Principles of different types of pressure transmitters

  • The principle of capacitive pressure transmitter

When the pressure directly acts on the surface of the measuring diaphragm, the diaphragm produces a small deformation. The high-precision circuit on the measuring diaphragm transforms this small deformation into a highly linear voltage proportional to the pressure and proportional to the excitation voltage. Signal, and then use a dedicated chip to convert this voltage signal into an industry standard 4-20mA current signal or 1-5V voltage signal.

  • The principle of diffused silicon pressure transmitter

The pressure of the measured medium directly acts on the diaphragm of the sensor (usually a 316L diaphragm), causing the diaphragm to produce a micro displacement proportional to the pressure of the medium, changing the resistance value of the sensor, and detecting it with a Wheatstone circuit This change, and convert and output a standard measurement signal corresponding to this pressure.

  • Principle of monocrystalline silicon pressure transmitter

Piezoresistive pressure sensors are constructed using the piezoresistive effect of single crystal silicon. Single crystal silicon wafer is used as the elastic element. When the pressure changes, the single crystal silicon produces strain, so that the strain resistance directly diffused on it produces a change proportional to the measured pressure, and then the corresponding voltage output signal is obtained by the bridge circuit .

  • Principle of ceramic pressure transmitter

The pressure directly acts 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 to a Wheatstone bridge (closed bridge) due to the piezoresistive effect of the varistor, The bridge generates a highly linear voltage signal proportional to the pressure and proportional to the excitation voltage. Generally used for pressure measurement of air compressors, more ceramics are used.

low range pressure sensor
  • Principle of strain gauge pressure transmitter

The most commonly used strain gauge pressure transmitters are metal resistance strain gauges and semiconductor strain gauges. Metal resistance strain gauge is a kind of sensitive device that converts the strain change on the test piece into an electric signal. There are two kinds of wire strain gauge and metal foil strain gauge. Usually the strain gauge is tightly bonded to the mechanical strain matrix through a special adhesive. When the matrix is subjected to a stress change, the resistance strain gauge also deforms, so that the resistance value of the strain gauge changes, so that The voltage applied to the resistor changes. Strain gauge pressure transmitters are relatively rare on the market.

  • Sapphire pressure transmitter

The sapphire pressure transmitter uses the strain resistance working principle, adopts high-precision silicon-sapphire sensitive components, and converts the pressure signal into a standard electrical signal through a dedicated amplifier circuit.

  • Sputtering film pressure transmitter

The sputtering pressure sensitive element is manufactured by microelectronics technology, forming a firm and stable Wheatstone bridge on the surface of the elastic stainless steel diaphragm. When the pressure of the measured medium acts on the elastic stainless steel diaphragm, the Wheatstone bridge on the other side produces an electrical output signal proportional to the pressure. Due to its good impact resistance, sputtered films are often used in occasions with frequent pressure impacts, such as hydraulic equipment.

Picture of Jade Luo
Jade Luo
Hi, I’m Jade Luo, the funder of cictechcn.com, I’ve been running a factory in China that makes Industrial sensors and flow meters for 8 years now, and the purpose of this article is to share with you the knowledge related to sensors from a Chinese supplier’s perspective.
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