MQ-7B Semiconductor Sensor for Carbon Monoxide

For residential and industrial CO leakage detection.

Applications :

*CO alarm
*Portable co detector

Product Advantages:

*Low cost
*10 years lifetime
*Fast response time
*Simple drive circuit

Product Description:

Sensitive material of MQ-7B gas sensor is SnO2, which with lower conductivity in clean air. It make detection by method of cycle high and low temperature, and detect CO at low temperature (heated by 1.5V).The sensor’s conductivity gets higher along with the CO gas concentration rising. At high temperature (heated by 5.0V),it cleans the other gases adsorbed at low temperature. Users can convert the change of conductivity to correspond output signal of gas concentration through a simple circuit.

Technical Parameters:

Model			MQ-7B
Sensor Type			Semiconductor
Standard Encapsulation			Plastic cap
Target Gas			carbon monoxide
Detection range			10～500ppm CO
Standard Circuit Conditions	Loop Voltage	Vc	≤24V DC

	Heater Voltage	VH	5.0V±0.1V AC or DC (High temp.)
			1.5V±0.1V AC or DC (Low temp.)
	Heater Time	TL	60 S±1S (High temp.)
			90 S±1S (Low temp.)
	Load Resistance	RL	Adjustable
Sensor character under standard test conditions	Heater Resistance	RH	29Ω±3Ω (room temp.)
	Heater consumption	PH	≤900mW
	Sensitivity	S	Rs(in air)/Rs(in 150ppm CO)≥5
	Output Voltage	Vs	2.5V～4.3V (in 150ppm CO)
	Concentration Slope	α	≤0.6(R300ppm/R50ppm CO)
Standard test conditions	Tem. Humidity		20℃±2℃；55%±5%RH

	Standard test circuit		Vc:5.0V±0.1V；
			VH (High temp.): 5.0V±0.1V
			VH (Low temp.): 1.5V±0.1V
	Preheat time		Not less than 48 hours
	O2 content		21%（not less than 18%）
			O2 concentration effects initial value, sensitivity and repeatability.
	Preheat time		Over 48 hours
Lifespan			10 years