Purpose: The purpose of this paper is application of approximate method of solving the task of assignment the frequency-modal analysis and characteristics of mechatronic system.Design/methodology/approach: The main approach of the subject was to formulate and solve the problem in the form of set of differential equation of motion and state equation of considered mechatronic model of object. Galerkin’s method to solving has been used. The considered torsionally vibrating mechanical system is a continuous bar of circular cross-section, clamped at one of its end. Integral part of mechatronic system is a ring transducer, extorted by harmonic voltage excitation, to be perfectly bonded to the bar surface.Findings: The parameters of the transducer have important influence of values of natural frequencies and on form of characteristics of the discused mechatronic system. The results of the calculations were not only presented in mathematical form but also as a transients of examined dynamical characteristic which were function of frequency of the excitation.Research limitations/implications: In the paper the linear mechanical subsystem and linear electric subsystem of mechatronic system has been considered, however for this kind of systems the approach is sufficient.Practical implications: The methods of analysis and obtained results can be base of design and investigation for this type of mechatronic systems.Originality/value: The mechatronic system created from mechanical and electric subsystems with electromechanical bondage has been considered. This approach is different from those considered so far.