What’s a Transducer?
A transducer is any device used to convert energy from one form to another; typically when converting input energy into output energy. For transduction to occur, a change from one form of energy must also take place, such as a conversion from mechanical to electrical energy or vice versa. The uses of transducers are widespread, impacting us in many ways. Acommon example is a microphone, which converts the input energy, the sound waves produced by a voice or instrument, to output energy, the electrical impulses in the form of amplified sound.
Other types of electroacoustic (involving a conversion between electrical energy and sound)transducers include hydrophones, which convert changes in water pressure to an electrical output, and pickups on musical instruments such as guitars, which convert the vibration of the instrument's strings into an electrical impulse.
What are Piezoelectric Transducers?
Piezoelectric transducers are a type of electroacoustic transducer that convert the electrical charges produced by some forms of solid materials into energy. The word "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 crystal 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 in numerous sizes and shapes, ceramic transducers can be easily adapted to a wide variety 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 continued to 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 to compare 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 and Uses 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.