The gas sensing material used in the MQ136 hydrogen sulfide gas sensor is tin dioxide (SnO2), which has a low conductivity in clean air. When there is hydrogen sulfide gas in the environment where the sensor is located, the conductivity of the sensor increases with the increase of the hydrogen sulfide gas concentration in the air. The change in conductivity can be converted into an output signal corresponding to the gas concentration using a simple circuit.

The MEMS hydrogen sulfide gas sensor is composed of a Si-based micro-hot plate made of MEMS technology and a metal-oxide-semiconductor material with low conductivity in clean air. When the detected gas is present in the ambient air, the conductivity of the sensor changes. The higher the concentration of this gas, the higher the conductivity of the sensor. The change in conductivity can be converted into an output signal corresponding to the gas concentration using a simple circuit.

MP-4 combustible gas sensor (gas sensor, natural gas sensor) adopts multi-layer thick film manufacturing process. The heater and metal oxide semiconductor gas sensing layer are respectively made on both sides of the micro Al2O3 ceramic substrate, and are packaged in a metal shell. The conductivity of the sensor changes when the detected gas is present in the ambient air. The higher the concentration of this gas, the higher the conductivity of the sensor. This change in conductivity can be converted into an output signal corresponding to the gas concentration using a simple circuit.

MH-440D infrared sensor is a general-purpose intelligent infrared gas sensor (hereinafter referred to as the sensor). Dependence, stable performance, long life; built-in temperature compensation. The sensor is a compact and high-performance sensor that combines the mature infrared absorption gas detection technology with micro-machining and sophisticated circuit design. It is easy to use, can be directly used to replace catalytic combustion elements, and is widely used in various occasions where flammable and explosive gases exist.

The gas-sensing material used in the MQ-2 smoke sensor is tin dioxide (SnO2), which has a low conductivity in clean air. When there is flammable gas in the environment where the smoke sensor is located, the conductivity of the smoke sensor increases with the increase of the concentration of flammable gas in the air. The change in conductivity can be converted into an output signal corresponding to the gas concentration of this smoke sensor using a simple circuit.

The MQ-2 gas smoke sensor has high sensitivity to liquefied gas, propane, and hydrogen, and is also ideal for the detection of natural gas and other combustible vapors. This gas sensor can detect a variety of flammable gases and is a low-cost smoke sensor suitable for a variety of applications.

The MEMS smoke gas sensor is composed of a Si-based micro-hot plate based on MEMS technology and a metal oxide semiconductor gas sensing material with low conductivity in clean air. When the detected gas exists in the ambient air, the conductivity of the sensor changes. The higher the concentration of the gas, the higher the conductivity of the sensor. The change in conductivity can be converted into an output signal corresponding to the gas concentration using a simple circuit.