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(juan)電(dian)(dian)(dian)(dian)流(liu)(liu)浮充充電(dian)(dian)(dian)(dian)階(jie)段(duan)時(shi)，充電(dian)(dian)(dian)(dian)器紅色(se)(se)二極(ji)管LED1兩端(duan)變為零電(dian)(dian)(dian)(dian)壓熄滅(充電(dian)(dian)(dian)(dian)器綠色(se)(se)二極(ji)管則發光(guang))，此時(shi)VT3也因基(ji)極(ji)零電(dian)(dian)(dian)(dian)壓而截止(zhi)，電(dian)(dian)(dian)(dian)源(yuan)(yuan)調(diao)整(zheng)管VT4正常導(dao)通(tong)，輸(shu)出(chu)(chu)2.1V直流(liu)(liu)電(dian)(dian)(dian)(dian)源(yuan)(yuan)，石英(ying)小(xiao)(xiao)鬧鐘得電(dian)(dian)(dian)(dian)開(kai)(kai)始(shi)計(ji)時(shi)，當計(ji)時(shi)到預先設定值(zhi)時(shi)，石英(ying)小(xiao)(xiao)鬧鐘輸(shu)出(chu)(chu)低電(dian)(dian)(dian)(dian)平(ping)音頻脈沖(chong)訊響信號(hao)，該低電(dian)(dian)(dian)(dian)平(ping)音頻脈沖(chong)信號(hao)通(tong)過(guo)VT2放大整(zheng)流(liu)(liu)經電(dian)(dian)(dian)(dian)容(rong)C5濾波輸(shu)出(chu)(chu)一直流(liu)(liu)電(dian)(dian)(dian)(dian)壓，使(shi)VT1飽和(he)導(dao)通(tong)，開(kai)(kai)關S1電(dian)(dian)(dian)(dian)磁脫鉤線圈(quan)得電(dian)(dian)(dian)(dian)產生(sheng)磁力，使(shi)開(kai)(kai)關按鈕脫鉤跳開(kai)(kai)，斷開(kai)(kai)交流(liu)(liu)電(dian)(dian)(dian)(dian)源(yuan)(yuan)，從而實現自動(dong)結(jie)束充電(dian)(dian)(dian)(dian)。

   智(zhi)能定(ding)時(shi)(shi)(shi)插(cha)座的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)見圖，共由(you)交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)開(kai)關(guan)、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁脫(tuo)鉤(gou)(gou)線圈(quan)(quan)驅動電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)、定(ding)時(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)、直(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)4部(bu)分組成。將(jiang)該電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)插(cha)上電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)插(cha)頭，按(an)下交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)開(kai)關(guan)S1按(an)鈕，接通220V交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)即(ji)可開(kai)始工作。220V交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)一路(lu)(lu)(lu)(lu)經14V電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)變壓(ya)(ya)器T降(jiang)壓(ya)(ya)、橋式整(zheng)(zheng)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)整(zheng)(zheng)流(liu)(liu)、濾(lv)波電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容C1濾(lv)波、三端穩壓(ya)(ya)集(ji)成電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)IC1穩壓(ya)(ya)、濾(lv)波電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容C2濾(lv)波產(chan)生穩定(ding)的+12V直(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)，該+12V分三路(lu)(lu)(lu)(lu)輸出：(1)經R4加(jia)(jia)(jia)到LED2作+12V直(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)工作指示。(2)經R3、VD2、LED3串聯(lian)穩壓(ya)(ya)后(hou)經C3濾(lv)波加(jia)(jia)(jia)到穩壓(ya)(ya)調整(zheng)(zheng)管VT4基極，使VT4將(jiang)+12V穩壓(ya)(ya)為2.1V，由(you)VT4發(fa)射極輸出，該2.1V經C4濾(lv)波后(hou)加(jia)(jia)(jia)到石英小鬧(nao)(nao)鐘電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)正負(fu)極為其提(ti)供直(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(提(ti)示一點：2.1V高(gao)了些(xie)，石英小鬧(nao)(nao)鐘走時(shi)(shi)(shi)稍(shao)快一些(xie)，定(ding)時(shi)(shi)(shi)值(zhi)按(an)4~5小時(shi)(shi)(shi)即(ji)可)。(3)加(jia)(jia)(jia)到開(kai)關(guan)S1的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁脫(tuo)鉤(gou)(gou)線圈(quan)(quan)上。

　　元件選擇
　　元件選(xuan)(xuan)擇如電(dian)路原理圖上的(de)標注：VT1、VT3、VT4選(xuan)(xuan)用(yong)(yong)(yong)S8050型三(san)極(ji)(ji)管，VT2選(xuan)(xuan)用(yong)(yong)(yong)S8550型三(san)極(ji)(ji)管，IC1選(xuan)(xuan)用(yong)(yong)(yong)LM7812，VD1選(xuan)(xuan)用(yong)(yong)(yong)IN4148型二(er)極(ji)(ji)管，VD2～D6選(xuan)(xuan)用(yong)(yong)(yong)IN4007型二(er)極(ji)(ji)管，LED1、LED2選(xuan)(xuan)用(yong)(yong)(yong)普(pu)(pu)通(tong)(tong)紅色發(fa)光(guang)二(er)極(ji)(ji)管，LED3選(xuan)(xuan)用(yong)(yong)(yong)普(pu)(pu)通(tong)(tong)綠色發(fa)光(guang)二(er)極(ji)(ji)管，R1選(xuan)(xuan)用(yong)(yong)(yong)2kΩ普(pu)(pu)通(tong)(tong)電(dian)阻(zu)，R2選(xuan)(xuan)用(yong)(yong)(yong)10kΩ普(pu)(pu)通(tong)(tong)電(dian)阻(zu)，R3、R4選(xuan)(xuan)用(yong)(yong)(yong)1kΩ普(pu)(pu)通(tong)(tong)電(dian)阻(zu)，開(kai)關S1選(xuan)(xuan)用(yong)(yong)(yong)KDC-A01-06Y型的(de)，P1和J1分別選(xuan)(xuan)用(yong)(yong)(yong)普(pu)(pu)通(tong)(tong)單(dan)聲道耳機插頭、插孔。變(bian)壓(ya)器T選(xuan)(xuan)用(yong)(yong)(yong)3W/14V電(dian)源變(bian)壓(ya)器，C1選(xuan)(xuan)用(yong)(yong)(yong)1000μF/25V電(dian)解(jie)電(dian)容(rong)，C2、C3、C4選(xuan)(xuan)470μF/25V電(dian)解(jie)電(dian)容(rong)，C5選(xuan)(xuan)用(yong)(yong)(yong)47μF/25V電(dian)解(jie)電(dian)容(rong)。