The MH-Z19C carbon dioxide gas sensor is a general-purpose, intelligent, small sensor that uses the non-dispersive infrared (NDIR) principle to detect CO₂ in the air. It features excellent selectivity, oxygen independence, and long lifespan; built-in temperature compensation; and serial output, analog output, and PWM output for ease of use. This sensor is a high-performance device created by tightly integrating mature infrared absorption gas detection technology with precise optical path design and sophisticated circuit design.