Views: 780 Author: Site Editor Publish Time: 2020-09-15 Origin: Site
Piezoresistive strain gauge sensors
These are the earliest and most widely used type of pressure sensor.
The simple construction means low cost and durability. The sensors are robust with good resistance to shock, vibration, and dynamic pressure changes.
The readout circuits are very simple and enable high-resolution measurement.
The output is linear with pressure and the response time is typically below one millisecond.
They can be used for a wide range of pressure measurements from 3 psi up to about 20,000 psi (21 kPa to 150 MPa). The output is also stable over time.
The resistive elements can be bonded to the diaphragm, thin film resistors can be created directly on the membrane. These can operate at higher temperatures and are more suitable for use in harsh environments.
The main disadvantage is that the sensor has to be powered. This makes them unsuitable for low power or battery operated systems. Scaling down the size reduces the resistance and increases the power consumption.
There are also limitations on scaling because strain averaging reduces the sensitivity of the sensor. However, very small sensors can be fabricated as MEMS devices.
The sensor output is temperature dependent. This can be a big disadvantage for applications such as tyre pressure measurement where there are large temperature changes over the operating cycle.
Temperature compensation would greatly reduce the temperature drift.