The gas sensor refers to the physical or chemical change produced by the physical or chemical reaction between the detected gas molecules and the gas-sensitive material. Converted into electrical signals, optical signals, acoustic signals, etc. that can be to effectively measure. Thus, a sensor for measuring gas species and concentration is to realize.
Working principle
According to the working principle, gas sensors can be divided into electrical gas sensors that directly measure the electrical properties of sensitive materials. and optical gas sensors that indirectly measure the type and concentration of gases.
Electrical gas sensors include semiconductor type, electrochemical type, catalytic combustion type, quartz microbalance type and surface acoustic wave type. Each principle is different. For example, the semiconductor type gas sensor mainly reacts with the gas based on the semiconductor sensitive material. Causes the gain and loss of electrons in sensitive materials. Thereby changing the electrical properties of the gas-sensing material. Gas can be accurately detected by detecting changes in its electrical properties.
Indirect measurement type gas sensor
The most important infrared gas sensor of indirect measurement type gas sensor is a kind of selective absorption characteristics based on the near-infrared spectrum of different gas molecules. A gas sensing device that uses the relationship between gas concentration and absorption intensity to detect gas components and determine their concentration.
With the continuous development of science and technology, gas sensors have been to widely use in the fields of security and environmental monitoring. In the field of security, there are miner’s lamp gas alarms mounted on miners’ caps. This miner’s lamp gas alarm has both lighting and gas alarm functions. Mainly suitable for small coal mines and family use. When a gas-sensitive resistor and a potentiometer form a gas detection circuit. The time base circuit and its peripheral components form a multivibrator.
Resistivity of the gas-sensitive
When there is no gas, the resistivity of the gas-sensitive resistor is very small and the resistance value is very large. The output voltage of the potentiometer sliding contact is small. The integrated circuit is forcibly reset the oscillator and does not work. The alarm does not alarm either. The conductivity increases rapidly when there is gas in the surrounding air. The resistance value becomes extremely small.
The voltage at the output of the sliding contact rises. When the integrated circuit becomes high, the start-up loudspeaker of the oscillator circuit emits an alarm sound. There are corresponding automatic air purifiers in the field of environmental monitoring, when the indoor air is to pollute or the harmful gas reaches a certain concentration. The automatic air freshener automatically generates negative oxygen ions to keep the air fresh.
In addition, gas sensors are to widely use in production process monitoring, gas composition analysis and other fields. It has provided strong support for the development of various industries in my country and the Internet of Everything.
Weihai Jingxun Changtong Electronic Technology Co., Ltd. was to establish in 2015, located in the most liveable city of Weihai. The company mainly provides sensing equipment and solutions in three areas of atmospheric environment monitoring, agricultural parameter monitoring and industrial gas detection. It is a full-line IoT product supplier integrating R&D, production and sales.
The company has a variety of sensors such as Portable gas detectors, Fixed gas analyzers, and Agricultural sensors.
And We can customize the products that best meet your requirements according to your needs.
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