RESEARCH & DEVELOPMENT Fig. 13 Round Wire vs. Flat Wire Fig. 14 Impedance Curve III It can be very easy to tell from Table 4 that the flat wire offers the highest impedance at the highest frequency of all the four comparison above. Finally, let's do a comparison between the traditional T-core with round wire vs rectangular core with flat wire. Table 3 - Round Wire vs. Flat Wire Fig. 13 shows two identical cores with round wire of 0.4mm diameter on the left, compared to flat wire of the same cross sectional area on the right, with identical 48 turns. From Table 3, the electrical result shows the flat wire winding provides a little higher leakage inductance, but it also shows lower DC resistance (DCR) with less than half of the parasitic capacitance. The SRF of flat wire is more than double comparing to the round wire. The Fig. 14 impedance cures result shows a big jump in the SRF for flat wire comparing to the round wire. This tells that the flat wire will offer superior noise suppression performance at higher frequency. Table 4 - Data Result 22 Magnetics Business & Technology * Summer 2018 Fig. 15 Impedance Curve IV The mechanical result shown in Table 5 indicates the area of the flat wire common mode choke is much less than the T-core common mode chokes which can save almost 40% on the PC board layout. It also has a lower profile to save about 25% of height. www.MagneticsMag.comhttp://www.MagneticsMag.com