What is the Difference Between Piezoelectric and Piezoresistive?

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The main difference between piezoelectric and piezoresistive materials lies in the way they respond to mechanical force:

  • Piezoelectric materials generate a voltage when a mechanical force is applied to them. These materials are capable of converting mechanical energy to electrical energy and vice versa. Ceramic and quartz crystal are common piezoelectric materials used for sensing pressure. Applications include microphones, which use quartz crystals for transducing pressure into electricity, and pressure sensors in various industries.
  • Piezoresistive materials change their resistivity when subjected to a mechanical force. These materials convert mechanical energy to resistance values, but they do not transform resistance into energy like piezoelectric transducers. The piezoresistive effect is used in strain gauges for measuring pressure, and silicon pressure sensors are an example of devices that utilize this effect. Piezoresistive sensors can operate purely as sensors and do not have a reverse mode, unlike piezoelectric sensors.

In summary, piezoelectric materials generate a voltage in response to mechanical force, while piezoresistive materials change their resistivity in response to mechanical force. Piezoelectric devices convert mechanical energy to electrical energy and vice versa, while piezoresistive devices convert mechanical energy to resistance values.

Comparative Table: Piezoelectric vs Piezoresistive

Here is a table summarizing the differences between piezoelectric and piezoresistive materials:

Property Piezoelectric Piezoresistive
Definition The ability of a material to generate a voltage when mechanical force is applied. The ability of a material's resistivity to change when subjected to mechanical stress.
Energy Conversion Converts mechanical energy to electrical energy and vice versa. Converts mechanical energy to resistance values, but does not convert resistance levels to other forms of energy.
Commonly Used Materials Crystals, ceramics, and some biological materials like bones, DNA, and proteins. Semiconductor materials, strain gauges, and some metals like platinum alloys and nickel.
Applications Pressure sensors, microphones, underwater explosion detection. Strain gauges for measuring pressure, resistance-based sensors.
Reversibility Can convert electrical energy to mechanical energy. Cannot convert resistance levels to other forms of energy.

In summary, piezoelectric materials generate a voltage when subjected to mechanical force, while piezoresistive materials change their resistivity when subjected to mechanical stress. Piezoelectric components can convert both mechanical and electrical energy, while piezoresistive components only convert mechanical energy to resistance values and do not work in reverse.