Pressure sensors are one of the most widely used sensors. Traditional pressure sensors are mainly mechanical structure devices, and the deformation of elastic elements indicates the pressure, but this structure is large in size and heavy in weight, and cannot provide electrical output. With the development of semiconductor technology, semiconductor pressure sensors have also come into being. It is characterized by small size, light weight, high accuracy and good temperature characteristics. In particular, with the development of MEMS technology, semiconductor sensors are developing towards miniaturization, and their power consumption is low and reliable.

　　Introduction to the working principle of several common pressure sensors:

　　1. Piezoresistive pressure sensor

　　Resistive strain gauges are one of the main components of piezoresistive strain transducers. The working principle of metal resistance strain gauge is the phenomenon that the resistance value changes due to mechanical deformation due to the strain resistance adsorbed on the base material, which is commonly known as the resistance strain effect.

　　2. Ceramic pressure sensor

　　The ceramic pressure sensor is based on the piezoresistive effect, the pressure directly acts on the front surface of the ceramic diaphragm, so that the diaphragm produces a slight deformation, the thick film resistor is printed on the back of the ceramic diaphragm, connected into a Wheatstone bridge, due to the piezoresistive effect of the varistor, the bridge produces a highly linear voltage signal proportional to the pressure, and the excitation voltage is also proportional, the standard signal is calibrated to 2.0/3.0/3.3mV/V according to the different pressure ranges, etc., which can be compatible with strain gauge sensors.

　　3. Diffusion silicon pressure sensor

　　The working principle of the diffusion silicon pressure sensor is also based on the piezoresistive effect, using the principle of piezoresistive effect, the pressure of the measured medium directly acts on the diaphragm of the sensor (stainless steel or ceramic), so that the diaphragm produces a micro-displacement proportional to the pressure of the medium, so that the resistance value of the sensor changes, the electronic circuit is used to detect this change, and converts and outputs a standard measurement signal corresponding to this pressure.

　　4. Sapphire pressure sensor

　　Using the strain resistance operating principle, silicon-sapphire is used as a semiconductor sensitive element with unmatched metering characteristics. Therefore, semiconductor sensitive components made of silicon-sapphire are not sensitive to temperature changes and have good working characteristics even under high temperature conditions. Sapphire has strong radiation resistance; In addition, silicon-sapphire semiconductor sensitive components have no p-n drift.

　　5. Piezoelectric pressure sensor

　　The piezoelectric effect is the main operating principle of piezoelectric sensors, which cannot be used for static measurements because the charge after the action of an external force is only saved if the loop has an infinite input impedance. This is not the case, so this dictates that piezoelectric sensors can only measure dynamic stresses.

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Pressure sensors, as pressure metering elements or sensitive elements, play a vital role in modern technology and industry. Its accuracy level is one of the important indicators to measure its performance.

　　1. Overview of accuracy grades

　　The accuracy class of a pressure sensor is usually divided according to its margin of error. The different accuracy classes represent the magnitude of the sensor’s error during the measurement process. Common accuracy classes include C3, C2, C1, G1, G2, G3, and G5. Among them, C3 has the highest accuracy, with an error range of ±0.020%, that is, an accuracy of 2/10,000; The G5 has the lowest accuracy, with an error range of ±0.5%, or 5 thousandths of an accuracy.

　　In addition, static accuracy and full-temperature range accuracy are two important indicators of the accuracy of a pressure sensor. Static accuracy refers to the accuracy that should be achieved at a particular temperature, while full-temperature range accuracy refers to the accuracy that the sensor should achieve over the entire temperature range in use.

　　2. Detailed explanation of accuracy level

　　C3 accuracy class: The error range is within ±0.020%, which is the highest accuracy among pressure sensors. It is suitable for occasions that require extremely high accuracy, such as high-precision measurement, scientific research and other fields.

　　C2 accuracy level: the error range is within ±0.030%, that is, 3/10,000 accuracy. Although the accuracy is slightly lower than C3, it is still sufficient in many industrial applications.

　　C1 accuracy level: the error range is within ±0.050%, that is, 5/10,000 accuracy. It is suitable for general industrial measurement and control occasions.

　　G1 accuracy level: the error range is within ±0.1%, that is, one thousandth of an accuracy. In some industrial areas where accuracy requirements are not particularly high, G1 precision pressure sensors are sufficient.

　　G2, G3 and G5 accuracy classes: the error range is within ±0.2%, ±0.3% and ±0.5% respectively. These pressure sensors are suitable for applications where low accuracy is required, such as general industrial monitoring and control.

　　2. Accuracy level and application scenarios

　　Choosing the appropriate accuracy class is critical for the application of a pressure sensor. High-precision pressure sensors can provide more accurate data, but correspondingly, they can also be more expensive. Therefore, when selecting a pressure sensor, it is necessary to weigh the relationship between accuracy and cost according to the needs of the actual application scenario.

　　In the aerospace sector, for example, the accuracy of pressure sensors is extremely demanding, as even the slightest error can lead to serious consequences. Therefore, in these cases, pressure sensors with C3 or C2 accuracy are usually chosen. In some general industrial monitoring and control applications, G1 or G2 precision pressure sensors are sufficient.

　　3. Other influencing factors

　　In addition to the accuracy class, the performance of a pressure sensor is also affected by other factors such as temperature range, stability, response time, etc. Therefore, when selecting a pressure sensor, in addition to considering the accuracy level, it is also necessary to comprehensively consider other performance indicators and the needs of practical application scenarios.

　　In addition, with the continuous development of technology, the accuracy level of pressure sensors is also increasing. In the future, we can expect more accurate, stable and reliable pressure sensors to come out to provide more powerful support for the development of various fields.

　　The accuracy level of a pressure sensor is one of the important indicators to measure its performance. When selecting a pressure sensor, it is necessary to weigh the relationship between accuracy and cost according to the needs of the actual application scenario, and comprehensively consider other performance indicators and the needs of the actual application scenario.

　　For any questions such as product consultation, product customization, agency, technical inquiry, quotation, etc., please contact Xingyi Hotline: 400-600-4496!

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