應急燈的工作原理詳解

應急燈的工作(zuo)原理分(fen)為在(zai)供電正常時情(qing)況下，停電情(qing)況下，制作(zuo)情(qing)況下。

應急燈(deng)又稱方便燈(deng),它不但可(ke)以在停電時作照明用(yong)(yong),也可(ke)以在無(wu)文流供電電潭的情況下實現(xian)照明等(deng)作用(yong)(yong)。

在供電(dian)(dian)(dian)(dian)(dian)(dian)正(zheng)常時，J2得電(dian)(dian)(dian)(dian)(dian)(dian)吸合，其動觸點(dian)與“N/O（常開點(dian)）”接通，后備(bei)蓄電(dian)(dian)(dian)(dian)(dian)(dian)池正(zheng)端與IC1的(de)(de)(de)反相端相聯。IC1（LM308）和(he)(he)D5、D6組成電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)比(bi)較 器(qi)，參考(kao)(kao)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)由D5、D6決(jue)定(ding)。這(zhe)里(li)用(yong)一個硅二極管(guan)（D5）和(he)(he)一個6.2V的(de)(de)(de)穩壓(ya)(ya)(ya)(ya)二極管(guan)（D6）組成6.9V的(de)(de)(de)參考(kao)(kao)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)，對充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)進(jin)行監控。當IC1 的(de)(de)(de)2腳(jiao)輸(shu)(shu)入(ru)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)（既蓄電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)）低(di)于(yu)6.9V時，IC1的(de)(de)(de)6腳(jiao)輸(shu)(shu)出(chu)高電(dian)(dian)(dian)(dian)(dian)(dian)平，T1導通，J1得電(dian)(dian)(dian)(dian)(dian)(dian)，其動觸點(dian)與“N/O（常開點(dian)）”接通，電(dian)(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)通過R2對 蓄電(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，同時LED2點(dian)亮(liang)為充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)指示(shi)。改變R2阻值可調整充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流。隨(sui)著充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)時間(jian)增加(jia)，IC1的(de)(de)(de)2腳(jiao)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)逐漸增加(jia)，當電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)大于(yu)參考(kao)(kao)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)6.9V 時，IC1的(de)(de)(de)6腳(jiao)輸(shu)(shu)出(chu)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)平，T1截(jie)止(zhi)，J1失電(dian)(dian)(dian)(dian)(dian)(dian)，斷開充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)回路，實現(xian)自動充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)保護功能。

當停電(dian)(dian)(dian)時(shi)，J2失去電(dian)(dian)(dian)源，其動觸點與“N/C（常閉點）”接通(tong)，蓄電(dian)(dian)(dian)池通(tong)過S1對應(ying)急(ji)燈電(dian)(dian)(dian)路(lu)供電(dian)(dian)(dian)，實(shi)現(xian)停電(dian)(dian)(dian)時(shi)自動切(qie)換功能。S1在這里用(yong)來(lai)手(shou)動切(qie)斷(duan)應(ying)急(ji)燈電(dian)(dian)(dian)路(lu)部分(fen)。

制作時，X1選用次級為6V/200mA的電源變壓器。J1、J2選用線圈電壓為6V的繼電器。其他器件選擇可參考圖示，無特殊要求。電路調試很簡單，接 通主電源電時，J2應該動作，LED1為電源指示。然后測量IC1的3腳電壓是否為6.9V左右，之后可用一個外接電源接入IC2腳來調整充電保護電路。 當輸入電壓大于6.9V時，J1應該動作斷開。短開S1，用外接電源接入應急燈電路，測量IC2的輸出是否50Hz，然后可測量X2輸出部分電壓是否為 220V左右既可。LED3為停電/應急燈工作。