An ultrasonic surgical device includes a power source configured to generate power, an ultrasonic transducer electrically coupled to the power source and generating ultrasonic motion in response to the generated power, a sensor sensing current of the generated power supplied to the ultrasonic transducer, an ultrasonic probe mechanically couplable to the ultrasonic transducer, and a controller that receive a sensed current from the sensor, performs a frequency response analysis based on the sensed current, calculates 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, calculates a second resonant and second anti-resonant frequencies of the transducer based on the frequency response analysis prior to determining coupling to the ultrasonic transducer, and determines whether the ultrasonic probe is mechanically coupled to the ultrasonic transducer based on the first and second resonant and anti-resonant frequencies.