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Piezoelectric transducers convert mechanical energy into electrical potential and vice versa using crystals or other materials. They are used in microphones, scales, accelerometers, and as generators and detectors of ultrasound. They can also be used as actuators for precise movement. The most common material used is PZT. They are reliable and rugged, unaffected by electromagnetic fields, and stable over a wide range of temperatures. They are used in industry, medicine, and aerospace work.
A piezoelectric transducer is a device that transforms one type of energy into another by exploiting the piezoelectric properties of some crystals or other materials. When a piezoelectric material is subjected to a stress or force, it generates an electric potential or voltage proportional to the magnitude of the force. This makes this type of transducer ideal as a converter of mechanical energy or force into electrical potential.
The high sensitivity of piezoelectric transducers makes them useful in microphones, where they convert sound pressure into electrical voltage, precision scales, accelerometers and motion detectors, and as generators and detectors of ultrasound. They are also used in non-destructive testing, high voltage generation, and many other applications that require precise sensing of motion or force.
The piezoelectric effect also works in reverse, in that a voltage applied to a piezoelectric material will cause that material to bend, stretch, or otherwise deform. This deformation is usually very slight and proportional to the applied voltage, so the reverse effect offers a method of movement of precision on the microscale. A transducer can therefore be used as an actuator for the exact adjustment of fine optical instruments, lasers and atomic force microscopes.
These devices can be used as both sensors and actuators, so they are referred to as transducers, a term applied to any device that can convert one form of energy into another. Consequently, both piezoelectric sensors and piezoelectric actuators fall under this heading. The sensor converts mechanical energy into electrical potential and the actuator converts electrical energy into mechanical force or motion.
The voltage generated by piezoelectric transducers can be quite high, often on the order of thousands of volts, but it is short-lived, occurring only when the material is initially deformed. This makes them useful in electronic cigarette lighters and push-button lighters for gas ranges and grills. In these applications, pressing a button activates a small spring-loaded hammer, which strikes a piezoelectric material and generates enough voltage to strike an electric arc between the exposed electrodes of the igniter.
Originally thought to be a property of only specific types of crystals such as quartz and topaz, advances in materials science have led to the creation of polymers and ceramics that also exhibit piezoelectric properties. In fact, the most common piezoelectric material currently in use is man-made ceramic lead zirconate titanate, known as PZT. This material has the ability to deliver twice the voltage of quartz under a given force.
These transducers are simple, reliable, and very rugged, so they find extensive use in industry, medicine, and aerospace work. They are unaffected by external electromagnetic fields and therefore can be used in applications where electronic sensors could fail. They are stable over a wide range of temperatures, but may be affected by prolonged use due to high temperatures.
