The classification of the sensor has a lot of, also sensors can be classified in different ways. There is a certain type of from the purpose to distinguish sensor measurement. This sensor type can be divided into physical sensors, chemical sensors, etc. Here are physical type sensor to introduce a simple analysis, physical type sensor and can be divided into structural and property type sensor.
Structured sensor based on structure (such as shape, size, etc.) as the foundation, using some of the laws of physics to feel (sensitive) is measured, convert them into electrical signals to realize measurement. Capacitive pressure sensor, for example, must be in accordance with the provisions, parameter design of capacitive sensing element, when the measured pressure effect on the dynamic plate of capacitive sensing element, cause the change of capacitance gap leads to the change of capacitance value, so as to realize the pressure measurement. Such as resonant pressure sensor again, must design a suitable pressure measured resonant sensor, when measured pressure change, change the resonant sensitive equivalent stiffness of the structure, lead to changes in the natural frequencies of the resonant sensor, so as to realize the pressure measurement.
Property type sensor is to use some function of material itself have intrinsic characteristics and effect feeling (sensitive) is measured, translates into usable electrical signal sensor. For example using quartz crystal materials with piezoelectric properties of piezoelectric sensor, is using the positive piezoelectric effect of quartz crystal material itself has to achieve to pressure measurement; Use of semiconductor materials in the measured pressure under the action of its internal stress changes in the electrical resistance change made of piezoresistive sensor, is using the piezoresistive effect of semiconductor materials and implementation of pressure measurement.
In general, the physical structure of the sensor is sensitive to physical effect and has certain requirements, but with different emphasis. Structured will rely on precision design the structure of the sensor emphasized to ensure the normal work; And property type sensor is mainly on the basis of physical properties of the material itself, physical effect to realize induction to be measured. In recent years, due to the rapid development of materials science and technology and progress, physical type sensor is applied more and more widely. This and this kind of sensor is easy to mass production, low cost, easy to miniaturization is closely related to the holding point, etc.
