An ultrasonic surgical device (100, 200) comprising: a power source (110, 210) configured to generate power; an ultrasonic transducer (150, 250) electrically coupled to the power source and configured to generate ultrasonic motion in response to the generated power; a sensor configured to sense current of the generated power supplied to the ultrasonic transducer; an ultrasonic probe (190, 290) configured to be mechanically couplable to the ultrasonic transducer; and a controller configured to: receive sensed current from the sensor; perform a frequency response analysis based on the sensed current; calculate a first resonant frequency and a first anti-resonant frequency of the transducer prior to coupling the ultrasonic probe based on the frequency response analysis; calculate a first coupling coefficient based on the first resonant frequency and the first anti-resonance frequencies; calculate a second resonant frequency and a second anti-resonant frequency of the transducer based on the frequency response analysis prior to determining whether the ultrasonic probe is coupled to the ultrasonic transducer; and calculate a second coupling coefficient based on the second resonant frequency and the second anti-resonance frequencies; and determine whether the ultrasonic probe is mechanically coupled to the ultrasonic transducer based on the first and second coupling coefficients, wherein the controller is configured to determine whether the ultrasonic probe is mechanically coupled to the ultrasonic transducer based on a comparison of a difference between the first and second coupling coefficients with a predetermined threshold. a power source (110, 210) configured to generate power; an ultrasonic transducer (150, 250) electrically coupled to the power source and configured to generate ultrasonic motion in response to the generated power; a sensor configured to sense current of the generated power supplied to the ultrasonic transducer; an ultrasonic probe (190, 290) configured to be mechanically couplable to the ultrasonic transducer; and a controller configured to: receive sensed current from the sensor; perform a frequency response analysis based on the sensed current; calculate a first resonant frequency and a first anti-resonant frequency of the transducer prior to coupling the ultrasonic probe based on the frequency response analysis; calculate a first coupling coefficient based on the first resonant frequency and the first anti-resonance frequencies; calculate a second resonant frequency and a second anti-resonant frequency of the transducer based on the frequency response analysis prior to determining whether the ultrasonic probe is coupled to the ultrasonic transducer; and calculate a second coupling coefficient based on the second resonant frequency and the second anti-resonance frequencies; and determine whether the ultrasonic probe is mechanically coupled to the ultrasonic transducer based on the first and second coupling coefficients, wherein the controller is configured to determine whether the ultrasonic probe is mechanically coupled to the ultrasonic transducer based on a comparison of a difference between the first and second coupling coefficients with a predetermined threshold. receive sensed current from the sensor; perform a frequency response analysis based on the sensed current; calculate a first resonant frequency and a first anti-resonant frequency of the transducer prior to coupling the ultrasonic probe based on the frequency response analysis; calculate a first coupling coefficient based on the first resonant frequency and the first anti-resonance frequencies; calculate a second resonant frequency and a second anti-resonant frequency of the transducer based on the frequency response analysis prior to determining whether the ultrasonic probe is coupled to the ultrasonic transducer; and calculate a second coupling coefficient based on the second resonant frequency and the second anti-resonance frequencies; and determine whether the ultrasonic probe is mechanically coupled to the ultrasonic transducer based on the first and second coupling coefficients, wherein the controller is configured to determine whether the ultrasonic probe is mechanically coupled to the ultrasonic transducer based on a comparison of a difference between the first and second coupling coefficients with a predetermined threshold.