Piezoelectric transducers convert alternating electric energy directly into mechanical energy through the use of the piezoelectric effect, in which certain materials change dimension if an electric charge is applied to them.

Electric energy at ultrasound frequency is supplied to the transducer by the ultrasound generator. This electric energy is applied to the piezoelectric element in the vibrating transducer. These vibrations are amplified by the resonating masses of the transducer and directed to the liquid through the radiation plate. Piezoelectric transducers used to use piezoelectric materials such as natural quartz crystals and barium titanate, which were fragile and unstable. Today’s transducers incorporate stronger, more efficient and highly stable piezoelectric materials developed by the US Navy during its research into the development of advanced sonar transponders in 1940. The majority of transducers used for ultrasound cleaning today make use of piezoelectric effects.