DRIVING DEVICE OF PIEZOELECTRIC ELEMENT

摘要

PURPOSE:To reduce the ringing, by detecting the current flowing near the point of resonance of a pizeoelectric element and then applying a negative feedback to the input side. CONSTITUTION:A video head 2 is attached to the tip of a piezoelectric element 1, and the rear edge of the element 1 is fixed to a supporter 3. The oscillators 1' and 1'' bend in the direction of polarization to have a mechanical displacement in accordance with the level of application voltage which is supplied between terminals 4a and 4b connected to the oscillators 1' and 1'' respectively. The output of a piezoelectric element drive signal generator 5 is applied to the terminal 4a of the element 1 via an adder 6 and an amplifier 7. The terminal 4b is earthed via a resistance 8. The current flowing to the element 1 is converted into the voltage signal by the resistance 8 and then negatively fed back to the adder 6 via a filter 9, a phase shifter 10 and a gain control volume 11.