Principle analysis of piezoresistive pressure sensor
Pressure sensors are one of the most commonly used sensors in industrial practice and are often used as a front-end component for automated control, so they are widely used in a variety of industrial automation environments, including petrochemicals, paper, water treatment, power, marine, machine tools and utilities. Equipment and other industries.
There are many types of pressure sensors, and the most common applications include piezoresistive pressure sensors and piezoelectric pressure sensors.
Piezoresistive Pressure Transducer The piezoresistive pressure sensor works by generating a resistance change when the varistor is pressed. The pressure is detected by amplifying the amplifier and using standard pressure calibration. The performance of a piezoresistive pressure sensor is primarily determined by the pressure sensitive component (ie, varistor), the amplifier circuit, and the calibration and aging process in production.
● strain gauge
In the current pressure sensor packaging process, the piezoresistive sensitive core can usually be made compact, sensitive, and stable, and the varistor is combined with a strained material (usually stainless steel) in the form of a Wheatstone bridge. Together, this will ensure that the piezoresistive pressure sensor has high overload capacity and high impact pressure resistance.
These sensors are suitable for measuring pressure changes over a high range, especially at temperatures above 1 MPa, with good linearity and high accuracy, and are suitable for measuring a wide range of media compatible with strained materials.
Structurally, such sensors sinter the varistor in a form of a Wheatstone bridge with the ceramic. Its overload capacity is lower than that of strain gauges, its impact pressure is poor, but its sensitivity is high. It is suitable for measuring high-range range above 50Kpa, and it is corrosion-resistant and has a wide temperature range.
The corrosion-resistant ceramic pressure sensor has no liquid transfer, the pressure acts directly on the front surface of the ceramic diaphragm, causing a slight deformation of the diaphragm. The thick film resistor is printed on the back of the ceramic diaphragm and connected into a Wheatstone bridge. Bridge), due to the piezoresistive effect of the varistor, the bridge produces a highly linear voltage signal proportional to the pressure, which is proportional to the excitation voltage, and is compatible with strain gauge sensors.