An ultrasonic surgical apparatus and method of use including a signalgeneratoroutputting a drive signal having a frequency, an oscillating structure,receiving thedrive signal and oscillating at the frequency of the drive signal, a bridgecircuit,detecting the mechanical motion of the oscillating structure and outputting asignalrepresentative of the mechanical motion, and a microcontroller receiving thesignaloutput by the bridge circuit, the microcontroller determining an instantaneousfrequency at which the oscillating structure is oscillating based on thereceived signal,and comparing the instantaneous frequency to a known frequency value andestimatinga temperature of the oscillating structure based on the comparison.
