What Are The Types Of Common Sensors?

A sensor is a component that uses new high-tech technology to measure physical and chemical effects. It is often used to detect and respond to electronic or optical signals, so there are many varieties. The following is a detailed introduction to the types of sensors:

1. Resistive sensor

• A resistive sensor is a device that converts the measured physical quantities, such as displacement, deformation, force, acceleration, humidity, temperature, etc., into resistance values. There are mainly resistive sensing devices such as resistance strain type, piezoresistive type, thermal resistance, heat-sensitive, gas-sensitive, and humidity-sensitive.

 

 

2. Temperature sensor

• The temperature sensor is mainly based on the principle that the resistance value of the resistance and the potential of the thermocouple change regularly with different temperatures, and we can obtain the temperature value that needs to be measured. There are not only a wide variety of temperature sensors, but also various combinations. Appropriate products should be selected according to different places.

3. Pressure sensor

• The pressure sensor is the most commonly used sensor in industrial practice. It is widely used in various industrial automatic control environments, involving water conservancy and hydropower, railway transportation, intelligent buildings, production automatic control, aerospace, military industry, petrochemical, oil wells, electric power, ships, Machine tools, pipelines, and many other industries.

4. Frequency conversion power sensor

• The frequency conversion power sensor performs AC sampling on the input voltage and current signals, and then connects the sampled values to the secondary instrument with digital input through transmission systems such as cables and optical fibers, and the secondary instrument with digital input performs calculations on the sampled values of voltage and current, you can get voltage RMS value, current RMS value, fundamental voltage, fundamental current, harmonic voltage, harmonic current, active power, fundamental power, harmonic power and other parameters.

5. Resistive strain sensor

• The resistance strain gauge in the sensor has the strain effect of metal, that is, mechanical deformation occurs under the action of external force, so the resistance value changes accordingly. There are two types of resistance strain gauges: metal and semiconductor. Metal strain gauges can be divided into wire type, foil type and film type. Semiconductor strain gauges have the advantages of high sensitivity (usually dozens of times that of wire and foil types) and small lateral effects.

6. Thermal resistance sensor

• Thermal resistance temperature measurement is based on the characteristic that the resistance value of metal conductors increases with the increase of temperature to measure temperature. Most thermal resistances are made of pure metal materials, and platinum and copper are the most widely used at present. In addition, materials such as nickel, manganese, and rhodium have been used to manufacture thermal resistances. It mainly uses the characteristic that the resistance value changes with temperature to measure temperature and temperature-related parameters. This sensor is more suitable for occasions where the temperature detection accuracy is relatively high.

 

 

7. Laser sensor

• Sensors that make measurements using laser technology. It consists of a laser, a laser detector, and a measurement circuit. The laser sensor is a new type of measuring instrument. Its advantages are that it can realize non-contact long-distance measurement, fast speed, high precision, large measuring range, and strong ability to resist the light and electrical interference. When the laser sensor is working, the laser emitting diode is aimed at the target to emit laser pulses. After being reflected by the target, the laser light is scattered in all directions, and part of the scattered light returns to the sensor receiver. After being received by the optical system, it is imaged on the avalanche photodiode.

8. Hall sensor

• The Hall sensor is a magnetic field sensor made according to the Hall effect, which is widely used in industrial automation technology, detection technology, and information processing. The Hall effect is a basic method for studying the properties of semiconductor materials. The Hall coefficient measured by the Hall effect experiment can determine important parameters such as the conductivity type, carrier concentration, and carrier mobility of semiconductor materials.

9. Wireless temperature sensor

• The wireless temperature sensor converts the temperature parameters of the control object into electrical signals and sends wireless signals to the receiving terminal to detect, adjust, and control the system. It can be directly installed in the junction box of general industrial thermal resistance and thermocouple and forms an integrated structure with field sensing elements. It is usually used in conjunction with wireless relays, receiving terminals, communication serial ports, electronic computers, etc. This not only saves compensation wires and cables but also reduces signal transmission distortion and interference, thus obtaining high-precision measurement results.

10. Smart sensors

• The function of the smart sensor is proposed by simulating the coordinated action of the human senses and brain, combined with long-term research and practical experience in testing technology. It is a relatively independent intelligent unit. Its appearance has alleviated the harsh requirements of the original hardware performance, and the performance of the sensor can be greatly improved with the help of software.

11. Vision sensor

• A visual sensor refers to the ability to capture thousands of pixels of light from an entire image. The clarity and fineness of an image are often measured by resolution, expressed in terms of the number of pixels. Vision sensors have thousands of pixels that capture light from an entire image. The sharpness and detail of an image is usually measured by resolution, expressed in the number of pixels.

12. Displacement sensor

• A displacement sensor is also called a linear sensor, a sensor that converts displacement into electricity. The displacement sensor is a linear device that belongs to metal induction. The function of the sensor is to convert various measured physical quantities into electricity. It is divided into inductive displacement sensors, capacitive displacement sensors, photoelectric displacement sensors, ultrasonic displacement sensors, Hall Hall-type displacement sensors.

13. Grating sensor

• Metrological gratings are usually used in digital detection systems to detect high-precision linear displacement and angular displacement. It is a detection device that is widely used on CNC machine tools. The spatial resolution of the grating sensor can generally reach about 1 μm, the length of a single grating can reach more than 600 mm, the main grating can be spliced, and the measurement range can reach more than several meters.

14. Vacuum sensor

• The vacuum sensor is produced by advanced silicon micro-machining technology. It is an absolute pressure transmitter made of integrated silicon piezoresistive element as the core element of the sensor. Due to the use of silicon-silicon direct bonding or silicon-Pyrex glass electrostatic The vacuum reference pressure cavity formed by bonding, and a series of stress-free packaging technology and precision temperature compensation technology have outstanding advantages of excellent stability and high precision and are suitable for the measurement and control of absolute pressure in various situations.

15. Ultrasonic distance sensor

• The ultrasonic distance measuring sensor adopts the principle of ultrasonic echo ranging and uses accurate time difference measurement technology to detect the distance between the sensor and the target. It adopts a small angle, small blind area ultrasonic sensor, which has the advantages of accurate measurement, non-contact, waterproof, anti-corrosion, and low cost. Other advantages, it can be applied to liquid level and material level detection. The unique liquid level and material level detection method can ensure stable output when there is foam or large shaking on the liquid surface and it is difficult to detect the echo.

16. Load cell

• A load cell is a force-to-electricity conversion device that can convert gravity into an electrical signal and is a key component of an electronic weighing instrument. There are many kinds of sensors that can realize force-to-electricity conversion, and the common ones are resistance strain type, electromagnetic force type, and capacitive type. The electromagnetic force type is mainly used for electronic balances, the capacitive type is used for some electronic crane scales, and the vast majority of weighing instruments use resistance strain-type load cells. The resistance strain type load cell has a simple structure, high accuracy, and wide applicability, and can be used in a relatively poor environment.

 

 

17. Capacitive level sensor

• The capacitive level sensor is composed of a capacitive sensor and an electronic module circuit. It is based on a two-wire 4~20mA constant current output. After conversion, it can be output in a three-wire or four-wire mode. The output signal is formed as 1~5V, 0~5V, 0~10mA, and other standard signals. Capacitive sensors consist of insulated electrodes and a cylindrical metal container containing the measuring medium. When the material level rises, because the dielectric constant of the non-conductive material is significantly smaller than that of air, the capacitance changes with the height of the material.

18. Antimony electrode acidity sensor

• The antimony electrode acidity sensor is an industrial online analysis instrument integrating pH detection, automatic cleaning, and electrical signal conversion. It is a pH value measurement system composed of an antimony electrode and a reference electrode. In the acid solution to be tested, since the antimony trioxide oxide layer is formed on the surface of the antimony electrode, a potential difference will be formed between the metal antimony surface and the antimony trioxide. The magnitude of this potential difference depends on the concentration of the three antimony oxides, which correspond to the appropriateness of hydrogen ions in the acidic solution to be measured.

19. Piezoresistive sensor

• The piezoresistive sensor is a device made by spreading resistance on the substrate of the semiconductor material according to the piezoresistive effect of the semiconductor material. The substrate can be directly used as a measuring sensor element, and the diffusion resistance is connected to the substrate to form a bridge. When the substrate is deformed by an external force, the resistance values will change, and the bridge will produce a corresponding unbalanced output. The substrate (or diaphragm) materials used as piezoresistive sensors are mainly silicon wafers and germanium wafers. Silicon piezoresistive sensors made of silicon wafers as sensitive materials have attracted more and more attention, especially for measuring pressure. Solid-state piezoresistive sensors for speed and speed are most commonly used.

20. Photosensitive sensor

• The photosensitive sensor is one of the most common sensors. It has a wide variety, mainly including: photocells, photomultiplier tubes, photoresistors, phototransistors, solar cells, infrared sensors, ultraviolet sensors, fiber optic photoelectric sensors, color sensors, CCD and CMOS image sensors, etc. Its sensitive wavelengths are around the wavelengths of visible light, including infrared and ultraviolet wavelengths. The light sensor is not limited to the detection of light, it can also be used as a detection element to form other sensors to detect many non-electric quantities, as long as these non-electric quantities are converted into changes in optical signals. The optical sensor is currently one of the sensors with the largest output and widest application, and it occupies a very important position in the introduction of automatic control and non-electrical measurement technology.

21. Infrared sensor

• The infrared sensor is a sensor that uses the principle of a thermocouple to detect infrared radiation from the physical effect of the interaction between infrared radiation and matter. In most cases, it uses the electrical effect of this interaction. Measure the difference between the target object and the sensor or the object and the ambient temperature. The principle of the thermocouple is that two different metals A and B form a closed loop. When the temperature of the two contact ends is different (T>To), thermoelectricity is generated in the loop. Potential Eab, where T is called the hot end, working end, or measuring end, and To is called the cold end, free end, or reference end. A and B are called thermoses. The size of the thermoelectric potential is determined by the contact potential (also called the Burr paste potential) and the temperature difference potential (also called the Thomson potential).

 

 

22. Conductivity sensor

• It is a process instrument (integrated sensor) that indirectly measures ion concentration by measuring the conductivity value of the solution, and can continuously detect the conductivity of aqueous solution in the industrial process online. Since the electrolyte solution is a good conductor of electricity like a metal conductor, there must be resistance when the current flows through the electrolyte solution, and it conforms to Ohm's law. However, the resistance temperature characteristics of liquids are opposite to those of metal conductors and have negative temperature characteristics. In order to distinguish it from metal conductors, the conductivity of the electrolyte solution is expressed by conductance (reciprocal of resistance) or conductivity (reciprocal of resistivity). When two electrodes insulated from each other form a conductivity cell, if the solution to be tested is placed in the middle, and a constant voltage alternating current is passed through, a current loop is formed. If the voltage and electrode size is fixed, there is a certain functional relationship between the loop current and the conductivity.