The capacitors used in EMI filters are generally ceramic capacitors, which are also known as feed-through capacitors due to their physical structure.
        The self inductance of feed-through capacitors is much smaller than that of ordinary capacitors, so the self resonant frequency is very high. What’s more, the through hole design effectively prevents high-frequency signals from directly coupling from the input end to the output end. This combination of low-pass and high impedance provides excellent suppression effect in the 1GHz frequency range. Learn More