Abstract: A bidirectional power line filter provides distributive capacitance to accomplish filtering is electrically connected between the power lines and the ground wire in a power distribution system. In addition to lumped parameter or fixed value capacitors, a distributive capacitance is provided by use of a printed circuit board upon which the electrical components forming the filter are mounted. A specially formed dual inductor is wound as a common-core inductor using two toroidal cores preferably formed of ferrite each having a different permeability verus frequency curve. The inventive filter is intended for use in a three-phase Y-connected power distribution system, as well as in a conventional single-phase system. An additional multiple outlet system may be added to the bidirectional filter and it is also formed having distributive capacitance by employing a length of printed circuit board material to which the plurality of outlets are connected.