A piezoelectric sensor measures force and pressure through the principle of the piezoelectric effect. The piezoelectric effect refers to the property of certain materials to generate an electric charge in response to mechanical stress or deformation. Conversely, when an electric charge is applied to these materials, they undergo a mechanical deformation or change in shape.
Piezoelectric sensors are typically made from materials like quartz, piezoelectric ceramics (e.g., lead zirconate titanate - PZT), or some polymers. When force or pressure is applied to the sensor, it causes a mechanical deformation in the piezoelectric material. This deformation results in a separation of positive and negative charges within the material, creating an electric charge across the sensor's surface.
To measure the generated electric charge and convert it into a usable signal, the piezoelectric sensor is equipped with electrodes that collect the charge and transmit it to external circuitry. This external circuitry can then amplify the signal and convert it into a measurable voltage or current, which is proportional to the force or pressure applied to the sensor.
The magnitude of the electrical charge generated is directly related to the force or pressure applied to the piezoelectric sensor. Therefore, by measuring the electrical output of the sensor, the force or pressure can be accurately determined.
Piezoelectric sensors have numerous applications due to their sensitivity, fast response time, and ability to measure dynamic events. Some common applications include force and pressure measurements in industrial machinery, impact testing, vibration analysis, pressure sensors in automotive applications, and even in medical devices to measure physiological signals like blood pressure.