✍ Sensitive material of MQ137 gas sensor is SnO2, which with lower conductivity in clean air. When the target
combustible gas exist, The sensor's conductivity is more higher along with the gas concentration rising. Please use
simple electrocircuit, Convert change of conductivity to correspond output signal of gas concentration.
MQ137 gas sensor has high sensitity to Ammonia, also to other organic amine. The sensor could be used to detect
different gas which contains Ammonia, it is with low cost and suitable for different application, sensor can be
easily interfaced with Microcontrollers, Arduino Boards, Raspberry Pi etc using an Analog to Digital Converter
(ADC).

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▼ Features :
Stable and Long Life
High sensitivity to Ammonia
Small sensitivity to SnO2
Simple drive circuit
Analog and Digital Outputs
Trigger Level configuration Potentiometer

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▼ Specifications :
Detection Range : 5 ~ 500 ppm of Ammonia
Operating Voltage: DC 5V
Analog Output (AO): 0~5V analog output voltage
Digital Outout (DO): 0V or 5V output
Preheat Duration: 20s
Load Resistance : 2KΩ
Heater Resistance : 31Ω ±5% at Room Temperature
Heating Consumption : < 900mW
Operating Temperature : -10°C ~ 50°C
Weight: 5g
Dimensions: 23 x 19 x 19 mm