Ultrasonic technology is the application of ultrasonic signals that are sound waves with their frequencies of approximately 20KHz and higher. A wide variety of applications of ultrasonic technology have been developed in communication, instrumentation, imaging, welding, cleaning, etc.
Piezoelectric Effect is an effect of a piezoelectric material that external mechanical stress applied to it results in an electrical voltage across its end sides, and vise verse. The piezoelectric material consists of ions with crystal structure. The geometric structure of the crystal lattice unit cell is not center symmetric. In normal condition, the crystal is electrically neutralized as the centers of positive and negative ions coincide at the same location. When an external mechanical stress is applied to the crystal, the centers of positive and negative ions separate within each unit cell through out the crystal. Each unit cell behaves like a dipole electrically. Dipoles cancel each other within the crystal until the ends of the crystal’s surface where net charges appear, resulting a net polarization of the crystal.
A transducer is a device that exhibits the piezoelectric effect.
A piezoelectric Transducer is used to generate an ultrasonic signal.