MEMS VOC Gas Sensor （Model No.:GM-502B） Manual Version: 2.2 Valid from: 2020.08.25 Zhengzhou Winsen Electronics Technology Co., Lt

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 the customer 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...

GM-502B MEMS VOC Gas Sensor Product description MEMS VOC gas sensor is using MEMS micro-fabrication hot plate on a Si substrate base, gas-sensitive materials used in the clean air with low conductivity metal oxide semiconductor material. When the sensor exposed to gas atmosphere, the conductivity is changing as the detected gas concentration in the air. The higher the concentration of the gas, the higher the conductivity. Use simple circuit can convert the change of conductivity of the gas concentration corresponding to the output signal. Characters MEMS technology, strong structure Low power...

Sensor Structure Diagram Recommend Circuit Instructions: The above fig is the basic test circuit of GM-502B.The sensor requires two voltage inputs: heater voltage (VH) and circuit voltage (VC). VH is used to supply specific working temperature to the sensor and it can adopt DC or AC power. Vout 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 ad

Sensitivity Characteristics: Fig3.Typical Sensitivity Curve Rs means resistance in target gas with different concentration, R0 means resistance of sensor in clean air. All tests are finished under standard test conditions. Fig4.Typical temperature/humidity characteristics Rs means resistance of sensor in 50ppm alcohol gas under different temp. and humidity. Rso means resistance of the sensor in 50ppm alcohol gas under 20℃/55%RH. The output in above Fig is the voltage of RL which is in The output in above Fig is the voltage of RL which is in series with sensor. All tests are finished under standard...

Long-term stability Fig7.long-term Stability Test is finished in standard test conditions, the abscissa is observing time and the ordinate is voltage output of RL. Instructions: 1. Preheating time Sensor’s resistance may drift reversibly after long-term storage without power. It need to preheat the sensor to reach inside chemical equilibrium. Preheating voltage is same with heating voltage VH. The suggested preheating time as follow: Storage Time Suggested aging time Less than one month No less than 24 hours No less than 48 hours More than six months No less than 72 hours 2. Calibration Sensor’s...

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 voltage Applied voltage on sensor should not be higher than 120mW, it will cause irreversible heater damaged, also hurt from static, so anti-static precautions should be taken when touching sensors. 2. Following conditions should be avoided 2.1 Water Condensation Indoor conditions, slight water condensation will influence sensors’ performance lightly. However, if water condensation on sensors...