A piezoelectric sensor is a type of transducer that converts mechanical energy (such as pressure or acceleration) into an electrical signal. It relies on the piezoelectric effect, a property of certain materials that generate an electric charge when subjected to mechanical stress. This effect occurs due to the arrangement of atoms within the material.
Here's a basic explanation of how a piezoelectric sensor works:
Piezoelectric Material: The sensor is made of a piezoelectric material, typically crystals or ceramics such as quartz, lead zirconate titanate (PZT), or polyvinylidene fluoride (PVDF). These materials have a unique property: when subjected to mechanical deformation, their internal positive and negative charges get displaced, creating an electric potential across the material.
Mechanical Stress: When an external force is applied to the piezoelectric sensor, it undergoes mechanical stress or deformation. This force could be in the form of pressure, acceleration, vibration, or any other physical input that causes the material to change shape.
Electric Charge Generation: As the piezoelectric material deforms, the arrangement of charges inside the material shifts, leading to a separation of positive and negative charges. This separation results in the generation of an electric charge across the material.
Electric Signal: The electric charge generated is tiny but measurable. To extract useful information from the sensor, it is connected to an external circuit. The charge is converted into a voltage output, which can be amplified and further processed to obtain meaningful data about the applied force or mechanical input.
Applications: Piezoelectric sensors find applications in various fields, including pressure sensors in industrial applications, accelerometers in automotive airbag systems, touch sensors in consumer electronics, and more. They are particularly useful in situations where a compact and durable sensor is needed to measure mechanical phenomena accurately.
It's worth noting that the piezoelectric effect also works in reverse. When an electric voltage is applied to a piezoelectric material, it deforms or changes shape. This property is used in piezoelectric actuators, which convert electrical energy into mechanical motion, and they are employed in various devices like inkjet printers, ultrasonic transducers, and more.