MQ138 VOC Gas Sensor

The Winsen MQ138 is a semiconductor gas sensor designed for the detection of Volatile Organic Compounds (VOCs). Its sensitive material is SnO2, which has low conductivity in clean air. When VOC gases are present, the sensor’s conductivity increases as the gas concentration rises. This sensor has high sensitivity to toluene, acetone, and alcohol, and can also monitor hydrogen and other organic vapors. It is a low-cost solution for a variety of applications, with a simple drive circuit. The sensor is widely used in domestic and industrial VOC gas alarms and portable detectors.

Specification :

• Model: MQ138
• Sensor Type: Semiconductor
• Target Gases: Toluene, acetone, alcohol, hydrogen, and other organic vapor
• Detection Range: 5 to 500 ppm
• Loop Voltage (Vc): ≤24V DC
• Heater Voltage (VH): 5.0V ± 0.1V AC or DC
• Heater Consumption (PH): <900mW
• Heater Resistance (RH): 29Ω±3Ω (room temp.)
• Preheat Time: Over 48 hours
• Encapsulation: Bakelite, Metal cap