The Winsen MQ-4 combustible gas sensor manual provides product description, technical specifications, circuit diagram, and safety precautions.
The MQ-4 sensor uses a tin dioxide (SnO2) semiconductor material that changes its conductivity when combustible gases such as methane are present. A simple circuit converts the resistance change into an output voltage proportional to gas concentration.
The manual lists the sensor’s technical parameters, recommended heating and test voltages, output voltage range, and environmental limits. It also includes a basic test circuit, wiring guidelines, and detailed precautions for handling, storage, and operation to ensure reliable performance. This manual is written in Chinese.
| Detection gas | Methane |
|---|---|
| Detection concentration | 300–10000 ppm |
| Heating voltage | 5.0 V ± 0.1 V |
| Heating power | ≤950 mW |
| Output voltage range | 2.5 V–4.0 V at 5000 ppm CH4 |
The MQ-4 sensor is designed to detect methane.
The sensor requires a pre‑heat time of at least 48 hours.
Avoid exposure to volatile silicon compounds, corrosive gases, water, high voltage, and excessive vibration or impact.