Piezoelectric

When pressure is applied to crystals, they are elastically deformed. Piezoelectric pressure sensing involves the measurement of such deformation. When a crystal is deformed, an electric charge is generated for only a few seconds. The electrical signal is proportional to the applied force. Because these sensors can only measure for a short period, they are not suitable for static pressure measurement. More suitable measurements are made of dynamic pressures caused from:

- shock

- vibration

- explosions

- pulsations

- engines

- compressors

This type of pressure sensing does not measure static pressure, and as such requires some means of identifying the pressure measured. As it measures dynamic pressure, the measurement needs to be referenced to the initial conditions before the impact of the pressure disturbance. The pressure can be expressed in relative pressure units, Pascal RELATIVE. Quartz is commonly used as the sensing crystal as it is inexpensive, stable and insensitive to temperature variations. Tourmaline is an alternative which gives faster response speeds, typically in the order of microseconds.

Advantages

- Accuracy 0.075%

- Very high pressure measurement, up to 70MPa

- small size

- robust

- fast response, < 1 nanosecond

- self-generated signal

Disadvantages

- Dynamic sensing only

- temperature sensitive

Application Limitations

Require special cabling and signal conditioning.