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MQ-7
MQ-7
| Part Number | MQ-7 |
|---|---|
| Manufacturer | Winsen Electronics / Original Quality Manufacturing Group |
| Category | Sensors, Transducers > Gas Sensors |
| Description | High-sensitivity tin oxide (SnO2) semiconductor CO gas sensor with dual-stage heating cycle, detecting carbon monoxide from 10 ppm to 1000 ppm for precise toxic gas monitoring. |
| Stock Status | In Stock |
| Origin | Original Factory |
Product Overview
The MQ-7 is a reliable SnO2 semiconductor sensor dedicated to carbon monoxide detection. Its conductivity rises proportionally with CO concentration in ambient air.
It adopts alternating dual-temperature heating cycles to boost gas selectivity and suppress cross-interference: low 1.5V heater voltage adsorbs CO for testing, while high 5.0V voltage cleans residual gas and refreshes the sensing layer.
Durable and long-lasting, this sensor fits residential CO alarms, industrial air quality monitors and embedded safety modules.
Core Advantages
Superior Sensitivity to Carbon Monoxide (CO)
Specially calibrated to identify highly dangerous, odorless carbon monoxide gas leaks across a wide concentration window from 10 ppm up to 1000 ppm with quick turnaround response curves.
Dual-Stage Heating Mode for High Selectivity
By cyclically switching between sensing and thermal cleaning windows, the sensor minimizes false triggers caused by alcohol, LPG, or ambient moisture interference.
Long Life & Exceptional Operational Stability
Constructed with durable tin dioxide semiconductor chemistry and a heavy-duty stainless steel mesh enclosure, ensuring stable electrical performance over years of continuous deployment.
Straightforward Analog Output Conditioning
Outputs a simple, linear change in resistance relative to gas density, making it easy to integrate with simple voltage divider circuits and standard microcontrollers like Arduino, STM32, or PIC platforms.
Key Specifications
| Brand | Winsen / Standard Sensor Component Series |
|---|---|
| RoHS Status | RoHS Compliant / Lead-Free Components |
| EDA/CAD Model | 3D Footprint Models and Sample Schematics available upon request |
| Warranty | 1-Year Standard Quality Warranty |
| Package / Case | Standard 6-Pin Bakelite / Plastic Base with Stainless Steel Double Layer Mesh (Style: MQ-7 Capsule) |
| Pin Count | 6 through-hole pins (2 heater pins + 4 signal circuit pins) |
| Mounting Type | Through-Hole Pin Insertion (THT) / Pin Socket Compatible |
| Surface Marking / Silkscreen | MQ-7 Marking |
| Sensitive Material | Tin Dioxide ($SnO_2$) semiconductor layer with noble metal catalyst |
| Target Gas | Carbon Monoxide (CO Gas) |
| Detection Range | 10 ppm to 1000 ppm CO |
| Standard Circuit Voltage ($V_C$) | ≤ 10 V DC or AC |
| Heater Voltage ($V_H$) | 5.0 V ± 0.1 V (High Phase) / 1.5 V ± 0.1 V (Low Phase) AC or DC |
| Cycle Timing | High temp cleaning phase: 60 s; Low temp detection phase: 90 s |
| Heater Resistance ($R_H$) | 31 Ω ± 3 Ω (at room temperature) |
| Heater Consumption ($P_H$) | Approximately 350 mW |
| Sensing Resistance ($R_S$) | 2 kΩ to 20 kΩ (in 100 ppm CO) |
| Response Time | ≤ 30 s (reach stable output in 100 ppm CO environment) |
| Recovery Time | ≤ 60 s (return to baseline resistance after gas removal) |
| Operating Ambient Temperature | -10 ℃ ~ +50 ℃ |
| Operating Ambient Humidity | 20% RH ~ 90% RH (non-condensing) |
| Preheat Time | Over 48 Hours (Recommended initial seasoning for peak precision stability) |
| Service Life | Up to 5 years under normal cyclic heating operation |
Typical Applications
- Residential Domestic Carbon Monoxide Detection Systems and Portable Gas Leak Pagers
- Industrial Toxic Gas Monitoring Networks, Factory Air Treatment Control Loops, and Boiler Rooms
- Commercial Car Park Ventilation Triggers and Fire / Smoke Safety Detection Systems
- Multi-Gas Indoor Air Quality (IAQ) Monitors and Smart Home Environmental Sensing Nodes
- Environmental Safety Field Equipment and Laboratory Gas Analysis Instruments
Order & Shipping Info
| Minimum Order Quantity (MOQ) | 1 Piece |
|---|---|
| Shipping Time | Shipped within 1-2 business days |
| Delivery Time | 3-7 working days worldwide |
| Shipping Methods | DHL, UPS, FedEx, EMS |
| Payment Methods | T/T (Bank Transfer), PayPal, Credit Card, Western Union |
Technical Support
For datasheet, sample requests, stock check, or bulk pricing, please use the Quick Inquiry form. We will reply within 24 hours.
Frequently Asked Questions
Q1: Is your currently available stock of the MQ-7 sensor 100% genuine original factory material?
A: Yes, we guarantee that all MQ-7 gas sensor units in our warehouse are 100% authentic, brand-new, original factory components. Every delivery batch undergoes factory traceability audits and is packaged inside durable, moisture-proof containers to preserve element coatings.
Q2: Why does the MQ-7 require a dual-voltage heating cycle instead of a continuous 5V supply?
A: The dual-heating profile is critical for accurate CO measurement. Carbon monoxide adsorbs optimally onto the sensor material during the low-temperature phase. The high-temperature phase cleans the sensor by vaporizing residual gases, resetting the surface for the next cycle. Operating continuously at 5V prevents proper target gas adsorption, making accurate CO measurement impossible.
Q3: What is the purpose of the 48-hour preheating or “burn-in” period listed in the specifications?
A: During long storage periods, ambient moisture and atmospheric gases settle on the tin dioxide element. The initial 48-hour preheat bakes off these impurities, stabilizing the chemical structure of the internal sensing layer. This process is essential to achieve accurate base resistance values and prevent false alarms during initial deployment.
Q4: Can the MQ-7 gas sensor distinguish between Carbon Monoxide (CO) and common household alcohols?
A: While the MQ-7 exhibits high sensitivity to Carbon Monoxide, semiconductor sensors can cross-react with high concentrations of organic vapors like alcohol. Utilizing the specified dual-heating loop significantly reduces this cross-sensitivity, allowing the sensor to isolate CO signatures under standard operating conditions.
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