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The base is suitable for the full range of MQ sensors

MQ-131 ozone sensor and oxygen sensor module
Specific parameters:
Dimensions: 32mm X22mm X27mm (length X width X height)
Main chips: LM393, MQ-131 gas sensor
Working voltage: 5V DC
Features:
1. It is equipped with a signal output indicator light for indication.
2. Dual signal output (analog output and TTL level output);
3. The TTL output valid signal is at a low level. When the output level is low, the signal light is on and it can be connected to the IO port of a single-chip microcomputer.
4. The analog output increases with the increase of concentration, and the higher the concentration, the higher the voltage.
5. It has a very high sensitivity to ozone gas (detection concentration range: 10PPB-2PPM)
6. It has a long service life and reliable stability;
7. Fast response and recovery feature;
8. Equipped with installation holes for convenient fixed installation;
9. The probe is designed to be plug-and-pull, which is convenient for experiments.
Application:
Ozone gas detection devices for household and atmospheric environments
MQ-136 Hydrogen sulfide detection Sensor module
Product Introduction:
The analog output voltage is 0 to 5V. The higher the concentration, the higher the voltage.
It has good sensitivity to hydrogen sulfide, liquefied gas, natural gas, city gas and smoke.
It has a long service life and reliable stability
Fast response and recovery feature
Application:
Gas leakage monitoring devices suitable for households or factories, and applicable to monitoring devices for liquefied gas, butane, propane, methane, alcohol, hydrogen, smoke, etc.
Applicable occasions: Single-chip microcomputer learning, electronic competitions, product development, graduation design...
MQ137
Product features:
The gas-sensitive material used in the MQ137 gas sensor is tin dioxide (SnO2), which has a relatively low electrical conductivity in clean air. When ammonia gas is present in the environment where the sensor is located, the conductivity of the sensor increases with the increase of ammonia gas concentration in the air. The change in electrical conductivity can be converted into an output signal corresponding to the concentration of the gas using a simple circuit. The MQ137 gas sensor has a high sensitivity to ammonia and is also ideal for monitoring other organic amines such as trimethylamine and ethanolamine. This sensor can detect various ammonia-containing gases and is a low-cost sensor suitable for a wide range of applications.
MQ138
The formaldehyde gas sensor detection module outputs TTL level signals (which can be connected to the IO port of a single-chip microcomputer such as 51, etc.) and voltage analog signals. Additionally, the module can detect aldehydes, benzene, aromas, ketones, etc. The error and consistency of the detection data belong to the medium and low-end level. It is applied to qualitative judgment and non-affirmative quantitative detection. The cross-data interference caused by VOC and TVOC gases is relatively obvious.
Application:
Volatile substance detection devices for household and environmental use, suitable for the detection of aldehydes, alcohols, ketones, aromatic compounds, and concentration testing of gas-sensitive components
MQ139
A Freon gas detection device for household and environmental use, suitable for the detection of R11, R22, R113, R134, R409A, R410A, etc. The test concentration range of gas-sensitive components: R134A 10 to 1000pp
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