A transducer is optimally driven at or near its resonant frequency by a driver system that adapts to variations and/or changes to the resonant frequency of the transducer due to variations in piezo materials, manufacturing, assembly, component tolerances, and/or operational conditions. The system may include an output controller, a phase track controller, a frequency generator, a drive, circuitry to determine a phase angle between the transducer voltage and transducer current, and circuitry to obtain transducer admittance from the transducer voltage and transducer current.