製品の詳細 ( Datasheet PDF )
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MQ136 Semiconductor Sensor for Sulfur Dioxide
Sensitive material of MQ136 gas sensor is SnO2, which with lower conductivity in clean air. When the
target SO2 gas exist, the sensor’s conductivity is more higher along with the gas concentration rising.
Please use simple electrocircuit, Convert change of conductivity to correspond output signal of gas
MQ136 gas sensor has high sensitity to SO2, also could be used to detect other vapor which
contains Sulfur. It has low sensitivity to normal combustible gases, which is with low cost and suitable for
* Good sensitivity to SO2
* Long life and low cost
* Simple drive circuit
* Domestic SO2 concentration detector
* Industrial SO2 leakage detector
* Portable SO2 detector
Basic test loop
Bakelite (Black Bakelite)
2KΩ-20KΩ(in 50ppm SO2)
Sensitivity S Rs(in air)/Rs(50ppm SO2)≥3
Condition Standard test circuit
Over 48 hours
Power of Sensitivity body(Ps): Ps=Vc2×Rs/(Rs+RL)2
The above is basic test circuit of the sensor.
The sensor need to be put 2 voltage,
heater voltage（VH）and test voltage（VC）.
VH used to supply certified working
temperature to the sensor, while VC used
to detect voltage (VRL) on load resistance
（RL）whom is in series with sensor. The
sensor has light polarity, Vc need DC
power. VC and VH could use same power
circuit with precondition to assure
performance of sensor. In order to make
the sensor with better performance,
suitable RL value is needed:
1 Following conditions must be prohibited
1.1 Exposed to organic silicon steam
Organic silicon steam cause sensors invalid, sensors must be avoid exposing to silicon bond,
fixature, silicon latex, putty or plastic contain silicon environment
1.2 High Corrosive gas
If the sensors exposed to high concentration corrosive gas (such as H2Sz, SOX，Cl2，HCl etc), it will
not only result in corrosion of sensors structure, also it cause sincere sensitivity attenuation.
1.3 Alkali, Alkali metals salt, halogen pollution
The sensors performance will be changed badly if sensors be sprayed polluted by alkali metals salt
especially brine, or be exposed to halogen such as fluorin.
1.4 Touch water
Sensitivity of the sensors will be reduced when spattered or dipped in water.
Do avoid icing on sensor’surface, otherwise sensor would lose sensitivity.
1.6 Applied voltage higher
Applied voltage on sensor should not be higher than stipulated value, otherwise it cause down-line or
heater damaged, and bring on sensors’ sensitivity characteristic changed badly.
1.7 Voltage on wrong pins
For 6 pins sensor, if apply voltage on 1、3 pins or 4、6 pins, it
will make lead broken, and without signal when apply on 2、4 pins
2 Following conditions must be avoided
2.1 Water Condensation
Indoor conditions, slight water condensation will effect sensors performance lightly. However, if water
condensation on sensors surface and keep a certain period, sensor’ sensitivity will be decreased.
2.2 Used in high gas concentration
No matter the sensor is electrified or not, if long time placed in high gas concentration, if will affect
2.3 Long time storage
The sensors resistance produce reversible drift if it’s stored for long time without electrify, this drift is
related with storage conditions. Sensors should be stored in airproof without silicon gel bag with clean air.
For the sensors with long time storage but no electrify, they need long aging time for stbility before using.
2.4 Long time exposed to adverse environment
No matter the sensors electrified or not, if exposed to adverse environment for long time, such as
high humidity, high temperature, or high pollution etc, it will effect the sensors performance badly.
Continual vibration will result in sensors down-lead response then repture. In transportation or
assembling line, pneumatic screwdriver/ultrasonic welding machine can lead this vibration.
If sensors meet strong concussion, it may lead its lead wire disconnected.
For sensor, handmade welding is optimal way. If use wave crest welding should meet the following
2.7.1 Soldering flux: Rosin soldering flux contains least chlorine
2.7.2 Speed: 1-2 Meter/ Minute
2.7.3 Warm-up temperature：100±20℃
2.7.4 Welding temperature：250±10℃
2.7.5 1 time pass wave crest welding machine
If disobey the above using terms, sensors sensitivity will be reduced.
合計 : 3 ページ
[ MQ136 データシート.PDF ]
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