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　　如圖所(suo)(suo)示，該充電(dian)(dian)(dian)(dian)器(qi)(qi)屬于(yu)電(dian)(dian)(dian)(dian)容限流(liu)(liu)(liu)式無(wu)電(dian)(dian)(dian)(dian)源變壓(ya)器(qi)(qi)恒流(liu)(liu)(liu)充電(dian)(dian)(dian)(dian)器(qi)(qi)。220V交流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)經K1～K4及(ji)其(qi)相應阻容元件組成的(de)4條并列(lie)支路(lu)選擇(ze)或(huo)組合，再經整流(liu)(liu)(liu)堆D整流(liu)(liu)(liu)后，通(tong)過電(dian)(dian)(dian)(dian)流(liu)(liu)(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，由于(yu)回路(lu)中蓄電(dian)(dian)(dian)(dian)池兩端電(dian)(dian)(dian)(dian)的(de)變化量相對于(yu)220V交流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)壓(ya)來說很(hen)小(xiao)，電(dian)(dian)(dian)(dian)容兩端的(de)電(dian)(dian)(dian)(dian)壓(ya)降(jiang)幾乎可認(ren)為是(shi)不變的(de)，所(suo)(suo)以，通(tong)過電(dian)(dian)(dian)(dian)容器(qi)(qi)的(de)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)也是(shi)不變的(de)，通(tong)過蓄電(dian)(dian)(dian)(dian)池內部的(de)充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)自(zi)然也是(shi)恒定的(de)。 　　

     L為220V交流電(dian)(dian)(dian)(dian)(dian)源指(zhi)示(shi)(shi)燈，R1、R2、R3、R4分(fen)別(bie)是電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)(qi)(qi)C1、C2、C3、C4的(de)泄放(fang)電(dian)(dian)(dian)(dian)(dian)阻，在(zai)不用充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)時(shi)，能及時(shi)將電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)(qi)(qi)上積存(cun)的(de)電(dian)(dian)(dian)(dian)(dian)荷放(fang)掉；K1、K2、K3、K4是支路控制開關，通(tong)過開關通(tong)斷控制可以決定支路是否并入(ru)電(dian)(dian)(dian)(dian)(dian)路；R5、LED組成空(kong)載報(bao)警指(zhi)示(shi)(shi)電(dian)(dian)(dian)(dian)(dian)路(為了安全(quan)，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)不可在(zai)空(kong)載狀態下插入(ru)220V交流電(dian)(dian)(dian)(dian)(dian)源)，LED亮時(shi)，說明空(kong)載。電(dian)(dian)(dian)(dian)(dian)流表(biao)A指(zhi)示(shi)(shi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流的(de)大小：電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)表(biao)V指(zhi)示(shi)(shi)蓄電(dian)(dian)(dian)(dian)(dian)池兩(liang)端(duan)的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(為防止(zhi)空(kong)載時(shi)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)高燒壞(huai)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)表(biao)，電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)表(biao)的(de)接入(ru)與否受開關K5的(de)控制)。

　　二、電路設計　　該充電器的(de)(de)限流(liu)電(dian)(dian)(dian)容器容量越(yue)(yue)大，容抗越(yue)(yue)小(xiao)，充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)越(yue)(yue)大。反之，充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)越(yue)(yue)小(xiao)。根(gen)據該原理，可(ke)采用(yong)調(diao)(diao)整并聯(lian)電(dian)(dian)(dian)容的(de)(de)方法來達(da)到調(diao)(diao)整充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)大小(xiao)的(de)(de)目的(de)(de)。以汽(qi)車(che)(che)、摩托(tuo)車(che)(che)、電(dian)(dian)(dian)動自行車(che)(che)常用(yong)的(de)(de)蓄電(dian)(dian)(dian)池為例，該充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)路(lu)(lu)設(she)置了相鄰級(ji)(ji)差為1A的(de)(de)1～15A的(de)(de)15級(ji)(ji)可(ke)調(diao)(diao)充(chong)電(dian)(dian)(dian)，通過四(si)條支路(lu)(lu)的(de)(de)不同(tong)并聯(lian)組合實現(xian)對(dui)畜電(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)的(de)(de)調(diao)(diao)整。

　　由純電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)交流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)路中(zhong)(zhong)(圖中(zhong)(zhong)各分(fen)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)阻的(de)分(fen)流(liu)(liu)(liu)(liu)很小，可(ke)忽略不計)電(dian)(dian)(dian)(dian)壓、電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)、容(rong)(rong)(rong)(rong)抗之間的(de)關系得(de)：I=U／Xc=2πfcU=2×3．14×50×210C=65940C(式中(zhong)(zhong)，Xc表示(shi)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)的(de)容(rong)(rong)(rong)(rong)抗，其(qi)單位為(wei)歐姆；U表示(shi)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)兩(liang)端(duan)的(de)電(dian)(dian)(dian)(dian)壓，其(qi)單位為(wei)伏特，其(qi)值為(wei)：交流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)源的(de)總電(dian)(dian)(dian)(dian)壓220V-蓄(xu)電(dian)(dian)(dian)(dian)池放(fang)電(dian)(dian)(dian)(dian)的(de)下限(xian)電(dian)(dian)(dian)(dian)壓10V=210V；C表示(shi)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)的(de)容(rong)(rong)(rong)(rong)量，其(qi)單位為(wei)法拉：f表示(shi)交流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)的(de)頻(pin)率，其(qi)單位為(wei)赫(he)茲，我(wo)國公共電(dian)(dian)(dian)(dian)網的(de)頻(pin)率為(wei)50赫(he)茲；I表示(shi)通過電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)的(de)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)，其(qi)單位為(wei)安培(pei)；π取3．14)。

　　由以上(shang)計算結果(guo)可(ke)(ke)知，當電(dian)(dian)容(rong)器C取15微(wei)法(fa)(即(ji)0．000015法(fa)拉(la))時，I=65940C=65940×0．000015≈1(A)。C1=15微(wei)法(fa)、C2=30微(wei)法(fa)、C3=60微(wei)法(fa)、C4=120微(wei)法(fa)，對(dui)應的(de)(de)(de)各支(zhi)(zhi)路電(dian)(dian)流分別為(wei)1A、2A、4A、8A。通(tong)過各控制開關將(jiang)以上(shang)四個電(dian)(dian)容(rong)器進行適當的(de)(de)(de)并(bing)(bing)聯(lian)(lian)組(zu)合(he)便(bian)可(ke)(ke)得(de)(de)到1A、2A、3A……15A的(de)(de)(de)15組(zu)可(ke)(ke)調(diao)充電(dian)(dian)電(dian)(dian)流。如(ru)果(guo)想將(jiang)電(dian)(dian)流調(diao)得(de)(de)更精細些，可(ke)(ke)增加并(bing)(bing)聯(lian)(lian)支(zhi)(zhi)路。如(ru)增加7．5微(wei)法(fa)支(zhi)(zhi)路可(ke)(ke)得(de)(de)到相(xiang)(xiang)鄰(lin)級(ji)差為(wei)0．5A的(de)(de)(de)0．5A～15．5A的(de)(de)(de)31級(ji)可(ke)(ke)調(diao)充電(dian)(dian)控制系(xi)統，上(shang)述各支(zhi)(zhi)路電(dian)(dian)容(rong)器的(de)(de)(de)容(rong)量若只取其十分之一，便(bian)可(ke)(ke)得(de)(de)到相(xiang)(xiang)鄰(lin)級(ji)差為(wei)O．1A的(de)(de)(de)0．1～1．5A的(de)(de)(de)15級(ji)可(ke)(ke)調(diao)并(bing)(bing)聯(lian)(lian)組(zu)合(he)充電(dian)(dian)控制系(xi)統；若只取其容(rong)量的(de)(de)(de)百分之一，便(bian)可(ke)(ke)得(de)(de)到相(xiang)(xiang)鄰(lin)級(ji)差為(wei)140mA的(de)(de)(de)15級(ji)可(ke)(ke)調(diao)并(bing)(bing)聯(lian)(lian)組(zu)合(he)充電(dian)(dian)控制系(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)；電(dian)容器C1、C2、C3、C4均(jun)選用(yong)耐壓不(bu)(bu)小(xiao)(xiao)于400V規格的(de)；泄放電(dian)阻R1、R2、R3、R4均(jun)選用(yong)220kΩ，1／2W規格的(de)；整(zheng)流堆D應選用(yong)額定工作電(dian)流不(bu)(bu)小(xiao)(xiao)于50A，耐壓不(bu)(bu)小(xiao)(xiao)于400V規格的(de)；電(dian)流表(biao)(biao)A選用(yong)量程為20A或30A規格的(de)直流電(dian)流表(biao)(biao)；電(dian)壓表(biao)(biao)V應選用(yong)量程為50V規格的(de)直流電(dian)壓表(biao)(biao)；R5選用(yong)10kΩ／6W的(de)電(dian)阻；LED選用(yong)普通小(xiao)(xiao)功(gong)率發(fa)光二極管(guan)；K5選用(yong)普通按鍵式開(kai)關，工作電(dian)流大小(xiao)(xiao)不(bu)(bu)作要求。將控制開(kai)關K1、K2、K3、K4并(bing)排裝在機(ji)殼面(mian)板上適當的(de)位(wei)置(zhi)，并(bing)在K1、K2、K3、K4的(de)位(wei)置(zhi)旁邊分別(bie)標注(zhu)上1A、2A、4A、8A的(de)字樣，以便(bian)控制計(ji)算調(diao)整(zheng)。蓄電(dian)池接線柱的(de)工作電(dian)流不(bu)(bu)小(xiao)(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，為了人身安全，充(chong)電(dian)(dian)(dian)時應(ying)嚴格(ge)照下列程序(xu)進(jin)(jin)行操作：　　1．檢查各個(ge)開(kai)(kai)關應(ying)處于斷開(kai)(kai)狀態(tai)，將蓄(xu)(xu)電(dian)(dian)(dian)池的(de)(de)正、負(fu)(fu)極(ji)與(yu)接(jie)(jie)線柱連(lian)接(jie)(jie)可(ke)靠，然后(hou)閉合K5，電(dian)(dian)(dian)壓(ya)表指(zhi)(zhi)(zhi)示出蓄(xu)(xu)電(dian)(dian)(dian)池兩端的(de)(de)電(dian)(dian)(dian)壓(ya)。　　2．將電(dian)(dian)(dian)源(yuan)插頭(tou)插入(ru)220V交流電(dian)(dian)(dian)源(yuan)，接(jie)(jie)通K1，此時，觀察電(dian)(dian)(dian)源(yuan)指(zhi)(zhi)(zhi)示燈亮，空(kong)載報警指(zhi)(zhi)(zhi)示發光二極(ji)管(guan)不應(ying)亮。若(ruo)發光二極(ji)管(guan)亮，說明蓄(xu)(xu)電(dian)(dian)(dian)池正、負(fu)(fu)極(ji)與(yu)充(chong)電(dian)(dian)(dian)器接(jie)(jie)線柱之間(jian)接(jie)(jie)觸不良，應(ying)除掉(diao)接(jie)(jie)點(dian)之間(jian)的(de)(de)臟物后(hou)再進(jin)(jin)行連(lian)接(jie)(jie)。　　3．根據蓄(xu)(xu)電(dian)(dian)(dian)池對充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流的(de)(de)要求，選擇合適(shi)的(de)(de)控制(zhi)開(kai)(kai)關接(jie)(jie)通并聯調整充(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)開(kai)(kai)關電(dian)(dian)(dian)流數之和。

　　該充電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)的(de)唯一缺(que)陷是，不(bu)(bu)具備充滿電(dian)(dian)(dian)(dian)(dian)(dian)后自動(dong)停(ting)充的(de)功能。因(yin)各種(zhong)蓄電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓及容量都不(bu)(bu)一樣(yang)，讀者應根據不(bu)(bu)同蓄電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)要求決定(ding)充電(dian)(dian)(dian)(dian)(dian)(dian)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流和充電(dian)(dian)(dian)(dian)(dian)(dian)時間，通過電(dian)(dian)(dian)(dian)(dian)(dian)壓表監視充電(dian)(dian)(dian)(dian)(dian)(dian)程(cheng)度。