應急燈的工作原理詳解

應急燈的(de)工作原理分為在供電正常時情況下，停電情況下，制作情況下。

應(ying)急燈又稱方便燈,它(ta)不但(dan)可以在(zai)停電(dian)時作照明用(yong),也可以在(zai)無文流供電(dian)電(dian)潭的(de)情況(kuang)下實(shi)現照明等作用(yong)。

在(zai)供電(dian)(dian)(dian)正常(chang)時，J2得(de)電(dian)(dian)(dian)吸合，其動觸(chu)點(dian)(dian)與(yu)“N/O（常(chang)開(kai)點(dian)(dian)）”接(jie)通，后(hou)備蓄(xu)電(dian)(dian)(dian)池正端與(yu)IC1的(de)反相端相聯。IC1（LM308）和D5、D6組成電(dian)(dian)(dian)壓(ya)比較 器，參考電(dian)(dian)(dian)壓(ya)由D5、D6決定。這里用一個硅二(er)極管（D5）和一個6.2V的(de)穩(wen)壓(ya)二(er)極管（D6）組成6.9V的(de)參考電(dian)(dian)(dian)壓(ya)，對充(chong)(chong)(chong)電(dian)(dian)(dian)壓(ya)電(dian)(dian)(dian)壓(ya)進(jin)行監控。當IC1 的(de)2腳(jiao)(jiao)輸(shu)(shu)入(ru)電(dian)(dian)(dian)壓(ya)（既蓄(xu)電(dian)(dian)(dian)池電(dian)(dian)(dian)壓(ya)）低(di)于6.9V時，IC1的(de)6腳(jiao)(jiao)輸(shu)(shu)出高電(dian)(dian)(dian)平，T1導通，J1得(de)電(dian)(dian)(dian)，其動觸(chu)點(dian)(dian)與(yu)“N/O（常(chang)開(kai)點(dian)(dian)）”接(jie)通，電(dian)(dian)(dian)源電(dian)(dian)(dian)壓(ya)通過R2對 蓄(xu)電(dian)(dian)(dian)池充(chong)(chong)(chong)電(dian)(dian)(dian)，同(tong)時LED2點(dian)(dian)亮為充(chong)(chong)(chong)電(dian)(dian)(dian)指示。改變R2阻值可(ke)調整充(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流。隨(sui)著(zhu)充(chong)(chong)(chong)電(dian)(dian)(dian)時間增加，IC1的(de)2腳(jiao)(jiao)電(dian)(dian)(dian)壓(ya)逐漸增加，當電(dian)(dian)(dian)壓(ya)大(da)于參考電(dian)(dian)(dian)壓(ya)6.9V 時，IC1的(de)6腳(jiao)(jiao)輸(shu)(shu)出低(di)電(dian)(dian)(dian)平，T1截止，J1失電(dian)(dian)(dian)，斷開(kai)充(chong)(chong)(chong)電(dian)(dian)(dian)回路，實現自動充(chong)(chong)(chong)電(dian)(dian)(dian)保護功能。

當(dang)停電(dian)(dian)(dian)時(shi)，J2失去電(dian)(dian)(dian)源，其(qi)動觸點(dian)與“N/C（常閉點(dian)）”接通(tong)，蓄電(dian)(dian)(dian)池(chi)通(tong)過(guo)S1對應(ying)急燈電(dian)(dian)(dian)路供電(dian)(dian)(dian)，實現停電(dian)(dian)(dian)時(shi)自(zi)動切(qie)換功能。S1在這(zhe)里(li)用來手動切(qie)斷應(ying)急燈電(dian)(dian)(dian)路部分(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。