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MQ2:

(Gas leak monitoring devices for homes and factories, suitable for detection of liquefied gases, butane, propane, methane, alcohol, hydrogen, fumes, etc.)

Gas: smoke
Detection range: 300 to 10000ppmm
Characteristic gas: 1000ppmm isobutane
Sensitivity: R in air/Rin typical gas≥5
Sensitive body resistance: 1KΩ to 20KΩ in 50ppm toluene
Response time: ≤10s
Recovery time: ≤30s
Heating resistance: 31Ω±3Ω
Heating current: ≤180mA
Heating voltage: 5.0V ± 0.2V
Heating power: ≤900mW
Measuring voltage: ≤24V

MQ-2 gas sensor sensitive material used in the clean air low conductivity tin oxide (SnO2). When there is the environment in which the combustible gas sensor, conductivity sensor with increasing concentration of combustible gases in air increases. Using a simple circuit to convert the change in conductivity of the gas concentration corresponding to the output signal. MQ-2 gas sensor high on gas, propane, hydrogen sensitivity of detection of natural gas and other flammable vapors are also very good. This sensor can detect a variety of flammable gas, is a low-cost sensors for a variety of applications.

Gas may be used in homes and factories leakage monitoring device suitable for the detection of gas, butane , propane , methane , smoke , etc.

Using high-quality dual-panel design, with power indicator and TTL signal output instructions;
The switching signal having a DO (TTL) output and analog output AO ;
TTL output valid signal is low . ( Low-level signal when the output light can be directly connected to the microcontroller or relay module )
Analog output voltage with the higher concentration of higher voltage.
A gas, natural gas, city gas , smoke better sensitivity.
There are four screw holes for easy positioning ;
Has a long life and reliable stability
Rapid response and recovery characteristic

Input voltage : DC5V Power consumption ( current ): 150mA
DO output : TTL digital 0 and 1 ( 0.1 and 5V)
AO output :0.1-0 .3 V ( relative to pollution ) , the maximum concentration of a voltage of about 4V
Special note: After the sensor is powered , needs to warm up around 20S, measured data was stable , heat sensor is a normal phenomenon , because the internal heating wire , if hot is not normal .

VCC: positive power supply (5V)
GND: power supply is negative
DO: TTL switching signal output
AO: analog signal output

MQ-2B

Product description:

The gas sensing material used in the MQ-2B gas sensor is tin dioxide (SnO2) with lower conductivity in clean air. When there is a flammable gas in the environment where the sensor is located, the conductivity of the sensor increases as the concentration of flammable gas in the air increases. The change in conductivity can be converted to an output signal corresponding to the gas concentration using a simple circuit.

The MQ-2B gas sensor is highly sensitive to propane and smoke and is ideal for the detection of natural gas and other flammable vapors. This sensor detects multiple flammable gases and is a low-cost sensor for a wide range of applications.

Features:

This product has good sensitivity to propane, smoke, etc. in a wide concentration range, and has the advantages of long life, low cost, and simple driving circuit.

Application:

Widely used in household gas leak alarms, industrial combustible gas alarms and portable gas detection instruments.

Parameter:

Detection gas: combustible gas, smoke
Detection concentration: 300 ~ 10000ppm (combustible gas)
Loop voltage Vc: ≤24V DC
Heating voltage VH : 5.0V ± 0.1V AC or DC
Load resistance RL: adjustable
Heating resistance RH : 29 Ω ± 3 Ω (room temperature)
Heating power consumption PH : ≤900mW
Sensitivity S: Rs (in air) / Rs (2000ppm C3H8) ≥ 5
Output voltage Vs : 2.5V ~ 4.0V (in 2000ppmC3H8)
Concentration slope α: ≤0.6 (R3000ppm/R1000ppm C3H8)
Temperature, humidity: 20 °C ± 2 ° C; 55% ± 5% RH
Standard test circuit: Vc: 5.0V ± 0.1V; VH: 5.0V ± 0.1V
Warm-up time: no less than 48 hours
Oxygen content: 21% (not less than 18%, (oxygen concentration will affect the initial value, sensitivity and repeatability of the sensor, please consult when using at low oxygen concentration)
Life expectancy: 10 years

Note:The figure above shows the basic test circuit for the MQ-2B sensor. The sensor requires two voltages to be applied: heater voltage (VH) and test voltage (VC). The VH is used to provide a specific operating temperature for the sensor, either DC or AC. The VRL is the voltage across the load resistor (RL) of the sensor in series. VC is the voltage for testing the load resistor RL and requires a DC power supply.