MQ-137 Ammonia Gas NH3 Sensor Module

The MQ-137 Ammonia Gas NH3 Sensor Module is designed to monitor the concentration of ammonia gas (NH3). It utilizes tin dioxide (SnO2) as the gas-sensitive material, which exhibits low conductivity in clean air. However, when ammonia is present, the sensor's conductivity increases proportionally to the concentration of ammonia in the air. Here are the features, specifications, and applications of the MQ-137 sensor module:

  Features:  

• Wide detecting scope
• Fast response time (less than 1 second)
• High sensitivity (3%)
• Operating voltage: DC5V
• Stable and long life
• Analog output voltage: 0V to 5V
• Digital output voltage: 0V or 5V (TTL Logic)
• Can be used as a digital or analog sensor
• Adjustable sensitivity of digital output using an onboard potentiometer
• Low TTL output valid signal (signal light is on when output is low, suitable for direct connection to MCU or relay module)
• Voltage of analog output increases with concentration
• Arduino compatible

  Specifications:  

• • perating Voltage: 5V DC
  • Gas Detected: Ammonia (NH3)
  • Detection Range: 5-500 ppm
  • Heater Resistance: 31Ω ± 3Ω at room temperature
  • Heater Consumption: 900mW
  • Sensing Resistance: 2KΩ - 15KΩ in 50ppm NH3 concentration
  • Sensitivity (S): Rs (in air) / Rs (in 5000ppm CH4) ≥ 5
  • Slope (α): 0.6 (Ratio of R100ppm / R50ppm NH3)
  • Output Voltage (V): 0 to 5V linear analog output
  • Dimensions: 35mm (Length) x 20mm (Width) x 28mm (Height)
  • Weight: 10g
    

  Applications:  

• Gas detection of NH3 or CO
• Air quality monitoring
• Gas leak alarm systems
• Safety standard maintenance
• Environmental standards monitoring in hospitals

  Package Includes:  

• 1 x MQ-137 Ammonia Gas NH3 Sensor Module

To use the MQ-137 sensor module, power it with 5V and observe the power LED. When no gas is detected, the output LED remains off and the digital output pin is at 0V. Pre-heat the sensor before use. Introduce the sensor to the gas you want to detect and adjust the potentiometer until the output LED goes high.