Composition of passive infrared detectors

Passive infrared detectors mainly detect and receive infrared radiation from the outside world. The detector itself does not emit any energy, but is only sensitive to the infrared band emitted by the human body. The wavelength of infrared light radiated by the human body is 3-50 μm, of which 8-14 μm accounts for 46%, and the peak wavelength is 9.5 μm, so passive infrared detectors mainly receive infrared radiation with a wavelength of 8-14 μm.

Passive infrared detectors are mainly composed of optical system, pyroelectric infrared sensor, operational amplifier, signal processor, alarm control output and so on. The core component is a pyroelectric sensor, which can detect the change of thermal radiation in a three-dimensional defense space through the cooperation of the optical system.