MP-7 type carbon monoxide detection planar semiconductor gas sensor adopts advanced planar thick film production process. It is composed of heater and metal oxide semiconductor material formed on micro Al2O3 ceramic substrate. inside the cap. The high and low temperature cycle detection method is used to detect carbon monoxide (1.5V), and the impurity gas adsorbed at low temperature is cleaned at high temperature (5.0V). The conductivity of the sensor increases as the concentration of carbon monoxide gas in the air increases, and a simple circuit can convert the change in conductivity into an output signal corresponding to the gas concentration.