An ultrasonic surgical apparatus including a first signal generator outputting a drive signal at a predetermined voltage and frequency, a first oscillating structure receiving the drive signal and oscillating at the frequency of the drive signal, and a bridge circuit, detecting the mechanical motion of the first oscillating structure and outputting a signal representative of the mechanical motion. The apparatus also includes a second oscillating structure integrally formed within a portion of the first oscillating structure, the second oscillating structure outputting an electrical signal, and a microcontroller receiving the signal output by the bridge circuit and output by the second oscillating structure, the microcontroller determining an instantaneous frequency at which the first oscillating structure is oscillating based on the received signal, comparing the electrical signal from the second oscillating structure with a known signal value and determining the temperature of the second oscillating structure based on a the comparison.
