Introduction Most pyroelectric sensors include an integrated JFET (Junction Field Effect Transistor) configured as a source follower. This buffer converts the extremely high impedance of the pyroelectric element to a more manageable level and provides initial amplification. Why a JFET…

Introduction Almost all PIR sensors use a dual-element design. This is not arbitrary – it’s essential for the sensor’s function. This article explains why two elements are better than one. The Problem with Single-Element Sensors A single pyroelectric element responds…

Introduction Pyroelectric sensors are widely used in flame detectors for industrial safety systems. Unlike motion detection, flame detection relies on sensing the characteristic flicker of flames and their spectral signature. Flame Characteristics Flames from hydrocarbon fires have two key properties…

Introduction Industrial environments place unique demands on PIR sensors. This guide helps you select the right sensor for factory automation, hazardous areas, and heavy-duty applications. Key Requirements for Industrial PIR Sensors 1. Extended Temperature Range Industrial environments may range from…

Introduction PIR sensors don’t respond instantly. Their response time is governed by two factors: the thermal time constant of the pyroelectric element and the electrical time constant of the readout circuit. This article explains these parameters and their practical implications.…

Introduction While commonly used for motion detection, pyroelectric sensors are also the heart of Non-Dispersive Infrared (NDIR) gas sensors. This article explains the principles and applications. NDIR Principle NDIR gas sensing works on the principle that many gases absorb infrared…

Introduction The optical window of a PIR sensor protects the pyroelectric element while allowing infrared radiation to pass. Two common materials are silicon and germanium. This article compares their properties. Silicon Windows Silicon (Si) is the most common window material…

Introduction Noise Equivalent Power (NEP) is a key figure of merit for infrared detectors. It quantifies the minimum detectable signal power. This article explains what NEP means for PIR sensors and how to use it in design. Definition of NEP…

Introduction Thermal camera arrays (e.g., MLX90640, AMG8833) are becoming popular for occupancy sensing. This article compares them with traditional PIR sensors to help you choose the right technology. How Thermal Camera Arrays Work Thermopile arrays consist of multiple thermopile sensors…

Introduction The final stage in a PIR signal chain is a comparator that converts the analog signal to a clean digital output. Adding hysteresis prevents oscillation when the signal hovers near the threshold. Why Hysteresis is Essential Without hysteresis, when…