1. Description

  The MQ-D4B combustible gas sensor adopts a multi-layer film manufacturing process, in which heaters and metal oxide semiconductor gas sensing layers are respectively fabricated on both sides of a micro AL2O3 ceramic substrate, and encapsulated in a metal shell. When there is a detected gas in the ambient air, the conductivity of the sensor changes. The higher the concentration of the gas, the higher the conductivity of the sensor. A simple circuit can be used to convert this change in conductivity into an output signal corresponding to the gas concentration

2. Appearance and dimension

3. Technical specifications

4.Test Circuit

  Description: The figure above is the basic test circuit of the MQ-D4B sensor. The sensor needs to apply 2 voltages: heater voltage (VH) and test voltage (VC). VH is used to provide a specific operating temperature for the sensor, and can be powered by a DC power supply or an AC power supply. VRL is the voltage on the load resistor (RL) connected in series with the sensor. VC is the voltage provided for the test of the load resistor RL, and a DC power supply must be used.

5.Characteristic curve of the sensor

1. Typical sensitivity characteristic curve of MQ-D4B

  The vertical axis in the figure is the resistance ratio of the sensor (RS/R0), and the horizontal axis is the gas concentration. RS represents the resistance value of the sensor in gases of different concentrations, and R0 represents the resistance value of the sensor in clean air. All tests in the figure were completed under standard test conditions.

2. Typical temperature and humidity characteristic curve of MQ-D4B

  The vertical axis in the figure is the resistance ratio of the sensor (RS/RS0). RS represents the resistance value of the sensor under different temperatures and humidity conditions containing 5000ppm methane. RS0 represents the resistance value of the sensor under 5000ppm methane and 20℃/55%RH environmental conditions.

3. MQ-D4B linear curve

4. Response recovery curve

5.MQ-D4B long-term stability curve