Principle Introduction:
Winsen Electronics is original manufacturer of MQ-7B Carbon Monoxide gas sensor, CO Gas sensor, with 80% market share in gas sensor field.
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.

Applications :
It is widely used in domestic CO gas leakage alarm, industrial CO gas alarm and portable CO gas detector.

Technical parameters :

Tips:For more parameter information, please refer to the latest manual provided by salesman.

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	≤10V DC
	Heater Voltage	VH	5.0V±0.1V AC or DC（High tem.） 1.5V±0.1V AC or DC（Low tem.）
	Heater Time	TL	60 S±1S（High tem.）， 90 S±1S（Low tem.）
	Load Resistance	RL	Adjustable
Sensor character under standard test conditions	Heater Resistance	RH	29Ω±3Ω（room tem.）
	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 tem.）： 5.0V±0.1V； VH （Low tem.）： 1.5V±0.1V
	Preheat time		Over 48 hours

Reference Circuit :

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