Professional Knowledge

The main classification of sensors

A sensor is a detection device that can feel the information being measured, and can transform the sensed information into electrical signals or other required forms of information output according to a certain rule, so as to satisfy the transmission, processing, storage, and display of information , Recording and control requirements.
The main categories of sensors:
By purpose
Pressure sensitive and force sensitive sensors, position sensors, liquid level sensors, energy consumption sensors, speed sensors, acceleration sensors, radiation sensors, thermal sensors.
According to the principle
Vibration sensor, humidity sensor, magnetic sensor, gas sensor, vacuum sensor, biological sensor, etc.
Press output signal
Analog sensor: Convert the measured non-electrical quantity into an analog electric signal.
Digital sensor: Convert the measured non-electrical quantity into a digital output signal (including direct and indirect conversion).
Fake digital sensor: Convert the measured signal into a frequency signal or short-period signal output (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.
By manufacturing process
The integrated sensor is manufactured using standard process technology for the production of silicon-based semiconductor integrated circuits.
Usually part of the circuit used for preliminary processing of the signal under test is also integrated on the same chip.
The thin-film sensor is formed by a thin film of the corresponding sensitive material deposited on the dielectric substrate (substrate). When using a hybrid process, part of the circuit can also be manufactured on this substrate.
The thick film sensor is made by coating the slurry of the corresponding material on a ceramic substrate, which is usually made of Al2O3, and then undergoes heat treatment to form the thick film.
Ceramic sensors are produced using standard ceramic processes or some variant processes (sol, gel, etc.).
After completing the appropriate preparatory operations, the formed components are sintered at high temperatures. There are many common features between the thick film and ceramic sensor processes. In some respects, the thick film process can be considered a variation of the ceramic process.
Each process technology has its own advantages and disadvantages. Due to the low capital investment required for research, development, and production, as well as the high stability of sensor parameters, it is more reasonable to use ceramic and thick film sensors.
According to the measurement item
Physical sensors are made using the obvious changes in certain physical properties of the measured substance.
Chemical sensors are made of sensitive elements that can convert chemical quantities such as the composition and concentration of chemical substances into electrical quantities.
Biosensors are sensors that are made using the characteristics of various organisms or biological substances to detect and identify chemical components in organisms.
According to its composition
Basic sensor: It is the most basic single conversion device.
Combined sensor: It is a sensor composed of a combination of different single transforming devices.
Application sensor: It is a sensor composed of a basic sensor or a combination sensor and other mechanisms.
According to the form of action
According to the form of action, it can be divided into active and passive sensors.
Active sensors also have action type and reaction type. This type of sensor can send a certain detection signal to the measured object, and can detect the change of the detection signal in the measured object, or the detection signal produces some kind of detection in the measured object. Effect and form a signal. The method that detects the change of the detection signal is called the action type, and the method that detects the response to form a signal is called the reaction type. Radar and radio frequency range detectors are examples of the action type, while photoacoustic effect analysis devices and laser analyzers are examples of the reaction type.
Passive sensors only receive signals generated by the object to be measured, such as infrared radiation thermometers, infrared camera devices, etc.