Classification of sensors

A sensor is a detection device that can feel the information to be measured, and can transform the detected and felt information into electrical signals or other required forms of information output according to certain rules to meet the needs of information transmission, processing, storage, and Display, record and control requirements. It is the first link to realize automatic detection and automatic control. The Chinese standard GB7665-87 defines a sensor as: "A device or device that can sense the specified measurement and convert it into a usable signal according to a certain rule, usually composed of sensitive components and conversion components."

Sensors can be classified from different perspectives: their conversion principles (the basic physical or chemical effects of sensor work); their purpose; their output signal types and the materials and processes used to make them.

According to the working principle of sensors, sensors can be classified into two categories: physical sensors and chemical sensors:

Classification of sensor working principle Physical sensors apply physical effects, such as piezoelectric effect, magnetostriction, ionization, polarization, pyroelectric, photoelectric, magnetoelectric and other effects. Small changes in the measured signal volume will be converted into electrical signals.

Chemical sensors include those that take chemical adsorption, electrochemical reactions and other phenomena as causal relationships. Small changes in the measured signal will also be converted into electrical signals.

Some sensors can neither be classified into physical or chemical categories. Most sensors operate on the basis of physical principles. There are many technical problems with chemical sensors, such as reliability issues, the possibility of mass production, price issues, etc. If such problems are solved, the application of chemical sensors will have a huge growth.

Sensor classification

Sensor classification 1: According to its purpose, sensors can be classified

Pressure sensitive and force sensitive sensors Position sensor Angle sensor Liquid level sensor 

Energy sensor

Speed

​​sensor Acceleration sensor 

Ray radiation sensor thermal sensor

Sensor classification 2: According to its principle, sensors can be classified

Vibration sensor

 Humidity sensor

Magnetic sensor

 Gas sensor

Vacuum sensor

 biological sensor, etc. 

Sensor classification 3: Based on its output signal, the sensor can be divided into:

Analog sensor-convert the measured non-electrical quantity into an analog electric signal. 

Digital sensor-convert the measured non-electric quantity into digital output signal (including direct and indirect conversion).

 Fake digital sensor-the output that converts the measured signal amount into a frequency signal or short-period signal (including direct or indirect conversion).

 Switch sensor-when a measured signal reaches a certain threshold, the sensor correspondingly outputs a set low or high level signal.

Sensor classification 4: According to material classification

　 Under the influence of external factors, all materials will make corresponding and characteristic responses. Among them, those materials that are most sensitive to external effects, that is, materials with functional characteristics, are used to make the sensor's sensitive components. From the point of view of applied materials, sensors can be divided into the following categories:

(1) According to the types of materials used: metals, polymers, ceramics, mixtures

(2) According to the physical properties of the material: conductor, insulator, semiconductor, magnetic material

(3) According to the crystal structure of the material: single crystal, polycrystalline, and amorphous materials

Sensor category 5: According to its manufacturing process, sensors can be divided into:

Integrated sensors, thin film sensors, thick film sensors, ceramic sensors