An ultrasonic surgical apparatus including a first signal generator outputtingadrive signal at a predetermined voltage and frequency, a first oscillatingstructurereceiving the drive signal and oscillating at the frequency of the drivesignal, and abridge circuit, detecting the mechanical motion of the first oscillatingstructure andoutputting a signal representative of the mechanical motion. The apparatusalsoincludes a second oscillating structure integrally formed within a portion ofthe firstoscillating structure, the second oscillating structure outputting anelectrical signal,and a microcontroller receiving the signal output by the bridge circuit andoutput bythe second oscillating structure, the microcontroller determining aninstantaneousfrequency at which the first oscillating structure is oscillating based on thereceivedsignal, comparing the electrical signal from the second oscillating structurewith aknown signal value and determining the temperature of the second oscillatingstructure based on a the comparison.
