2835燈珠是中(zhong)功(gong)率貼片超亮發光二極管,有0.1W和0.2W.

因其尺寸為2.8 (長(chang)) ×3.5 (寬) ×0.8 (厚) mm，固按照帖片LED燈珠尺寸命名方法，

命名(ming)為(wei)2835燈珠。功率：0.1W,電壓：2.8-3.6V之間，電流30mA/60mA .

如果燈珠是并聯的(de)話，電壓是相等的(de)，

也就(jiu)是燈珠的額(e)定電(dian)壓，電(dian)流(liu)也不大。按60mA計算(suan)的話(hua)，18顆的電(dian)流(liu)在1A 左(zuo)右。

在日常生活中，我們經常可以看(kan)到在小型家電(dian)(dian)的電(dian)(dian)源電(dian)(dian)路里，有很多采用的是(shi)阻(zu)容降壓電(dian)(dian)源電(dian)(dian)路，特別是(shi)LED燈泡用的比較多，那么(me)降壓電(dian)(dian)容的大小是(shi)怎么(me)確定(ding)的，帶(dai)著這個話題(ti)，現在以5W燈為例進行討論，此燈泡使用8只2835燈珠(zhu)，工作電(dian)(dian)壓18-19伏(fu)，電(dian)(dian)流(liu)30毫安。電(dian)(dian)壓我們取中間(jian)值(zhi)18.5伏(fu)，8個燈珠(zhu)兩(liang)(liang)端電(dian)(dian)壓為148伏(fu)，當電(dian)(dian)流(liu)30毫安時，電(dian)(dian)阻(zu)3兩(liang)(liang)端壓降為1.5伏(fu)，也就是(shi)說電(dian)(dian)容2兩(liang)(liang)端的電(dian)(dian)壓為149.5伏(fu)。

次級(ji)電(dian)(dian)(dian)(dian)流(liu)30毫安確實后(hou)，就(jiu)要考慮(lv)到(dao)電(dian)(dian)(dian)(dian)源的(de)效率，一般(ban)取值范圍為0.7-0.9，取中間值0.8，那么就(jiu)有：初(chu)級(ji)電(dian)(dian)(dian)(dian)流(liu)*0.8=次級(ji)電(dian)(dian)(dian)(dian)流(liu)，也(ye)就(jiu)是說(shuo)：初(chu)級(ji)電(dian)(dian)(dian)(dian)流(liu)=次級(ji)電(dian)(dian)(dian)(dian)流(liu)/0.8=30/0.8= 37.5毫安。AC兩(liang)端的(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)=149.5/1.414=105.7伏，阻容(rong)(rong)(rong)降壓(ya)(ya)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)兩(liang)端電(dian)(dian)(dian)(dian)壓(ya)(ya)=輸入(ru)電(dian)(dian)(dian)(dian)壓(ya)(ya)-AC兩(liang)端電(dian)(dian)(dian)(dian)壓(ya)(ya)=242-105.7=136.3伏，那么降壓(ya)(ya)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)容(rong)(rong)(rong)抗=136.3/37.5=3634.67歐(ou)姆，此時降壓(ya)(ya)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)容(rong)(rong)(rong)量=1/2兀(wu)f*3634.67=876納(na)法。實際(ji)上取900納(na)法，也(ye)就(jiu)是0.9微法。其(qi)它電(dian)(dian)(dian)(dian)路的(de)計(ji)算方(fang)法與此類似，都以輸出電(dian)(dian)(dian)(dian)流(liu)為基礎，考慮(lv)電(dian)(dian)(dian)(dian)源效率進行計(ji)算。

LED燈泡內部(bu)電原理圖(5W)2835燈珠8個

各種(zhong)計(ji)算(suan)及結果

燈泡內部實(shi)物