This is MQ-9 Carbon Monoxide, Methane, and LPG Gas Sensor Module can be used to sense Carbon Monoxide and Methane Gas. Sensitive material of MQ-9 gas sensor is SnO2, which with lower conductivity in clean air. It makes detection by the method of cycle high and low temperature, and detect CO when the low temperature (heated by 1.5V). The sensor’s conductivity is higher along with the gas concentration rising. When high temperature (heated by 5.0V), it detects Methane, Propane etc. combustible gas and cleans the other gases adsorbed under low temperature. Wire Connections VCC – Positive pole (5V) GND – Negative pole DO – TTL switch signal output AO – Analog signal output Applications The domestic gas leakage detector Industrial gas detector Portable gas detector Features : Good sensitivity to CO/Combustible Gas High sensitivity to Methane, Propane, and CO Long life and low cost Simple drive circuit Package Includes : 1 x MQ-9 Carbon Monoxide, Methane, and LPG Gas Sensor Module SKU: PGI-0043970 Category: Gas Sensor