Automatic cigarette lighter circuit principle

Automatic cigarette lighter circuit principle

　　The circuit working principle of the device is shown in the figure below. Normally, the light of the infrared light-emitting tube VD1 directly shines on the infrared receiving tube VD2, causing the internal resistance of VD2 to decrease, which is equivalent to the connection between the ① and ② pins of LSE. At this time, the ④ pin of LSE outputs a high level, the transistor VT is cut off, the relay J is in a released state, and the heating wire is not energized. Once a cigarette is inserted, the light on VD2 disappears, which is equivalent to the disconnection between the ① and ② pins of LSE, and the ④ pin of LSE becomes a low level. At this time, the transistor VT is turned on, J is attracted, and the heating wire is energized to ignite the cigarette. After the cigarette is taken out, the heating wire is powered off and stops working.