Classification of sensors
Classification of sensors
The sensor is a device designed according to the physical, chemical, biological characteristics and laws of materials. In the field of measurement and control, sensors designed by certain principles can measure various non-electrical quantities at the same time. Sometimes a non-electric sensor can be measured by sensors with different principles. Therefore, there are many classification methods for sensors. Generally, they can be classified according to the following methods.
1. Classified by input
According to the input, the sensor can be divided into pressure, displacement, speed, temperature, humidity, etc. This classification method clearly expresses the purpose of the sensor and is easy to select, but it is difficult to find the commonalities and differences of the conversion principles of each sensor by classifying sensors with different principles into one category.
2. Classified by measurement principle
This classification method is based on the principles, laws and influences of physical chemistry, such as voltage, thermoelectricity, resistance, photoelectricity, and inductance. The advantage of this classification method is that the working principle of the sensor is clear and the classification is less, which is conducive to the in-depth analysis and research of the sensor.
3. Classified by energy relationship
From the energy point of view, sensors can be divided into active sensors and passive sensors. The former converts non-electric energy into electric energy, called energy conversion sensor. Usually with voltage measuring circuit and amplifier, such as piezoelectric, pyroelectric, electromagnetic, etc. Passive sensors are also called energy control sensors. It is not a sensor in itself. The measured non-electricity only controls or regulates the energy in the sensor. Therefore, they must have auxiliary power supplies. Such sensors have resistive, capacitive, and inductive types.
4. Semiconductor theoretical classification
Divided into solid-state sensors such as semiconductor force sensitive, thermal, photoperiod, and gas sensitive.
5. Classification by output
According to the output, there are analog and digital sensors. The output signal of the analog sensor is an analog signal, and the output signal of the digital sensor is a digital signal, which is easy to use by a computer and has strong anti-interference ability, such as disc angle pressure digital sensor, grating sensor, etc.
6. Other categories
Sensors can also be classified according to their structure and physical characteristics.
(1) Structural type
Mainly by changing the geometric shape or size of the mechanical structure, the external measurement is converted into corresponding changes in physical quantities such as resistance, inductance, and capacitance, so as to detect the measured signal. Sensors are currently the most widely used.
(2) Physical property type
Physical type is measured by changes in the physical properties of certain materials. It is a solid-state device containing sensitive materials such as semiconductors, dielectrics, and ferroelectrics.