Abstract: Provided is a method for determining an operating range of an ultrasonic vibrating unit (7), which ultrasonic vibrating unit (7) is supplied with electrical power by a generator (2) via an output (2a) and is excited to vibrate ultrasonically, wherein at least constituent parts of the ultrasonic vibrating unit (7), preferably an ultrasonic transducer (8) contained therein, and constituent parts of the generator (2), preferably a matching network (2b) on the output side, form a tuned circuit (2c, 2d). The method is characterized in that a measuring circuit (3) is connected upstream of the output (2a) of the generator (2), via the measuring circuit (3), a voltage (U) is applied to the tuned circuit, and by the measuring circuit (3), at least the phase, preferably magnitude and phase, of an impedance of the tuned circuit are measured, and at least the phase, preferably the phase and magnitude, of the impedance are evaluated in order to determine the working range.

Abstract: Provided is a method for determining an operating range of an ultrasonic vibrating unit (7), which ultrasonic vibrating unit (7) is supplied with electrical power by a generator (2) via an output (2a) and is excited to vibrate ultrasonically, wherein at least constituent parts of the ultrasonic vibrating unit (7), preferably an ultrasonic transducer (8) contained therein, and constituent parts of the generator (2), preferably a matching network (2b) on the output side, form a tuned circuit (2c, 2d). The method is characterized in that a measuring circuit (3) is connected upstream of the output (2a) of the generator (2), via the measuring circuit (3), a voltage (U) is applied to the tuned circuit, and by the measuring circuit (3), at least the phase, preferably magnitude and phase, of an impedance of the tuned circuit are measured, and at least the phase, preferably the phase and magnitude, of the impedance are evaluated in order to determine the working range.