Piezoelectric Displacement Sensor

A piezoelectric accelerometer consists of a mass attached to a piezoelectric crystal which is mounted on a case.

Piezoelectric displacement sensor.

A piezoelectric transducer also known as a piezoelectric sensor is a device that uses the piezoelectric effect to measure changes in acceleration pressure strain temperature or force by converting this energy into an electrical charge. The displacement of contracting actuators is based on the transverse piezoelectric effect whereby up to approx. A transducer can be anything that converts one form of energy to another. In the datasheets the free displacements of the actuators are given at nominal voltage.

Typically piezo contractors are flat components. Their displacement occurs perpendicularly to the polarization direction and to the electric field. For many sensing techniques the sensor can act as both a sensor and an actuator often the term transducer is preferred when the device acts in this dual capacity but most piezo devices have this property of reversibility whether it is used or not. They are used for quality assurance process control and for research and development in many industries.

This charge is proportional to applied force or stress. They are very robust and are used in a wide range of industrial applications. Pierre curiediscovered the piezoelectric effect in 1880 but only in the 1950s did manufacturers begin to use the piezoelectric effect in industrial sensing applications. Piezo actuators are usually driven unipolarly.

When the accelerometer body is subjected to vibration the mass on the crystal remains undisturbed in space due to inertia. Piezoelectric sensors are versatile tools for the measurement of various processes. The piezoelectric effect produces an opposed accumulation of charged particles on the crystal. Piezoelectric pressure sensors exploit this effect by measuring the voltage across a piezoelectric element generated by the applied pressure.

20 µm is nominally achieved. Piezoelectric accelerometers rely on the piezoelectric effect of quartz or ceramic crystals to generate an electrical output that is proportional to applied acceleration. Piezoelectric sensors especially are used with high frequency sound in ultrasonic transducers for medical imaging and also industrial nondestructive testing ndt. A semibipolar operation increases the strain amplitude while causing a stronger nonlinearity and hysteresis which result from the increasing extrinsic domain portions of the displacement signal fig.

As a result the mass compresses and stretches the piezoelectric crystal. As discussed in the introduction piezo materials can transform an electrical voltage into a displacement making the material an actuator or can transform a displacement into an electrical voltage making the material a load or displacement sensor. Direct and converse piezoelectric effect.