JPH03748Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a through-type noise filter inserted into a power line or a signal line to remove high frequency noise.

Conventional feed-through noise filters of this type include ones that combine ferrite beads with a feed-through capacitor, but integrating the ferrite beads complicates the internal structure and increases the external dimensions. There was an inconvenience.

In view of the above points, the present invention focuses on the fact that ferrite beads are both magnetic and dielectric, and aims to provide a through-type noise filter with a simple structure and good high-frequency noise removal effect. That is.

Embodiments of the through-type noise filter according to the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, the cylindrical ferrite bead 1 is selected to have a high specific resistance of around 100 MΩ, and a first inner electrode 2A is formed on the left end surface and the left inner peripheral surface of the cylindrical ferrite bead 1. A second inner electrode 2B is formed on the right end surface and the right inner peripheral surface. An outer electrode 3 is formed at the middle part of the outer peripheral surface of the cylindrical ferrite bead 1, and an annular external terminal 4 is connected to the outer electrode 3. Then, the center conductor 5 is inserted into the through hole on the inner circumference of the cylindrical ferrite bead, and the first and second inner electrodes 2
Connected to A and 2B.

According to the above configuration, the center conductor 5 acts as an inductor due to the magnetic permeability of the ferrite beads 1,
Further, since a capacitor is formed almost continuously between the inner and outer circumferences of the ferrite bead 1 due to the dielectric constant of the ferrite bead 1, it can be considered that a distributed constant filter is equivalently formed. Therefore, it is extremely effective in removing noise in the high frequency region, particularly in the ultra high frequency band and extremely high frequency band of 100 MHz or more. Furthermore, since the ferrite beads 1 serve as both a magnetic material and a dielectric material, the structure is extremely simple and the mechanical strength is greater than that of a ceramic dielectric material.

Although the inner electrode is divided into two parts, the left side and the right side, it may be one continuous electrode, or it may be divided into three or more parts. Further, the shape of the external terminal can be changed as appropriate.

As described above, according to the present invention, it is possible to obtain a through-type noise filter that has a simple structure and is excellent in the effect of removing high frequency noise.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a through-type noise filter according to the present invention, and FIG. 2 is a longitudinal sectional view thereof. 1... Ferrite bead, 2A, 2B... Inner electrode, 3... Outer electrode, 4... External terminal, 5...
center conductor.

Claims (1)

[Scope of utility model registration request] An inner electrode is formed on the inner circumferential surface and both end surfaces of a cylindrical ferrite bead with high specific resistance, and an outer electrode is formed on the outer circumferential surface except for both end portions, and a center conductor is inserted through the cylindrical ferrite bead to form the inner electrode. , and a ring-shaped external terminal is connected to the outer electrode.