一、led手電筒工作原理

原子(zi)(zi)電子(zi)(zi)有很多(duo)能(neng)級，當電子(zi)(zi)從(cong)高能(neng)級向低(di)能(neng)級躍遷(qian)時，電子(zi)(zi)的能(neng)量(liang)就(jiu)減少了，而減少的能(neng)量(liang)則轉變成(cheng)光子(zi)(zi)發(fa)射出去。大量(liang)的這些光子(zi)(zi)就(jiu)是激光了。

LED發光原理類(lei)似。不(bu)過不(bu)同的(de)是，LED并不是(shi)通過(guo)原子(zi)內(nei)部的(de)電子(zi)躍變來發光的(de)，而是(shi)通過(guo)將(jiang)電壓加(jia)在LED的PN結(jie)兩端，使PN結本身形(xing)成一(yi)個能級(實際上，是一(yi)系列的能級)，然后電子(zi)在這個能(neng)級上躍變(bian)并產生光子(zi)來發光的。

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二、led手電筒電路圖

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強光手電筒電路圖

這(zhe)個電路大致可以(yi)分(fen)為(wei)三部分(fen)：1、整流降(jiang)壓部分(fen)；2、電池；3、發(fa)光回路部分(fen)

1、整流降壓(ya)部分由AC1、AC2、R1、C1、D1-D4、R及交(jiao)(jiao)(jiao)流指示燈組成(cheng)。220V交(jiao)(jiao)(jiao)流電(dian)源(yuan)接AC1、AC2。經R1、C1分壓(ya)后(hou)(hou)得到(dao)約6V的交(jiao)(jiao)(jiao)流電(dian)壓(ya)。經橋(qiao)式整流后(hou)(hou)在電(dian)池的負(fu)極和正極之間得到(dao)約4.2V的直(zhi)流電(dian)壓(ya)。

2、電池部分(fen)工作狀(zhuang)態有3種(zhong)：充電(dian)、放電(dian)、不充也不放。

（1）如果插(cha)上交流電(dian)(dian)(dian)，電(dian)(dian)(dian)池兩端(duan)接反(fan)極性電(dian)(dian)(dian)壓且大于電(dian)(dian)(dian)池放電(dian)(dian)(dian)電(dian)(dian)(dian)壓，電(dian)(dian)(dian)池就處于充(chong)電(dian)(dian)(dian)狀態(tai)（不管開關(guan)有沒有閉合(he)都充(chong)電(dian)(dian)(dian)）。

（2）不(bu)插交流電、閉合開(kai)關，發(fa)光回路(lu)接通，燈亮，電池放電。

（3）如果不插交流(liu)電(dian)(dian)(dian)，斷開(kai)開(kai)關，電(dian)(dian)(dian)池不充電(dian)(dian)(dian)也不放(fang)電(dian)(dian)(dian)。

3、發(fa)光(guang)回路由開關(guan)、白光(guang)發(fa)光(guang)二極管及其限流(liu)電(dian)(dian)阻與(yu)電(dian)(dian)池(chi)(chi)共(gong)同組成。只要開關(guan)閉合(he)燈就亮。插交(jiao)流(liu)電(dian)(dian)由交(jiao)流(liu)供電(dian)(dian)，否(fou)則由電(dian)(dian)池(chi)(chi)供電(dian)(dian)。

這(zhe)個簡(jian)單，C1是(shi)限流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)容，R1是(shi)C1的泄放(fang)電(dian)(dian)(dian)(dian)(dian)阻（防止(zhi)在(zai)(zai)拔(ba)掉插(cha)頭(tou)后(hou)，C1的殘存(cun)電(dian)(dian)(dian)(dian)(dian)壓通過插(cha)頭(tou)電(dian)(dian)(dian)(dian)(dian)人(ren)），D1～D4構成了橋(qiao)式整流(liu)(liu)(liu)(liu)，將C1限流(liu)(liu)(liu)(liu)后(hou)的交流(liu)(liu)(liu)(liu)變為了直流(liu)(liu)(liu)(liu)，然后(hou)送(song)給(gei)電(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)，因為電(dian)(dian)(dian)(dian)(dian)池(chi)的存(cun)在(zai)(zai)，所以限流(liu)(liu)(liu)(liu)后(hou)的電(dian)(dian)(dian)(dian)(dian)壓不會(hui)低于(yu)電(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)壓（相當(dang)于(yu)穩壓作用(yong)），考慮(lv)到(dao)二極管(guan)的降壓作用(yong)，因此才(cai)有了D1那端為6V電(dian)(dian)(dian)(dian)(dian)壓的緣故。

LED10及330歐電阻(zu)是充電指(zhi)示燈。至于燈后面的部(bu)分，就是5組LED加限流電阻(zu)構成的照(zhao)明電路，沒什(shen)么特別的。

其實，嚴(yan)格(ge)地(di)說那個電(dian)容(rong)不是(shi)降壓電(dian)容(rong)，而只是(shi)限流，降壓還需要配合后面的穩(wen)壓二極(ji)管等(deng)。但是(shi)，人(ren)們通常喜歡將這個電(dian)路(lu)叫“電(dian)容(rong)降壓”電(dian)路(lu)。

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如(ru)果AC2電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)高，電(dian)(dian)(dian)(dian)流(liu)經(jing)(jing)D4、電(dian)(dian)(dian)(dian)池、D2再到AC1。如(ru)果AC1電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)高，電(dian)(dian)(dian)(dian)流(liu)經(jing)(jing)D1、電(dian)(dian)(dian)(dian)池、D3再到AC2。因此，不(bu)管AC幾高，總是上邊的電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)高，都變成了(le)上正(zheng)下負，即(ji)實現了(le)整流(liu)。

如果沒D2，那么(me)當(dang)AC1電壓高的時候，會通(tong)過D3直接向(xiang)AC2短路。

強光手電什么牌子好>>