Abstract: A spiral LC composite member is formed by splicing together a desired number of rectangular dielectric chips between two spiral coils with rectangular cross sections. A noise-cut filter circuit is formed by laminating and connecting a desired number of spiral LC composite members. A desired number of noise-cut filter circuits are layered through insulation sheets, and are enclosed by a magnetic body so that a magnetic circuit can be formed at the core and the outer circumference of the multi-layered body. This constructs a filter circuit serving as a reactor and a capacitor.

Abstract: A method of manufacturing a noise-cut filter having distributed inductances and distributed capacitances is produced wherein conductive spiral coil patterns are formed on the opposite surfaces of a dielectric sheet, such that the spiral coil patterns are aligned with each other in a direction perpendicular to the plane of the dielectric sheet, and a main circuit pattern is constructed by bonding a main circuit conductor to the spiral coil pattern formed on one of the opposite surfaces of the dielectric sheet. The main circuit conductor is formed by stamping with a punch press so that the conductor has a cross sectional area large enough to allow the passage of current of a main circuit, and has substantially the same shape as the spiral coil pattern.

Abstract: A noise-cut filter having distributed inductances and distributed capacitances is provided wherein conductive spiral coil patterns are formed on the opposite surfaces of a dielectric sheet, such that the spiral coil patterns are aligned with each other in a direction perpendicular to the plane of the dielectric sheet, and a main circuit pattern is constructed by bonding a main circuit conductor to the spiral coil pattern formed on one of the opposite surfaces of the dielectric sheet. The main circuit conductor is formed by stamping with a punch press so that the conductor has a cross sectional area large enough to allow the passage of current of a main circuit, and has substantially the same shape as the spiral coil pattern.

Abstract: A noise-cut filter device for a power converter, including at least one noise-cut filter, for filtering switching noise occurring upon a switching operation of a semiconductor switching device of the power converter is disclosed. In this filter device, the noise-cut filter includes first and second planar conductors, and a dielectric sheet having upper and lower surfaces on which the first and second conductors are disposed to face each other through the dielectric sheet. The first and second planar conductors cooperate with the dielectric sheet to form a circuit having both functions of an inductor and a condenser. The current of a main circuit of the power converter flows through the opposite ends of the first planar conductor, while the current based on the switching noise, which flows from the first conductor to the second conductor, is led to ground by the second conductor.