Working Principle of Common Pressure Sensors

1. Piezoresistive force sensor:

Resistor strain gauge is one of the main components of piezoresistive strain sensor. The working principle of metal resistance strain gauge is that the resistance value of strain resistor adsorbed on the base material changes with mechanical deformation, which is commonly known as resistance strain effect.

2. Ceramic pressure sensor:

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

3. Diffused silicon pressure sensor:

The working principle of diffused 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), causing the diaphragm to produce a micro-displacement proportional to the medium pressure, causing the resistance value of the sensor to change, and using electronic circuits to detect this change and convert and output a standard measurement signal corresponding to this pressure.

4. Sapphire pressure sensor:

Using the strain resistance working principle, silicon-sapphire is used as a semiconductor sensitive element, which has unparalleled metrological characteristics. Therefore, semiconductor sensitive elements made of silicon-sapphire are insensitive to temperature changes and have good working characteristics even under high temperature conditions; sapphire has extremely strong radiation resistance; in addition, silicon-sapphire semiconductor sensitive elements have no p-n drift.

5. Piezoelectric pressure sensor:

The piezoelectric effect is the main working principle of piezoelectric sensors. Piezoelectric sensors cannot be used for static measurements because the charge after the external force is only saved when the circuit has infinite input impedance. The actual situation is not like this, so this determines that piezoelectric sensors can only measure dynamic stress.