目(mu)前市場上(shang)出(chu)售(shou)的各種型號(hao)的充(chong)電(dian)(dian)(dian)器(qi)(qi)要(yao)求(qiu)外接(jie)電(dian)(dian)(dian)源時正、負極(ji)性(xing)絕對不能有誤(wu)，否(fou)則充(chong)電(dian)(dian)(dian)時將燒壞電(dian)(dian)(dian)池或電(dian)(dian)(dian)器(qi)(qi)，這里介紹一種安全型充(chong)電(dian)(dian)(dian)器(qi)(qi)電(dian)(dian)(dian)路，使(shi)用時可(ke)不用校(xiao)正正負極(ji)性(xing)，直接(jie)接(jie)入電(dian)(dian)(dian)池的極(ji)性(xing)，即能安全充(chong)電(dian)(dian)(dian)，使(shi)用起來很得心順手。該無極(ji)性(xing)充(chong)電(dian)(dian)(dian)器(qi)(qi)電(dian)(dian)(dian)路見附圖所示。

　　該電(dian)路由二只雙(shuang)向可控硅“VT1、VT2’、兩只整流二極管“VD1、VD2’以及雙(shuang)向可控硅柵(zha)極觸發電(dian)路“R1、VD3、R2、VD4”等組成。

　　若電路不(bu)(bu)連接(jie)蓄電池(chi)，兩只(zhi)可控硅“VT1、VT2’均無柵電流，不(bu)(bu)導通，因此(ci)即使有交(jiao)流輸(shu)入(ru)也沒有輸(shu)出電壓(ya)。確保安(an)全(quan)。

　　當電(dian)(dian)(dian)路中(zhong)輸(shu)出(chu)(+)端(duan)連(lian)接電(dian)(dian)(dian)池正極、輸(shu)出(chu)(-)端(duan)接負極時，由(you)于蓄電(dian)(dian)(dian)池存在剩(sheng)余電(dian)(dian)(dian)壓，將使(shi)VT1出(chu)柵極電(dian)(dian)(dian)流“經(jing)VT1、G極-VD3-R1”使(shi)VT1導通。在交流電(dian)(dian)(dian)正半周(zhou)經(jing)VT1和VT2對蓄電(dian)(dian)(dian)池進行充電(dian)(dian)(dian)：相反(fan)，若(ruo)蓄電(dian)(dian)(dian)池正極連(lian)(-)端(duan)、負極連(lian)(+)端(duan)，則VT2有柵極電(dian)(dian)(dian)流而導通，通過VT2和VT1給蓄電(dian)(dian)(dian)池充電(dian)(dian)(dian)。

　　綜上(shang)所述：不論(lun)是電(dian)池正(zheng)極(ji)、負(fu)極(ji)輸出，(+、-)、(-、+)端連接均能正(zheng)常(chang)充(chong)電(dian)。如果蓄電(dian)池剩(sheng)余電(dian)壓(ya)(ya)過小不能觸發VT1或VT2導通(tong)，就不能進行(xing)充(chong)電(dian)。對于(yu)(yu)這種(zhong)情(qing)況(kuang)，可用(yong)晶(jing)體管代替VD3和VD4來減小晶(jing)閘管的(de)觸發電(dian)壓(ya)(ya)。而對于(yu)(yu)VT1、VT2和VD1、VD2器件的(de)要求(qiu)耐壓(ya)(ya)大于(yu)(yu)100V、連續工(gong)作(zuo)電(dian)流(liu)(liu)為20A以上(shang)。VD3、VD4只需耐壓(ya)(ya)大于(yu)(yu)50V、工(gong)作(zuo)電(dian)流(liu)(liu)100mA左(zuo)右(you)就行(xing)了。具體情(qing)況(kuang)根(gen)據蓄電(dian)池的(de)電(dian)壓(ya)(ya)及充(chong)電(dian)電(dian)流(liu)(liu)實際需要而確(que)定(ding)，靈活掌(zhang)握(wo)選用(yong)這些電(dian)子元(yuan)器件。

　　例如：要(yao)對48V蓄(xu)電(dian)池充電(dian)，限流電(dian)阻(zu)R1、R2功率需要(yao)2W以上(shang)的電(dian)阻(zu)。但注意,T電(dian)源變壓器次(ci)(ci)級有直流成分(fen)(fen)電(dian)流通過，磁化電(dian)流增大，因(yin)此變壓器的設計容量要(yao)大些，次(ci)(ci)級輸出電(dian)壓分(fen)(fen)別為7V、14V、28V、42V、56V，S選用(yong)五擋轉換開關。其(qi)他元器件無特殊要(yao)求，按(an)圖中所(suo)標的參數(shu)為準。而輸出的正負極(ji)分(fen)(fen)別為：6V、12V、24V、36V、48V。