Wide-band power line noise filter using a new type of magnetic circuit

Describes a new magnetic circuit for AC power line filters. This design has high attenuation over a wide frequency range. The author developed a new magnetic circuit to decrease the stray capacitance and increase coil inductance. It consists of two loop cores joined by a mutual winding. One is a large rectangular (or equivalent oval) main core. This shape was chosen so as to reduce the stray capacitance but to maintain the same inductance as with the equivalent circular core. The other is a small rectangular auxiliary core which increases the coil inductance in the low-frequency range. The filter using the new magnetic circuit has a high attenuation of 30 dB in the frequency range of 0.15 MHz to 50 MHz