聲控開關(guan)是一(yi)種采用聲音激發拾音器進行聲電轉換來控制開關(guan)的(de)(de)閉合，并(bing)經(jing)(jing)過(guo)延時后能(neng)自動斷(duan)開的(de)(de)電子(zi)開關(guan)。經(jing)(jing)常使用在樓梯(ti)間等環境。

聲(sheng)控開關(guan)內(nei)部(bu)有(you)光敏電(dian)(dian)(dian)阻、碳晶咪頭、晶閘管(guan)、三極管(guan)、電(dian)(dian)(dian)容器等電(dian)(dian)(dian)子(zi)元件。聲(sheng)控開關(guan)一(yi)(yi)般都(dou)是(shi)串接在白熾燈(deng)泡(pao)電(dian)(dian)(dian)路(lu)中的(de)。220V交流(liu)(liu)市電(dian)(dian)(dian)經過(guo)燈(deng)泡(pao)送(song)達聲(sheng)控開關(guan)。開關(guan)內(nei)部(bu)有(you)一(yi)(yi)個整流(liu)(liu)橋。可以將交流(liu)(liu)電(dian)(dian)(dian)整流(liu)(liu)成直流(liu)(liu)電(dian)(dian)(dian)。因為電(dian)(dian)(dian)子(zi)元件都(dou)是(shi)使用(yong)直流(liu)(liu)電(dian)(dian)(dian)的(de)。

白天的(de)時候(hou)，光敏(min)電阻(zu)的(de)阻(zu)值較(jiao)小。就會屏蔽掉咪(mi)頭的(de)信號輸入。這樣即使有很大的(de)聲音。但是因為(wei)光敏(min)電阻(zu)的(de)下拉導致信號無法繼續(xu)傳送(song)，所以(yi)白天的(de)時候(hou)不(bu)亮。

夜晚(wan)的(de)(de)時候(hou)，光(guang)敏電(dian)(dian)(dian)(dian)(dian)阻阻值(zhi)變大(da)。此(ci)時如果(guo)有較大(da)的(de)(de)聲(sheng)音的(de)(de)話(hua)。聲(sheng)音會(hui)通過咪(mi)頭轉(zhuan)化為(wei)電(dian)(dian)(dian)(dian)(dian)信(xin)(xin)號。然后后級的(de)(de)放(fang)大(da)電(dian)(dian)(dian)(dian)(dian)路(lu)將此(ci)小(xiao)信(xin)(xin)號放(fang)大(da)。最后推(tui)動晶(jing)閘(zha)管導通，此(ci)時燈泡就會(hui)點(dian)亮。在晶(jing)閘(zha)管驅(qu)動電(dian)(dian)(dian)(dian)(dian)路(lu)中有一個阻容放(fang)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)路(lu)。這個電(dian)(dian)(dian)(dian)(dian)路(lu)就是延時電(dian)(dian)(dian)(dian)(dian)路(lu)。電(dian)(dian)(dian)(dian)(dian)容值(zhi)的(de)(de)大(da)小(xiao)和電(dian)(dian)(dian)(dian)(dian)阻值(zhi)的(de)(de)大(da)小(xiao)都(dou)會(hui)影響到延時量的(de)(de)變化。當電(dian)(dian)(dian)(dian)(dian)容器中的(de)(de)電(dian)(dian)(dian)(dian)(dian)荷放(fang)盡的(de)(de)時候(hou)，晶(jing)閘(zha)管就會(hui)在交流過零后自動關閉，此(ci)時燈泡就會(hui)熄滅(mie)了。