220V交流電源另一路經定時插座加到充電器，當充電器還未轉入浮充充電狀態時，充電器的紅燈LED1得電發光，LED1兩端的2V電壓經插頭P1、插孔J1、電阻R2加到VT3基極，VT3飽和導通，將2.1V穩壓調整管VT4基極短路到地，穩壓調整管VT4截止，石英小鬧鐘無直流電源供給而不工作，當充電器轉入涓電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)浮(fu)充(chong)(chong)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)階段時(shi)(shi)，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)紅色二極(ji)管LED1兩端變為零電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)熄滅(充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)綠色二極(ji)管則發光(guang))，此時(shi)(shi)VT3也因基極(ji)零電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)而(er)截(jie)止，電(dian)(dian)(dian)(dian)(dian)(dian)源調整(zheng)管VT4正(zheng)常導通(tong)，輸出2.1V直(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)源，石英(ying)(ying)小(xiao)(xiao)鬧(nao)鐘(zhong)得電(dian)(dian)(dian)(dian)(dian)(dian)開(kai)始(shi)計時(shi)(shi)，當計時(shi)(shi)到預先設定值(zhi)時(shi)(shi)，石英(ying)(ying)小(xiao)(xiao)鬧(nao)鐘(zhong)輸出低(di)電(dian)(dian)(dian)(dian)(dian)(dian)平音頻(pin)脈沖訊響信(xin)(xin)號(hao)，該(gai)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)平音頻(pin)脈沖信(xin)(xin)號(hao)通(tong)過VT2放大整(zheng)流(liu)經(jing)電(dian)(dian)(dian)(dian)(dian)(dian)容C5濾波(bo)輸出一直(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，使(shi)VT1飽和導通(tong)，開(kai)關(guan)S1電(dian)(dian)(dian)(dian)(dian)(dian)磁脫(tuo)鉤線圈得電(dian)(dian)(dian)(dian)(dian)(dian)產生磁力，使(shi)開(kai)關(guan)按鈕脫(tuo)鉤跳開(kai)，斷開(kai)交流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)源，從而(er)實(shi)現自動(dong)結束(shu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。

   智能定(ding)時插(cha)座(zuo)的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)見圖(tu)，共由交(jiao)(jiao)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)開關、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁脫鉤(gou)(gou)線圈驅動電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)、定(ding)時電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)、直(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)4部(bu)分(fen)組成。將該(gai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)插(cha)上(shang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)插(cha)頭，按(an)下交(jiao)(jiao)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)開關S1按(an)鈕，接通220V交(jiao)(jiao)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)即可開始工作。220V交(jiao)(jiao)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)一(yi)路(lu)(lu)經14V電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)變壓器T降壓、橋式整流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)整流(liu)、濾(lv)(lv)波電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)C1濾(lv)(lv)波、三端穩(wen)(wen)(wen)壓集成電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)IC1穩(wen)(wen)(wen)壓、濾(lv)(lv)波電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)C2濾(lv)(lv)波產生穩(wen)(wen)(wen)定(ding)的+12V直(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)，該(gai)+12V分(fen)三路(lu)(lu)輸(shu)出：(1)經R4加(jia)(jia)到(dao)(dao)LED2作+12V直(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)工作指(zhi)示(shi)。(2)經R3、VD2、LED3串聯穩(wen)(wen)(wen)壓后經C3濾(lv)(lv)波加(jia)(jia)到(dao)(dao)穩(wen)(wen)(wen)壓調整管VT4基極，使VT4將+12V穩(wen)(wen)(wen)壓為2.1V，由VT4發射極輸(shu)出，該(gai)2.1V經C4濾(lv)(lv)波后加(jia)(jia)到(dao)(dao)石英小(xiao)鬧鐘電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)正負(fu)極為其提供直(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(提示(shi)一(yi)點：2.1V高了(le)些(xie)，石英小(xiao)鬧鐘走時稍快(kuai)一(yi)些(xie)，定(ding)時值按(an)4~5小(xiao)時即可)。(3)加(jia)(jia)到(dao)(dao)開關S1的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁脫鉤(gou)(gou)線圈上(shang)。

　　元件選擇
　　元件選(xuan)擇如電(dian)(dian)路原理圖(tu)上(shang)的標(biao)注：VT1、VT3、VT4選(xuan)用(yong)(yong)(yong)S8050型(xing)(xing)三極(ji)(ji)管，VT2選(xuan)用(yong)(yong)(yong)S8550型(xing)(xing)三極(ji)(ji)管，IC1選(xuan)用(yong)(yong)(yong)LM7812，VD1選(xuan)用(yong)(yong)(yong)IN4148型(xing)(xing)二(er)極(ji)(ji)管，VD2～D6選(xuan)用(yong)(yong)(yong)IN4007型(xing)(xing)二(er)極(ji)(ji)管，LED1、LED2選(xuan)用(yong)(yong)(yong)普(pu)通(tong)(tong)(tong)紅色發光二(er)極(ji)(ji)管，LED3選(xuan)用(yong)(yong)(yong)普(pu)通(tong)(tong)(tong)綠色發光二(er)極(ji)(ji)管，R1選(xuan)用(yong)(yong)(yong)2kΩ普(pu)通(tong)(tong)(tong)電(dian)(dian)阻(zu)，R2選(xuan)用(yong)(yong)(yong)10kΩ普(pu)通(tong)(tong)(tong)電(dian)(dian)阻(zu)，R3、R4選(xuan)用(yong)(yong)(yong)1kΩ普(pu)通(tong)(tong)(tong)電(dian)(dian)阻(zu)，開關S1選(xuan)用(yong)(yong)(yong)KDC-A01-06Y型(xing)(xing)的，P1和J1分別選(xuan)用(yong)(yong)(yong)普(pu)通(tong)(tong)(tong)單聲(sheng)道耳機插頭、插孔。變壓器(qi)T選(xuan)用(yong)(yong)(yong)3W/14V電(dian)(dian)源變壓器(qi)，C1選(xuan)用(yong)(yong)(yong)1000μF/25V電(dian)(dian)解(jie)電(dian)(dian)容(rong)，C2、C3、C4選(xuan)470μF/25V電(dian)(dian)解(jie)電(dian)(dian)容(rong)，C5選(xuan)用(yong)(yong)(yong)47μF/25V電(dian)(dian)解(jie)電(dian)(dian)容(rong)。