MQ303A alcohol gas sensor belongs to the MQ gas sensor family. MQ303A is a Metal Oxide Semiconductor (MOS) type of sensor, originally belonging to the class of chemresistors; a class of resistance-based sensors in which the sensing is based on the change of resistance of the sensing material when exposed to alcohol. MQ303A is a heater-driven sensor. That’s why it is enclosed in two layers of fine stainless steel mesh called an Anti-explosion network. This ensures that the heater element inside the sensor will not cause an explosion, as we are sensing flammable gas (alcohol).
MQ303A gas sensor has a high sensitivity to Alcoholic gases and possesses a fast trigger response time. The sensor’s output is analog resistance corresponding to the concentration of Alcohol gas in the vicinity. The drive circuit is very simple; all that is required to do is to power up the heater coil with 5V, add a load resistance, and connect the output to an ADC.
MQ303A Gas Sensor Key Features
- High sensitivity to Alcoholic Gases and fumes
- Stable and Long Life
- Detection Range: 10 – 300 ppm, NH3(Ammonia gas), 10 – 1000 ppm, Benzene, 10 – 300 Alcohol
- Heater Voltage: 5.0V
- Standard Encapsulation: Bakelite
- Fast response characteristics
- With mounting holes for easy permanent installation
- Main chip: LM393 Voltage comparator
- Dimensions: 18mm Diameter, 17mm High excluding pins, Pins – 6mm High
- Long life and low cost
MQ303A Gas Sensor Pinout
| Pin Name | Pin No. | Description |
|---|---|---|
| VCC | 1 | This pin powers the module, typically the operating voltage is +5V |
| GND | 2 | Used to connect the module to the system ground |
| DO | 3 | You can also use this sensor to get digital output from this pin, by setting a threshold value using the potentiometer |
| AO | 4 | This pin outputs 0-5V analog voltage based on the intensity of the gas. |
Specifications
- Heater voltage: 0.9V ± 0.10V
- Circuit voltage: Less than 6 V
- Load resistance: Variable
- Heater resistance: 4.5 Ω ± 0.5 Ω
- Heater current: Less than 130 mA
- Heater power consumption: Less than 130 mW
- Power dissipation of sensing element: Less than 10 mW
- Operating temperature: -10 C to 50 C
- Storage temperature: -20 C to 70 C
- Relative humidity: Less than 70% RH
- Oxygen concentration: 21%±1%(Standard condition)
- Sensor resistance: (20kΩ to 200 kΩ)
- Sensitivity: (0.50 ± 0.15)
- Frequency: 100 cpm
- Vertical amplitude: 4 mm
Applications
- Breathalyzer for alcohol blood level estimation.
Datasheet
You can download the datasheet for MQ303A Alcohol Sensor Module by clicking the link given below:
See Also: CD4059 Program Divide-by-N Counter | DS3231 Precision I2C Real-Time Clock Module | MT8870D Integrated ISO2-CMOS DTMF Receiver Module
