Classification of sensors
From different angles, different sensor classification methods are formed. A measured sensor can be measured with different types of sensors, and the same principle of the sensor can usually measure a variety of measured, therefore, the classification of sensors are different, there is no unified classification method.
1. Classification according to the working mechanism of the sensor
According to the scientific properties of the basic effects on which the perception is measured (external information), sensors can be divided into three categories: physical sensors, chemical sensors and biological sensors.
Physical sensor is a sensor that uses the physical properties of some components and the special physical properties of some functional materials, such as piezoelectric effect, magnetostriction phenomenon, ion, thermoelectric, photoelectric, magnetoelectric and other effects to convert the measured physical quantity into a signal in the form of energy that is easy to handle. Small changes in the measured signal are converted into electrical signals, where electrons conduct electricity, which is relatively easy to develop later.
In the physical sensor can be divided into physical property sensor and structural sensor. The structural sensor is based on the laws of the physics field, including the law of motion of the dynamic field and the electromagnetic law of the electromagnetic field. The characteristic of this type of sensor is that the working principle of the sensor is based on the change of the field caused by the change of the relative position of the component in the sensor, rather than on the change of the material characteristics. For example, the capacitive sensor is a structural sensor made of electrostatic field law, and the variation of the shape and distance of the plate can change the performance of the capacitive sensor. Physical sensors are based on the laws of matter, such as Hooke's law, Ohm's law and so on. A law of matter is a law that expresses some objective property of matter. Most of these rules are given in the form of constants of the substance itself, and the size of these constants determines the main performance of the sensor. Therefore, the performance of the physical sensor varies with the material. For example, the piezoelectric sensor is a physical property sensor made of the piezoelectric effect of materials, and the piezoelectric effect is different for different piezoelectric materials.
Chemical sensors mainly use the principle of electrochemical reaction between sensitive materials and substances to convert the concentration of inorganic and organic chemical components into electrical signals, such as gas sensors, humidity sensors and ion sensors, in which ions play a conductive role. There are many types of ions, so the chemical sensor changes a lot, is more complex, relatively difficult to develop later.
Biosensors are sensors that use bioactive substances, such as molecules, cells and even some biological body tissues, to select the characteristics of certain substances, such as glucose sensors formed by the combination of glucose and microelectrodes, enzyme sensors, microbial sensors, tissue sensors and immune sensors. The research history of biosensors is short, but the development is very rapid, with the development of semiconductor technology, microelectronics technology and biotechnology, its performance will be further improved, multi-functional, integrated and intelligent biosensors will become a reality, the prospect is very broad.
2. Classify the sensor according to the working principle
According to the principle of the sensor's effect on signal conversion, it can be divided into resistive sensors, inductive sensors, capacitive sensors, piezoelectric sensors, magnetoelectric sensors, photoelectric sensors, thermoelectric sensors, wave sensors, etc. Classification according to the working principle is conducive to understanding the working principle of the sensor.
3. Sort by input information (measured)
Sensors according to the amount of input (use) classification of displacement sensor, pressure sensor, position sensor, liquid level sensor energy consumption sensor, speed sensor, temperature sensor, vibration sensor, humidity sensor, magnetic sensor, gas sensor, vacuum sensor and so on. The method of classification according to the measurement reflects the function and use of the sensor, which is conducive to the user's targeted selection of the sensor. In many cases, the two methods of classification according to the working principle and classification according to the measurement are often integrated, such as strain gauge pressure sensors, piezoelectric acceleration sensors, optical code disk speed sensors, etc.
4. Categorize by application scope
According to the different application scope of the sensor, it is usually divided into industrial, civil, scientific research, medical, military sensors and so on. According to the specific use occasion, it can also be divided into automotive, naval, aerospace sensors and so on. If according to the purpose of use, it can also be divided into measurement, monitoring, inspection, control, analysis and other sensors.
