Sensor Types And Applications

Sensors can be categorized from different perspectives: their conversion principles (basic physical or chemical effects of sensor operation); their use; their output signal types and the materials and processes used to make them.
According to the working principle of the sensor, it can be divided into two categories: physical sensor and chemical sensor:

Classification of sensor operating principles Physical sensors use physical effects such as piezoelectric effects, magnetostriction, ionization, polarization, thermoelectric, optoelectronic, magnetoelectric and other effects. Minor changes in the measured semaphore will be converted into electrical signals.

Chemical sensors include those that cause causal relationships such as chemisorption and electrochemical reactions. Small changes in the measured signal volume are also converted into electrical signals.
Some sensors can neither be classified into physical classes nor classified as chemical. Most sensors operate on the basis of physical principles. There are many technical problems in chemical sensors, such as reliability issues, the possibility of mass production, and price issues. These problems have been solved, and the application of chemical sensors will grow tremendously.

The application areas and working principles of common sensors are listed in Table 1.1.

Sensors can be classified according to their use:

Pressure sensitive and force sensitive sensor position sensor

Level sensor energy sensor

Speed sensor thermal sensor

Acceleration sensor

Vibration sensor humidity sensor

Magnetic sensor

Vacuum sensor Biosensor, etc.

The sensor can be divided into:

Analog Sensor - Converts the measured non-electrical quantities into analog electrical signals.

Digital Sensor - Converts the measured non-electrical quantities into digital output signals (both direct and indirect).

膺 Digital Sensor - Converts the measured semaphore into the output of a frequency signal or short-cycle signal (including direct or indirect conversion).

Switch Sensor - When a measured signal reaches a certain threshold, the sensor outputs a set low or high signal accordingly.
 
Under the influence of external factors, all materials will have a corresponding and characteristic response. The materials that are most sensitive to external influences, that is, those with functional properties, are used to make sensitive components of the sensor. Sensors can be divided into the following categories from the point of view of the applied materials:


(1) according to the type of materials used

Metal polymer ceramic mixture

(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 amorphous material

Sensor development work closely related to the adoption of new materials can be summarized into the following three directions:

(1) Explore new phenomena, effects, and reactions in known materials and then make them practical for use in sensor technology.

(2) Explore new materials and apply known phenomena, effects, and reactions to improve sensor technology.

(3) Explore new phenomena, new effects and reactions on the basis of researching new materials, and implement them in sensor technology.
Advances in modern sensor manufacturing depend on the development of new materials and sensitive components for sensor technology. The basic trend in sensor development is closely related to the application of semiconductors and dielectric materials. Some of the materials that can be used in sensor technology to convert energy forms are given in Table 1.2.


According to its manufacturing process, the sensor can be divided into:

Integrated sensor film sensor thick film sensor ceramic sensor
Integrated sensors are fabricated using standard process technology for the production of silicon-based semiconductor integrated circuits. Part of the circuitry used to initially process the signal under test is also typically integrated on the same chip.
The thin film sensor is formed by a film of a corresponding sensitive material deposited on a dielectric substrate (substrate). When a mixing process is used, part of the circuit can also be fabricated on this substrate.
The thick film sensor is made by coating a slurry of a corresponding material on a ceramic substrate, which is usually made of Al2O3, and then heat-treated to form a thick film.
Ceramic sensors are produced using standard ceramic processes or some variation thereof (sol-gel, etc.).
After the appropriate preparatory operation is completed, the formed component is sintered at a high temperature. There are many common characteristics between the two processes of thick film and ceramic sensors. In some respects, the thick film process can be considered as a variant of the ceramic process.
Each process technology has its own advantages and disadvantages. Ceramic and thick film sensors are more reasonable due to lower capital investment required for research, development and production, and high stability of sensor parameters.

 

Speed sensor ---- is a rotary encoder that converts the speed into a pulse wave (5VDC) and sends it to the PLC or other processor for processing.
Current sensor ---- is a current transmitter that converts a current signal of 0-5A or greater into a standard control signal of 4-20mA or 0-20mA to the processor.
Voltage sensor---- is a voltage transmitter that converts a voltage signal of 0-100V or more into a standard control signal of 0-10V to the processor.
Vibration sensor----Detect vibration of mechanical equipment, perform linear output or relay output.
Hall sensor ---- is the inductive proximity switch, using the Hall principle. The detection distance will not exceed 10mm. The output signals are generally DC three-wire PNP or NPN outputs.
Cylinder pressure sensor - is a pressure sensor that can output a relay signal or a linear signal.
Air flow sensor - can output relay signal or linear signal of voltage and current.
Oxygen Sensor --
Throttle position sensor
Temperature sensor - This is generally a linear voltage output. And to use with the thermostat.