該充電器設計具有電池極(ji)性自動識(shi)別(bie)電路(lu)，免去了(le)以往需要人工(gong)轉換(huan)極(ji)性的(de)操作，使(shi)用起來更(geng)加方便

一、電路原理

　　電(dian)(dian)(dian)(dian)(dian)路(lu)如(ru)附圖所示：Q1及外圍元(yuan)件構成(cheng)自激振蕩器．經變壓(ya)器B降(jiang)壓(ya)、D5整流(liu)后在(zai)C4上得(de)到9.4v的直流(liu)電(dian)(dian)(dian)(dian)(dian)壓(ya)。通過R6限流(liu)．Q10(TL431)穩壓(ya)后．在(zai)Q3發射(she)極(ji)(ji)(ji)輸出(chu)4.2v電(dian)(dian)(dian)(dian)(dian)壓(ya)供鋰電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)。其極(ji)(ji)(ji)性自動識(shi)別電(dian)(dian)(dian)(dian)(dian)路(lu)由Q5～Q8、R12～R15組成(cheng)。當A點接電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)正極(ji)(ji)(ji)，B點接負極(ji)(ji)(ji)時，Q8因為有R12提供正偏電(dian)(dian)(dian)(dian)(dian)壓(ya)而(er)導通，Q5由R14提供偏壓(ya)導通。充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)由Q5→A點→電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)E→B點→Q8的C極(ji)(ji)(ji)形(xing)成(cheng)充(chong)電(dian)(dian)(dian)(dian)(dian)回路(lu)。當A點接電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)負極(ji)(ji)(ji)，而(er)B接電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)正極(ji)(ji)(ji)時充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)則(ze)由Q7→B點→電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)E→A點→Q6的C極(ji)(ji)(ji)形(xing)成(cheng)充(chong)電(dian)(dian)(dian)(dian)(dian)回路(lu)．從而(er)完成(cheng)自動識(shi)別電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)極(ji)(ji)(ji)性的功能。

　　當有(you)充電(dian)電(dian)流流過R6時(shi)，Q4導(dao)通，LED1閃爍發光(LED1為自帶振(zhen)蕩器的三色發光二極管，能夠隨機變幻出多彩的閃光)。充電(dian)完成后Q4因(yin)為沒(mei)有(you)足夠的導(dao)通電(dian)壓(ya)而截止，LED1熄滅。LED2為電(dian)源指示燈。

 電路原理圖

 　二、常見(jian)故障排除(chu)

　　故障一：電(dian)源指示(shi)燈不亮。

　　檢修：測(ce)Q1管正(zheng)常,但b極無偏(pian)置(zhi)電壓(ya)；再測(ce)R2為(wei)開路,更換R2后(hou)故障(zhang)排除(chu)。

　　故(gu)障二：電源指示燈不亮(liang)。檢修：測Q1已經擊穿,再(zai)測R1及R3均已開(kai)路(lu)。測其他元件(jian)正常(chang)，更換上述元件(jian)后(hou)故(gu)障排除(chu)。