Sainsmart MQ137 Semiconductor Sensor for Arduino UNO Mega2560 R3 Raspberry Pi

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. Specifications:   * Model No.: MQ137 * Sensor Type: Semiconductor * Standard Encapsulation: Bakelite (Black Bakelite) * Detection Gas: Ammonia * Concentration: 5-500ppm (Ammonia) CIRCUIT * Loop Voltage(Vc): ?24V DC * Heater Voltage(VH): 5.0V±0.2V AC or DC * Load Resistance(RL): Adjustable CHARACTER * Heater Resistance(RH): 31?±3??Room Tem.? * Heater consumption(PH): ?900mW * Sensing Resistance(Rs): 2K?-15K?(in 50ppm NH3) * Sensitivity(S): Rs(in air)/Rs(5000ppm CH4)?5 * Slope(?): ?0.6(R100ppm/R50ppm NH3) CONDITION * Tem. Humidity: 20?±2??65%±5%RH * Standard test circuit: Vc:5.0V±0.1V? VH: 5.0V±0.1V * Preheat time: Over 48 hours Manual: https://s3-ap-northeast-1.amazonaws.com/sain-amzn/20/20-011-993/MQ137.zip