Principle Introduction:
Winsen Electronics manufacture air quality sensor and VOC sensor MQ135 for IAQ monitor application.
Sensitive material of MQ135 gas sensor is SnO2, which with lower conductivity in clean air. When target pollution gas exists, the sensor’s conductivity gets higher along with the gas concentration rising. Users can convert the change of conductivity to correspond output signal of gas concentration through a simple circuit.
MQ135 gas sensor has high sensitivity to ammonia gas, sulfide, benzene series steam, also can monitor smoke and other toxic gases well. It can detect kinds of toxic gases and is a kind of low-cost sensor for kinds of applications.

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

Technical parameters :

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

Model			MQ135
Sensor Type			Semiconductor
Standard Encapsulation			Bakelite, Metal cap
Target Gas			ammonia, sulfide, benzene series steam
Detection range			10～1000ppm( ammonia gas, toluene, Hydrogen, smoke)
Standard Circuit Conditions	Loop Voltage	Vc	≤24V DC
	Heater Voltage	VH	5.0V±0.1V AC or DC
	Load Resistance	RL	Adjustable
Sensor character under standard test conditions	Heater Resistance	RH	29Ω±3Ω（ room tem.）
	Heater consumption	PH	≤950mW
	Sensitivity	S	Rs(in air)/Rs(in 400ppm H2)≥5
	Output Voltage	Vs	2.0V～4.0V（in 400ppm H2）
	Concentration Slope	α	≤0.6(R400ppm/R100ppm H2)
Standard test conditions	Tem. Humidity		20℃±2℃；55%±5%RH
	Standard test circuit		Vc:5.0V±0.1V； VH: 5.0V±0.1V
	Preheat time		Over 48 hours

Reference Circuit :

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