What is a piezoelectric pressure sensor?
The piezoelectric pressure sensor is a sensor that uses the piezoelectric effect of piezoelectric materials to convert the measured pressure into an electrical signal. Use electrical components and other machinery to convert the pressure to be measured into electricity. Measuring precision instrument for related measurement work. Such as pressure transmitters and pressure sensors.
Piezoelectric pressure sensor working principle
Piezoelectric pressure sensors are mainly based on the piezoelectric effect (Piezoelectric effect). Use electrical components and other machinery to convert the pressure to be measured into electricity. Then perform measurement precision instruments such as pressure transmitters and pressure sensors.
Piezoelectric sensors can not be used in static measurement. The reason is the electric charge after the action of external force. When the circuit has infinite input resistance, it can be preserved.
But this is not the case.
Therefore, piezoelectric sensors can only be used in dynamic measurements.
Its main piezoelectric materials are: dihydrogen phosphate, sodium potassium tartrate and quartz. The piezoelectric effect is found on quartz.
When the stress changes, the electric field changes very little, and some other piezoelectric crystals will replace quartz.
Potassium sodium tartrate, it has a large piezoelectric coefficient and piezoelectric sensitivity. However, it can only be used indoors where the humidity and temperature are relatively low.
Dihydrogen phosphate is a kind of artificial crystal. It can be used in high humidity and high temperature environment. Therefore, its application is very wide.
With the development of technology, the piezoelectric effect has also been applied to polycrystals. For example: piezoelectric ceramics, niobate magnesium acid piezoelectric ceramics, niobate series piezoelectric ceramics and barium titanate piezoelectric ceramics, etc. are included.
The sensors based on the piezoelectric effect are electromechanical conversion and self-generation sensors. Its sensitive components are made of piezoelectric materials.
When the piezoelectric material is subjected to an external force, an electric charge will be formed on its surface. The electric charge will be amplified by the charge amplifier, the measuring circuit and the impedance converted. It will be converted into an electrical output proportional to the external force received.
It is used to measure force and non-electrical physical quantities that can be converted into force. For example: acceleration and pressure.
It has many advantages: lighter weight, reliable work, simple structure, high signal-to-noise ratio, high sensitivity and signal bandwidth, etc.
But it also has some shortcomings: some voltage materials are protected from moisture. Therefore, a series of moisture-proof measures need to be taken. And the output current response is relatively poor. Then it is necessary to use a charge amplifier or a high input impedance circuit to make up for this shortcoming. Make the instrument work better.
Extended reading: Silicon Pressure Sensor
Piezoelectric pressure sensor advantages and disadvantages
- The advantages are bandwidth, high sensitivity, high signal-to-noise ratio, simple structure, reliable work, and lightweight.
- The disadvantage is that some piezoelectric materials need moisture-proof measures. And the output DC response is poor. It is necessary to use a high input impedance circuit or a charge amplifier to overcome this defect.
Extended Reading: Digital Pressure Sensor-RS485
The working principle of 5 common pressure sensors
In addition to the Piezoelectric Pressure Sensors described in this article, there are many pressure transmitters and pressure sensors that can convert pressure into electrical signals.
So how do these pressure transmitters and pressure sensors convert pressure signals into electrical signals? What are the characteristics of different conversion methods?
Here, I have summarized the measurement principles of several common pressure sensors for everyone. hope that it can help us.
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Extended Reading: Up to 800°C High Temperature Pressure Sensor
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