In many cities, induction lighting has been installed in residential corridors. At night, when someone passes by, the lights automatically turn on, and when someone passes by, the lights automatically turn off. Do you know how it works? This is an infrared induction delay power-off device. When there is someone, the infrared ray emitted by the human body is detected by it, and a pulse signal is generated. After this signal is amplified and shaped, the trigger circuit is driven to light up and start timing, and the loop is disconnected when the timing is over. Its advantage is that it will not be misoperated when there is a sound similar to a voice-activated delay switch.