The working principle of carbon dioxide alarm
Carbon dioxide alarm has a wide range of applications in many fields such as industry, agriculture, and environmental protection.
Let me introduce to you the working principle of carbon dioxide alarm.
Any substance has its characteristic brightline spectrum. Correspondingly there will be absorption spectra. The same goes for carbon dioxide gas molecules. The vibration of the crystal lattice of the ceramic material hinders the movement of electrons. As the temperature rises, the lattice vibration strengthens. The increase in the amplitude hinders the enhancement of the electronic function. According to the theory of selective gas absorption. When the emission wavelength of the light source matches the absorption wavelength of the gas, resonant absorption occurs. The absorption intensity is related to the concentration of the gas. The concentration of gas can be measured by measuring the absorption intensity of light.
At present, there are many types of carbon dioxide sensors. According to its principle, it can be divided into thermal conductivity type, density meter type, radiation absorption type, and electrical conductivity type. Chemical absorption, electrochemical, and chromatographic. Mass spectrometry, infrared optics, etc.
Infrared absorption carbon dioxide gas sensor
It is made based on the principle that the absorption spectrum of a gas varies with different substances. The carbon dioxide sensor element controls the internal infrared lamp to emit infrared light of a fixed band through the drive circuit. After being absorbed by the gas to be measured, the infrared light amplitude changes. Then calculate the concentration of the gas to be measured by detecting the amount of change. That is, the signals output by the sensor elements are filtered respectively. Amplification processing and ADC acquisition and conversion. Input to the microprocessor. The microprocessor system performs corresponding temperature according to the collected temperature and pressure. The pressure compensation process finally calculates the concentration of carbon dioxide to be measured and outputs it to the display device. There are mainly tunable diode laser absorption spectra. Photoacoustic spectroscopy technology, cavity enhanced spectroscopy technology and non-dispersive infrared spectroscopy technology, etc. There are many advantages of infrared absorption sensors. High sensitivity, fast analysis speed, good stability, etc.
Electrochemical carbon dioxide gas sensor
It is a type of chemical sensor that converts the concentration or partial pressure of carbon dioxide into an electrical signal through an electrochemical reaction. According to the detected electrical signals. The electrochemical type is divided into potential type, current type and capacitive type. According to the electrolyte form, there are liquid electrolytes and solid electrolytes. Since the 1970s until now. The solid electrolyte carbon dioxide sensor has always received the attention of the majority of scientific researchers. The principle of the solid electrolyte carbon dioxide sensor is that the gas-sensitive material generates ions when passing through the gas. Thereby, an electromotive force is formed, and the electromotive force is measured to measure the gas volume fraction.
Utilizes the difference in thermal conductivity between carbon dioxide and other gases. To make a thermal conductivity carbon dioxide gas sensor. It is also the earliest sensor used to detect carbon dioxide. But its sensitivity is low.