe)應根據不(bu)同蓄電(dian)(dian)(dian)池的要(yao)求決定充電(dian)(dian)(dian)的電(dian)(dian)(dian)流和充電(dian)(dian)(dian)時間(jian)，通過電(dian)(dian)(dian)壓(ya)(ya)表(biao)監視充電(dian)(dian)(dian)程度。