Sensor

MQ-136 PDF – Semiconductor Gas Sensor – Hanwei

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Part Number: MQ-136, MQ136

Function: Semiconductor Gas Sensor

Manufacturer: HANWEI ELECTRONICS

Images:MQ-136 pdf gas sensor

Description

MQ-136 is Gas Sensor. The MQ-136 is a type of gas sensor module that is designed to detect the presence of hydrogen sulfide gas (H2S) in the air. The MQ series of gas sensors are widely used for various gas detection applications and are commonly found in industrial settings, environmental monitoring systems, safety equipment, and more.

1. Gas Sensor: The core component of the module is the gas sensor itself, which is sensitive to hydrogen sulfide gas. The sensor’s electrical resistance changes in the presence of the target gas.

2. Heater Element: The gas sensor usually includes a built-in heater element. The heater heats the sensor to a specific operating temperature, enhancing its sensitivity and responsiveness to gas detection.

3. Signal Conditioning Circuitry: The module often contains signal conditioning circuitry that converts the change in sensor resistance into a measurable voltage or current output. This output can be interfaced with microcontrollers, data loggers, or other monitoring systems.

Features

  • High sensitivity to hydrogen sulfide (H2S)
  • Fast response and recovery characteristics
  • Stable performance and long operating life
  • Simple drive circuit
  • Built-in heater element for stable operation
  • SnO2 semiconductor sensing technology
  • Wide detection range for H2S gas
  • Suitable for continuous gas monitoring
  • Easy interface with microcontrollers and ADC circuits
  • Reliable performance for industrial gas detection

MQ-136 datasheet pinout

Design Notes

  • Allow sufficient preheating time before taking gas concentration measurements
  • Adjust the load resistance to optimize sensitivity for the intended H2S concentration range
  • Avoid exposing the sensor to silicone vapors or corrosive chemicals that may degrade performance
  • Install the sensor in locations with adequate airflow for accurate gas sampling
  • Periodic calibration is recommended for long-term measurement accuracy

Typical Circuit Usage

  • Hydrogen sulfide gas leak detectors
  • Industrial safety monitoring equipment
  • Air quality monitoring systems
  • Environmental monitoring stations
  • Microcontroller-based gas detection circuits
  • IoT environmental sensing devices

How to Choose This Part

  • Select for applications requiring selective detection of hydrogen sulfide gas
  • Suitable for industrial and environmental gas monitoring
  • Choose when a low-cost semiconductor gas sensor is preferred
  • Ideal for Arduino, ESP32, Raspberry Pi, and embedded monitoring systems
  • Consider routine calibration for quantitative gas concentration measurements

Applications

  • Hydrogen sulfide (H2S) gas detection
  • Industrial safety systems
  • Air quality control equipment
  • Building and office environmental monitoring
  • Gas leakage alarm systems
  • Wastewater treatment facilities
  • Chemical processing plants
  • Smart environmental monitoring devices

Alternative / Equivalent Products

  • MQ-135
  • MQ-137
  • MQ-2
  • MiCS-4514
  • ZE07-H2S
  • ME3-H2S Electrochemical Sensor

MQ-136 PDF Datasheet

MQ135 Datasheet PDF – Semiconductor Gas Sensor

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The MQ135 is a semiconductor gas sensor widely used for detecting air quality and harmful gases. It belongs to the MQ sensor family, which uses SnO₂ (tin dioxide) as the sensing material.

Function: Gas Sensor

Package: 6 Pin Module type

Manufacturer: Futurlec

Image:

MQ135 datasheet

Description

The MQ135 is a semiconductor gas sensor designed to detect air quality-related gases such as NH3, NOx, alcohol, benzene, smoke, and CO2 equivalents in indoor environments. It employs a heated SnO2 sensing element that offers high sensitivity, wide detection range, and stable response characteristics. This sensor is commonly used in air quality monitors, smart home systems, and environmental sensing projects.

Features

  • Wide detecting scope
  • Fast response and high sensitivity
  • Stable and long operational life
  • Simple drive circuit
  • Wide detection range for indoor air quality monitoring
  • SnO2 semiconductor sensing element
  • Good repeatability and long-term stability
  • Suitable for continuous gas monitoring

Principle of Operation

The MQ-135 sensor works on the chemiresistor principle:

1. Sensing Material: SnO₂ changes its resistance when exposed to oxidizing or reducing gases.

2. Gas Detection: The sensor’s resistance decreases with the presence of target gases.

3. Heater Element: Built-in heater maintains the sensing material at the required working temperature (~200–300°C) to improve reaction and sensitivity.

4. Output Signal: Analog voltage or resistance change, which can be read by a microcontroller ADC or converted to PPM (parts per million) with calibration.

MQ135 Pinout

components

1. Gas sensing : layer SnO2

2. Electrode : Au

3. Electrode line : Pt

4. Heater coil : Ni-Cr alloy

5. Tubular ceramic : Al2O3

6. Anti-explosion network : Stainless steel gauze (SUS316 100-mesh)

7. Clamp ring : Copper plating Ni

8. Resin base : Bakelite

9. Tube Pin : Copper plating Ni

Design Notes

  • Allow an adequate preheating period before taking measurements for maximum accuracy
  • Use a suitable load resistor to optimize sensitivity for the target gas concentration
  • Avoid exposure to silicone vapors and corrosive gases that may damage the sensing element
  • Ensure good airflow around the sensor during operation
  • Periodic calibration is recommended for quantitative air quality measurements

Applications

They are used in air quality control equipments for buildings/offices, are suitable for detecting of NH3, NOx,  alcohol,  Benzene,  smoke, CO2 , etc.

1. Air Quality Monitoring: Indoor/outdoor air quality sensors, smart home air purifiers

2. Industrial Safety: Detecting harmful gases in factories

3. Environmental Monitoring: Measuring urban pollution, CO₂, NOx levels

4. Educational Projects: Used in DIY electronics to demonstrate gas detection

5. Vehicle Emissions Monitoring: Detecting exhaust gases and VOCs

 

Comparison with Other MQ Sensors

Sensor Target Gas Sensitivity Application
MQ-2 LPG, H₂, Methane, Smoke High for flammable gases Gas leak detection, fire alarms
MQ-6 LPG, Butane, Propane High for LPG/Propane Home gas detectors
MQ-7 CO (Carbon Monoxide) High for CO CO detection, air quality
MQ-135 NH₃, NOx, CO₂, Benzene, Smoke High for harmful air gases Air quality monitoring, pollution detection

Other data sheets are available within the file: MQ-135

MQ135 Datasheet PDF Download


MQ135 pdf

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