A piezoelectric transducer is a device that transforms one type of energy to another by taking advantage of the piezoelectric properties of certain crystals or other materials. When a piezoelectric material is subjected to stress or force, it generates an electrical 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 electric potential.
The high sensitivity of piezoelectric transducers makes them useful in microphones, where they convert sound pressure into electric voltage, in precision balances, in accelerometers and motion detectors, and as generators and detectors of ultrasound. They are also used in non-destructive testing, in the generation of high voltages, and in many other applications requiring the 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 voltage applied, and so the reverse effect offers a method of precision movement on the micro scale. A transducer may, therefore, be used as an actuator for the exact adjustment of fine optical instruments, lasers, and atomic force microscopes.
Piezoelectric transducers are a type of electroacoustic transducer that convert theelectrical charges produced by some forms of solid materials into energy. Theword “piezoelectric” literally means electricity caused by pressure. An early application of piezo transducer technology occurred during World War I with the use of sonar, which used echoes to detect the presence of enemy ships.
What are Typical Piezo Transducer Materials?
Originally,crystals made from quartz were used as a material for piezoelectric transducers. In the early 1950s, quartz crystals began to give way to piezoelectric ceramic as the primary transducer material. The advantages offered by a ceramic transducer when compared to other materials include ceramic’s ability to be manufactured in a wide variety of shapes and sizes, its capability of operating efficiently at low voltage, and its ability to function at temperatures up to 300oC.
Due to the ability of producing a ceramic transducer innumerous sizes and shapes, ceramic transducers can be easily adapted to a widevariety of industrial applications. Consequently, they allow for complete customization to meet a customer’s specific needs. Today, the most commonly used ceramic transducer manufacturing materials are lead zirconate titanate compositions, a trend that traces its origins to the 1960s. As ceramic transducer technology has continuedto evolve, the use of piezo-polymers and composites has likewise gained acceptance.
How to Measure Piezo Transducer Efficiency
One way to measure the efficiency of a transducer is tocompare the amount of input energy versus output energy. Anytime energy conversion occurs, some amount of energy will be lost during the process. In general, the greater the amount of output energy produced in relation to input energy, the greater the level of efficiency that is present.
The Piezoelectric Ultrasonic Transducer
A piezoelectric ultrasonic transducer generates ultrasonic activity, meaning it produces sound waves above the frequencies that can be heard by the human ear. It functions by rapidly expanding and contracting when appropriate electrical frequency and voltage is applied. Typically used in cleaning systems, the expansion and contraction causes the ultrasonic diaphragm, which serves as the pressure-sensing element of the transducer, to vibrate, introducing ultrasonic activity into the cleaning tank in the process. The piezoelectric ultrasound transducer also offers the advantages of high electroacoustic efficiency while minimizing heat generation.
Applications for Piezoelectric Transducers
Piezoelectric transducers can be used for numerous applications for industrial, environmental and personal use. Air transducers, for instance, are frequently used in automobile, proximity and level sensors. They are commonly used in residential products like motion and object detectors, pest deterrents and home security alarms. They are also used in electronic devices, such as toys, games and remote control units.