MQ138 - Hanwei

MQ138 Semiconductor Sensor

MQ138 Semiconductor Sensor for Organic Steam Sensitive material of MQ138 gas sensor is SnO2, which with lower conductivity in clean air. When the target Organic Steam 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 con.

Features

Bakelite) Detection Gas Toluene, Acetone, Ethanol, H2 Concentration 5-500ppm Circuit Loop Voltage Heater Voltage Load Resistance Vc VH RL ≤24V DC 5.0V±0.2V AC or DC Adjustable Heater Resistance RH 31Ω±3Ω（Room Tem.） Character Heater consumption Sensing Resistance PH ≤900mW Rs 2KΩ-20KΩ(in 50ppm Toluene ) Sensitivity S Rs(in air)/Rs(50ppm Toluene)≥3 Slope α ≤0.6≤0.6(R100ppm/R50ppm Toluene) Tem. Humidity 20℃±2℃；65%±5%RH Condition Standard test circuit Vc: 5.0V±0.1V； VH: 5.0V±0.1V Preheat time Over 48 hours Power of Sensitivity body(Ps): Ps=Vc2×Rs/(Rs+RL)2 RL VH GND The ab.