目前(qian)市(shi)場上出(chu)售(shou)的(de)(de)各種型(xing)號的(de)(de)充(chong)電器要求外接(jie)電源時正、負極(ji)性(xing)(xing)絕對不(bu)(bu)能(neng)有誤(wu)，否則充(chong)電時將燒壞電池(chi)或電器，這里介紹一種安全型(xing)充(chong)電器電路(lu)(lu)，使用時可不(bu)(bu)用校正正負極(ji)性(xing)(xing)，直接(jie)接(jie)入電池(chi)的(de)(de)極(ji)性(xing)(xing)，即(ji)能(neng)安全充(chong)電，使用起來很(hen)得心順手(shou)。該無極(ji)性(xing)(xing)充(chong)電器電路(lu)(lu)見附圖所(suo)示。

　　該電(dian)路(lu)由(you)二(er)只雙向(xiang)可(ke)控硅(gui)“VT1、VT2’、兩只整流二(er)極管“VD1、VD2’以及(ji)雙向(xiang)可(ke)控硅(gui)柵極觸發電(dian)路(lu)“R1、VD3、R2、VD4”等(deng)組成。

　　若電(dian)路不連接蓄電(dian)池，兩只可控硅“VT1、VT2’均無柵電(dian)流，不導通，因此即(ji)使有交(jiao)流輸(shu)入也沒(mei)有輸(shu)出電(dian)壓。確(que)保安全。

　　當電(dian)(dian)(dian)(dian)路中輸(shu)出(+)端(duan)連接電(dian)(dian)(dian)(dian)池(chi)正(zheng)極(ji)(ji)(ji)(ji)、輸(shu)出(-)端(duan)接負(fu)(fu)極(ji)(ji)(ji)(ji)時，由于蓄(xu)電(dian)(dian)(dian)(dian)池(chi)存在剩余電(dian)(dian)(dian)(dian)壓，將使(shi)VT1出柵極(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)流(liu)“經VT1、G極(ji)(ji)(ji)(ji)-VD3-R1”使(shi)VT1導(dao)通。在交(jiao)流(liu)電(dian)(dian)(dian)(dian)正(zheng)半周經VT1和(he)VT2對蓄(xu)電(dian)(dian)(dian)(dian)池(chi)進(jin)行充(chong)電(dian)(dian)(dian)(dian)：相反，若蓄(xu)電(dian)(dian)(dian)(dian)池(chi)正(zheng)極(ji)(ji)(ji)(ji)連(-)端(duan)、負(fu)(fu)極(ji)(ji)(ji)(ji)連(+)端(duan)，則VT2有柵極(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)流(liu)而導(dao)通，通過VT2和(he)VT1給(gei)蓄(xu)電(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)。

　　綜上(shang)所(suo)述：不(bu)論是電(dian)(dian)池正(zheng)極、負極輸出，(+、-)、(-、+)端連接均能(neng)正(zheng)常(chang)充(chong)電(dian)(dian)。如果蓄(xu)(xu)電(dian)(dian)池剩(sheng)余電(dian)(dian)壓(ya)(ya)(ya)過小不(bu)能(neng)觸發VT1或VT2導通，就不(bu)能(neng)進(jin)行充(chong)電(dian)(dian)。對于(yu)(yu)這(zhe)種情況，可用(yong)晶(jing)體管(guan)代替VD3和(he)VD4來減小晶(jing)閘管(guan)的觸發電(dian)(dian)壓(ya)(ya)(ya)。而(er)對于(yu)(yu)VT1、VT2和(he)VD1、VD2器(qi)(qi)件的要求(qiu)耐(nai)壓(ya)(ya)(ya)大于(yu)(yu)100V、連續工(gong)作電(dian)(dian)流為20A以上(shang)。VD3、VD4只需(xu)耐(nai)壓(ya)(ya)(ya)大于(yu)(yu)50V、工(gong)作電(dian)(dian)流100mA左右就行了。具體情況根據蓄(xu)(xu)電(dian)(dian)池的電(dian)(dian)壓(ya)(ya)(ya)及充(chong)電(dian)(dian)電(dian)(dian)流實(shi)際需(xu)要而(er)確定(ding)，靈活掌握(wo)選(xuan)用(yong)這(zhe)些(xie)電(dian)(dian)子元(yuan)器(qi)(qi)件。

　　例(li)如：要對48V蓄電池充電，限(xian)流電阻R1、R2功(gong)率需要2W以上(shang)的(de)電阻。但注(zhu)意,T電源(yuan)變壓器(qi)次級(ji)有直流成分電流通過，磁化電流增大，因此變壓器(qi)的(de)設計(ji)容量要大些，次級(ji)輸(shu)出電壓分別為7V、14V、28V、42V、56V，S選(xuan)用(yong)五(wu)擋轉換開(kai)關。其他元器(qi)件無特殊要求，按圖中所標的(de)參數為準。而輸(shu)出的(de)正負極(ji)分別為：6V、12V、24V、36V、48V。