Abstract: A line filter comprising a plurality of coils, one or more X capacitors is disclosed. Optionally, the line filter may comprise one or more Y capacitors. A method for constructing such a line filter is also disclosed. In one embodiment, a second X capacitor has a value approximately equal to the value of a first X capacitor if a circuit constant LT0 is less than a total inductance LT.In another embodiment, a first and third coils in combination exhibit a normal inductance of L.sub.1e, and a second and fourth coils in combination exhibit a normal mode inductance of L.sub.2e. L.sub.1e is determined at a point of intersection between a first function f1 and a second function f2, and a second capacitor has an equivalent capacitive value C.sub.X0 determined at a minimum of a third function, f3 (C.sub.X0), expressing L.sub.2e as a function of C.sub.X0.