1.   Classification according to working principle

     According to the working principle, sensors can be divided into physical sensors and chemical sensors. Among them, physical sensors apply physical principles, such as piezoelectric effect, magnetostriction, thermoelectricity, photoelectricity, magnetoelectricity, ionization, polarization and so on. Chemical sensors are based on the principles of chemical adsorption and electrochemical reaction. Small changes in the measured signal will be converted into electrical signals. At present, most sensors operate on the basis of physical principles. With the development of technology and the reduction of cost, chemical sensors will be more widely used.

      2.  Classification by use

      Sensors can be divided into pressure and force sensors, position sensors, liquid level sensors, energy consumption sensors, speed sensors, acceleration sensors, radiation sensors, humidity sensors, thermal sensors, magnetic sensors, gas sensors, vacuum sensors, biosensors, etc. At present, the common ones are thermal sensor, humidity sensor, magnetic sensor, gas sensor, speed sensor and so on.

      3.   Classification by constituent materials

      Sensors can be divided into metal sensors, polymer sensors, ceramic sensors and mixture sensors according to the types of constituent materials. Sensors can be divided into conductor sensors, insulator sensors, semiconductor sensors and magnetic material sensors according to the physical properties of materials. Sensors can be divided into single crystal sensors, polycrystalline sensors and amorphous material sensors according to the crystal structure of materials.

       4.   Classification by manufacturing process

Sensors can be divided into integrated sensors, thin film sensors, thick film sensors and ceramic sensors according to manufacturing process. The common sensors are integrated sensor, ceramic sensor and thick film sensor.