#$%^&*AU2019250279A120191107.pdf#####ABSTRACT There is disclosed a system for vibrating the tip of an ultrasonic handpiece, the handpiece having at least one driver to which an AC drive signal is applied to vibrate the tip, the system including: a control console to output the AC drive signal； means to measure a voltage of the AC drive signal； means to measure a current of the AC drive signal； and a processor configured: to calculate, based on the voltage of the AC drive signal, the current of the AC drive signal, a frequency of the AC drive signal and a capacitance of the at least one driver, an equivalent of current applied to mechanical components of the handpiece； and to set the frequency of the AC drive signal based on a current applied to the at least one driver and said equivalent.
