Influence of Number of Turns on Common-Mode Choke’s Characteristics

This paper presents the characterization, simulation and modeling of common mode choke (CMC), intended to suppress electromagnetic interference. Since the knowledge of CMC characteristics is significant for the correct design of an electronic circuit to meet the electromagnetic compatibility standards, this paper presents the procedure of CMC characterizing by measuring scattering parameters (S-parameters) using a spectrum analyzer. The Open-Circuit method is used for the CMC’s electrical parameters extraction and investigating its efficiency in suppressing common-mode and differential-mode interference in the frequency range up to 50 MHz. The CMC is an inductive component comprising a commercially available toroid employed as a magnetic core and two windings of insulated wires wound around it. The ferrite material (its properties and geometry) and the windings determine CMC’s electrical characteristics (rated current, frequency range, characteristics impedance, and insertion loss). Therefore, the number of turns’ influence on its characteristics will be investigated to provide a fast design of CMC for a certain application.