Manual Version: 1.6 Valid from: 2021-07-01 Zhengzhou Winsen Electronics Technology Co.,

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 the components inside of the sensor, we shall not...

Zhengzhou Winsen Electronics Technology Co., Ltd MQ135 Semiconductor Sensor for Air Quality Profile Sensitive material of MQ135 gas sensor is SnO2, which with lower conductivity in clean air. When target pollution 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. MQ135 gas sensor has high sensitivity to ammonia gas, sulfide, benzene series steam, also can monitor smoke and other toxic gases well. It can detect kinds of toxic gases and...

Zhengzhou Winsen Electronics Technology Co., Ltd Basic Circuit Fig2. MQ135 Test Circuit Instructions: The above fig is the basic test circuit of MQ135.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 adopts DC power. Calculation formula: Resistance of Sensitive materials (Rs)=(Vc/VRL-1)×RL Power consumption of Sensitive...

Zhengzhou Winsen Electronics Technology Co., Ltd Fig5 shows the VRL in H2 gas with different concentration. Fig5 shows the changing of VRL in the process of putting The resistance load RL is 4.7 KΩ and the test is finished in the sensor into target gas and removing it out. standard test conditions. Fig7.long-term Stability Test is finished in standard test conditions, the abscissa is observing time and the ordinate is VRL. 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...

Zhengzhou Winsen Electronics Technology Co., Ltd www.winsen-sensor.com The sensors performance will be changed badly if sensors be sprayed polluted by alkali metals salt especially brine, or be exposed to halogen such as fluorine. 1.4 Touch water Sensitivity of the sensors will be reduced when spattered or dipped in water. 1.5 Freezing Do avoid icing on sensor’s surface, otherwise sensing material will be broken and lost sensitivity. 1.6 Applied higher voltage Applied voltage on sensor should not be higher than stipulated value, even if the sensor is not physically damaged or broken, it causes...

Zhengzhou Winsen Electronics Technology Co., Ltd www.winsen-sensor.com If sensors meet strong concussion, it may lead its lead wire disconnected. 2.7 Usage Conditions 2.7.1For sensor, handmade welding is optimal way. The welding conditions as follow:     Soldering flux: Lead-free and halogen-free soldering flux homothermal soldering iron Temperature： ≤350℃ Time：less than 3 seconds If disobey the above using terms, sensors sensitivity will reduce. Zhengzhou Winsen Electronics Technology Co., Ltd Add: No.299, Jinsuo Road, National Hi-Tech Zone, Zhengzhou 450001 China Tel: +86-371-67169097/67169670...