該充電器設計具有電池極(ji)性自動識(shi)別電路，免(mian)去(qu)了以往需要人工轉換極(ji)性的操作(zuo)，使用起來更加方便

一、電路原理

　　電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)如附圖所示：Q1及外(wai)圍元件構成(cheng)自激振(zhen)蕩器．經變壓(ya)器B降壓(ya)、D5整流(liu)后在C4上得(de)到(dao)9.4v的直流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)。通(tong)過R6限(xian)流(liu)．Q10(TL431)穩壓(ya)后．在Q3發射極輸出(chu)4.2v電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)供鋰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。其極性(xing)自動識(shi)別電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)由(you)Q5～Q8、R12～R15組成(cheng)。當A點接電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)正極，B點接負極時，Q8因(yin)為有R12提(ti)供正偏(pian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)而導通(tong)，Q5由(you)R14提(ti)供偏(pian)壓(ya)導通(tong)。充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)由(you)Q5→A點→電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)E→B點→Q8的C極形(xing)成(cheng)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)回路(lu)。當A點接電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)負極，而B接電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)正極時充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)則(ze)由(you)Q7→B點→電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)E→A點→Q6的C極形(xing)成(cheng)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)回路(lu)．從(cong)而完成(cheng)自動識(shi)別電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)極性(xing)的功(gong)能。

　　當(dang)有充(chong)電(dian)電(dian)流流過R6時，Q4導通，LED1閃爍發(fa)光(LED1為(wei)自帶振蕩器(qi)的(de)(de)三色發(fa)光二極(ji)管，能夠隨機變幻出多彩的(de)(de)閃光)。充(chong)電(dian)完成后Q4因為(wei)沒有足夠的(de)(de)導通電(dian)壓而(er)截止，LED1熄滅。LED2為(wei)電(dian)源指示(shi)燈(deng)。

 電路原理圖

 　二、常(chang)見故障排除

　　故障(zhang)一：電源指示燈不亮。

　　檢修(xiu)：測Q1管正常,但b極無(wu)偏置電壓；再(zai)測R2為開路,更換R2后(hou)故障排除。

　　故(gu)障二：電源指示(shi)燈不亮。檢修：測Q1已經擊穿,再測R1及(ji)R3均(jun)已開路。測其(qi)他(ta)元(yuan)件(jian)正常(chang)，更換上述元(yuan)件(jian)后故(gu)障排除(chu)。