subject: Gas Sensor Selection And Classification Of The Depth Of Analysis [print this page] Gas sensor The core of a gas detection system, usually installed in the probe within. In essence, the gas sensor is the volume fraction of gas converted into a corresponding electrical signal converter. Probe of gas through the gas sample conditioning sensors, usually filter out impurities and disturbances, including gas, drying or cooling treatment, the sample pump, and even chemical treatment of samples for chemical sensor measurements more rapidly.
Gas sampling directly affect the sensor's response time. At present, the gas sample is mainly by simple diffusion, or inhalation of the gas detector.
According to measurement and measurement of environmental objects to determine the type of sensors. To carry out? A specific survey work, we must first consider what principles of sensors, which, after a number of factors need to be analyzed can be determined. Because, even measuring the same physical quantity, there are a variety of sensors for use principle, which principle is more appropriate sensors will need to be measured according to the characteristics and conditions of use sensors to consider the following specific issues: the size range; location of the sensor measured the volume of requests; measurement for the contact or non-contact; signal extraction method, cable, or non-contact measurement; sensor sources, domestic and imported, the price could suffer, or self-developed. After considering the above issues will determine what type of sensor used, and then consider the specific sensor performance.
Sensitivity options are usually in linear range of the sensor in the hope that the higher the better sensitivity of the sensor. Because only high sensitivity, and changes are measured values of the corresponding output signal is rather large, favorable signal processing. But note that the sensor has high sensitivity and independent of external noise is measured easily mixed, the system will be enlarged to enlarge, impact measurement accuracy. Therefore, the required sensor itself should have a higher signal to noise ratio, to minimize the introduction of the interference from outside signals. Sensitivity of the sensor is directional. When measurement is one-way traffic, and its direction are higher, and should choose the direction of the sensitivity of other small sensor; if the measure is multi-dimensional vector, requires cross-sensitivity of the sensor as small as possible.
Response characteristics (response time). Frequency response of the sensor determines the frequency range being measured, the frequency range must be allowed to remain undistorted measurement conditions, in fact, the total sensor response? Be delayed, to delay time as short as possible. High frequency response sensors, the signal can be measured on the wide frequency range, but due to structural characteristics, mechanical inertia larger, due to the low frequency sensor signals can be measured less frequently. In dynamic measurement, should be based on the characteristics of the signal (steady state, transient, random, etc.) response to avoid excessive errors.
Linear range. The linear range is proportional to the output and input range. In theory, in this context, to maintain constant sensitivity. Wider linear range of the sensor, its greater range and can guarantee accuracy. In the choice of sensors, when the type of sensor to determine whether the future depends on their range to meet the requirements. In practice, any sensor can not guarantee absolute linear, its linearity and relative. When the required accuracy is relatively low, in a certain range, can be non-linear error is small as a linear approximation of sensors, which measure will bring great convenience
Gas sensor is a chemical sensor of a door to class. From the working principles, characteristics of the measurement techniques, from the material to the manufacturing process, from the detection object to applications, can constitute a separate classification criteria led to a months numerous numerous and the classification system, especially in the classification standard issue now not uniform, to its strict taxonomy considerable difficulty.
Gas sensing properties are usually classified, can be divided into: Semiconductor Gas sensors, electrochemical gas sensors, solid electrolyte gas sensors, contact sensors, burning gas.
Semiconductor gas sensors
Semiconductor gas sensor is a metal oxide or metal oxide materials made of semiconductor components, and gas adsorption interaction or reaction arising caused to the carrier movement is characterized by the conductivity or voltage characteristics, or surface potential changes.
Gas Sensor Selection And Classification Of The Depth Of Analysis
