A method for calculating the capacitance of a transducer (C0) without knowing the exact resonance frequency of a transducer/blade combination is achieved by sweeping across a broad frequency range which contains resonant and non-resonant frequencies where C0 can be measured. A pre-defined frequency range is set independently of the resonance frequency of a specific transducer/blade combination. C0 of the transducer/blade is measured at several different frequencies within the pre-defined frequency range to ensure that invalid C0 measurements are disregarded, and the temperature of the transducer is calculated based on valid C0 measurements. The determined transducer temperature, based on C0 measurements, can be used to optimize performance and/or provide a safety shutdown mechanism for the generator.