Zhengzhou Winsen Electronics Technology Co., Ltd Manual Version: 1.6 Valid from: 2021-7-1 Zhengzhou Winsen Electronics Technology Co., Ltd Email: sales@winsensor.

Zhengzhou Winsen Electronics Technology Co., Ltd Statement This manual copyright belongs to Zhengzhou Winsen Electronics Technology Co., LTD. Without the written permission, any part of this manual shall not be copied, translated, stored in database or retrieval system, also can’t spread through electronic, copying, record ways. Thanks for purchasing our product. In order to let customers use it better and reduce the faults caused by misuse, please read the manual carefully and operate it correctly in accordance with the instructions. If users disobey the terms or remove, disassemble, change...

Zhengzhou Winsen Electronics Technology Co., Ltd MQ138 VOC Gas Sensor Profile Sensitive material of MQ138 gas sensor is SnO2, which with lower conductivity in clean air. When VOC gas exists, the sensor’s conductivity gets higher along with the gas concentration rising. Users can convert the change of conductivity to correspond output signal of gas concentration through a simple circuit. MQ138 gas sensor has high sensitivity to toluene, acetone, alcohol, methanol, also can monitor hydrogen and other organic vapour well. It can detect kinds of organic gases and is a kind of low-cost sensor for...

Zhengzhou Winsen Electronics Technology Co., Ltd Basic Circuit Fig2. MQ138 Test Circuit Instructions: The above fig is the basic test circuit of MQ138.The sensor requires two voltage inputs: heater voltage (VH) and circuit voltage(VC). VH is used to supply standard working temperature to the sensor and it can adopt DC or AC power, while VRL is the voltage of load resistance RL which is in series with sensor. Vc supplies the detect voltage to load resistance RL and it should adopt DC power. Alcohol Air Toluene Acetone Description of Sensor Characters Email: [email protected]

Zhengzhou Winsen Electronics Technology Co., Ltd Fig5.Sensitivity Curve Fig5 shows the VRL in toluene with different concentration. The resistance load RL is 4.7 KΩ and the test is finished in Fig6.Response and Resume Fig6 shows the changing of VRL in the process of putting the sensor into target gas and removing it out. standard test conditions. Cautions 1 .Following conditions must be prohibited 1.1 Exposed to organic silicon steam Sensing material will lose sensitivity and never recover if the sensor absorbs organic silicon steam. Sensors must avoid exposing to silicon bond, fixature, silicon...

Zhengzhou Winsen Electronics Technology Co., Ltd 2.1 Water Condensation Indoor conditions, slight water condensation will influence sensors’ performance lightly. However, if water condensation on sensors surface and keep a certain period, sensors’ sensitive will be decreased. 2.2 Used in high gas concentration No matter the sensor is electrified or not, if it is placed in high gas concentration for long time, sensors characteristic will be affected. If lighter gas sprays the sensor, it will cause extremely damage. 2.3 Long time storage The sensors resistance will drift reversibly if it’s stored...