JP2001250721A - Variable inductance coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil which can be easily and finely regulated in inductance. SOLUTION: A coil is equipped with coil patterns 1 and 2 of a conductor printed on an insulating board 10, where points that are each on the coil patterns 1 and 2 and adjacent to each other are shorted with a jumper to determine the inductance of the coil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil formed by printing a conductor on a circuit board.

[0002]

2. Description of the Related Art When a tuning circuit or the like is formed on a substrate, a printed coil pattern is used. For example, as shown in FIG. 7, a coil is formed by printing the conductor 1 on an insulating substrate 10 in a loop shape. Such a coil is suitable for mass production of the same product because it is formed by printing, but the pattern is determined and the inductance L is fixed. In order to form a coil by changing the inductance even slightly, there is an inconvenience that the pattern must be changed from the pattern of the printing original plate. Therefore, in the case of an LC tuning circuit or the like, the tuning frequency is finely adjusted by changing the capacitance with a trimmer capacitor while keeping the inductance unchanged.

[0003]

As described above, the conventional tuning circuit has a problem in that a capacitor used with the coil requires a trimmer capacitor for fine adjustment of the frequency, and the number of components is increased.

An object of the present invention is to provide a coil capable of fine-tuning the frequency of a tuning circuit by changing the inductance itself without using a trimmer capacitor. Is what you do.

[0005]

According to an embodiment of the present invention, there is provided a coil according to an embodiment of the present invention, comprising a plurality of coils drawn on an insulating substrate 10 by a conductor, as shown in FIG. The coil patterns 1 and 2 are arranged in rows, and the positions adjacent to the coil patterns 1 and 2 in a plurality of rows are short-circuited by a jumper 4 (see FIG. 2) to determine the inductance.

[0006] Inductance L between the end 1a and the end 1b of the coil 1 in the above configuration is not to constitute a coil 2 is circuit as shown in the equivalent circuit of FIG. 1, the L ₁ from only coil 1 contributes Become. When the coil 1 and the coil 2 as shown in FIG. 2 are short-circuited by the jumper 4, because the inductance L ₂ of the coil 2 coil 1 contributes is divided into inductance L ₃ and the inductance L _4, the end 1a inductance between the end _{1b L = L 2 · L 3} / (L
A _{2 + L 3) + L 4} .

More specifically, as shown in FIG. 3, a convex portion 8 or a concave portion formed on the jumper 4 is fitted to a concave portion 9 or a convex portion formed on the surface of the coil pattern 1 (and 2). .

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a coil according to an embodiment of the present invention. FIG. 1 shows a plan view of an embodiment of a coil to which the present invention is applied, together with an equivalent circuit thereof. As shown in the figure, coil patterns 1 and 2 made of copper are formed on a bakelite substrate 10 by printing. The coil pattern 1 orbits substantially from the end 1a to the end 1b. Coil pattern 2 is coil pattern 1 and end 1a
Are common and parallel in the middle, but are interrupted in the middle. On the surface of the coil pattern 1, two holes 9 and 13 forming a concave portion are formed. The hole 9 has a longitudinal section shown in FIG.
As shown in the figure, the copper coil pattern 1 is penetrated to the bakelite substrate 10. The same applies to the holes 13.
Similar holes 12 and 1 are provided on the surface of the coil pattern 2.
4 has been opened. The holes 12 are aligned with the holes 9 of the coil pattern 1 and are positions where the coil patterns 2 are interrupted. The hole 14 is at a position aligned with the hole 13.

On the other hand, the jumper 4 is formed by pressing a metal plate to form two projections 8 (see FIG. 3). The center-to-center distance of the protrusion 8 is the same as the center-to-center distance between the two holes 9 and 12 (same for holes 13 and 14). The maximum diameter of the projection 8 is a slightly larger fitting diameter than the hole 9 (the holes 12, 13, and 14 are also the same).

[0010] In the coil of this configuration, forming the circuit only at the end 1a and the end 1b without marked a jumper when used as the inductance L ₁ of the coil 1 (see the equivalent circuit of FIG. 1). When adjusting the inductance of the coil, the two projections 8 of the jumper 4 are fitted into the holes 9 and 12, respectively, and the coils 1 and 2 are connected at the positions of the holes 9 and 12, and the circuit shown in FIG. The configuration is as shown.

Incidentally, by short-circuiting only the positions of the holes 13 and 14, it is possible to adjust the equivalent circuit and the inductance to be different from those in FIG. Further, by using two jumpers 4, the positions of the holes 9 and 12 can be short-circuited, and the positions of the holes 13 and 14 can be short-circuited.

In the embodiment shown in FIG. 1, the short-circuit position by the jumper 4 has two systems (the systems of the holes 9 and 12, and the hole 13).
And 14), but if more holes are provided to increase the short-circuit position, the inductance can be further adjusted to various values.

FIG. 4 is a plan view of another embodiment of a coil to which the present invention is applied, together with an equivalent circuit thereof. As shown in the drawing, the coil pattern 1 substantially circulates from the end 1a to the end 1b, and the coil pattern 2 circulates substantially from the end 2a to the end 2b in parallel with the coil pattern 1.

FIG. 5 shows a coil having such a configuration.
Thus, the end 1a of the coil pattern 1 is
Between the end 2a and between the end 1b of the coil pattern 1 and the coil.
Between the end 2b of the metal pattern 2 and a solder as a jumper
5 and the solder 6 respectively. Then configured
Inductance of the equivalent circuit L = L₁・ L₂/ (L₁+
L ₂).

Further, as shown in FIG. 6, the center between the coil pattern 1 and the center of the coil pattern 2 is further short-circuited by solder 7. The inductance L of the equivalent circuit configured at that time is L = _L1a · _L2a / ( _L1a + _L2a ) + L
_1b · L _2b / (L _1b + L _2b )

[0016]

As described above, in the coil to which the present invention is applied, the inductance can be easily finely adjusted by the jumper. Therefore, in order to finely adjust the frequency in the tuning circuit using this coil, components such as a trimmer capacitor are not required, and the circuit can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment of a coil to which the present invention is applied and an equivalent circuit diagram thereof.

FIG. 2 is a plan view showing an operating state of the coil of the embodiment and an equivalent circuit diagram thereof.

FIG. 3 is a longitudinal sectional view showing details of the coil of the embodiment.

FIG. 4 is a plan view of another embodiment of a coil to which the present invention is applied and an equivalent circuit diagram thereof.

FIG. 5 is a plan view showing an example of a use state of the coil of the another embodiment and an equivalent circuit diagram thereof.

FIG. 6 is a plan view and an equivalent circuit diagram showing another example of a use state of the coil of the another embodiment.

FIG. 7 is a plan view showing an example of a conventional coil formed on a substrate and an equivalent circuit diagram thereof.

[Explanation of symbols]

1 and 2 are coil patterns, 1a, 1b, 2a and 2b are ends, 4 is a jumper, 5.6.7 is solder, 8 is a protrusion, 9
12, 13, 14 are holes, and 10 is an insulating substrate.

Claims (2)

[Claims] The present invention is characterized in that a plurality of rows of coil patterns drawn by a conductor are formed on an insulating substrate, and inductance is determined by short-circuiting adjacent positions of the plurality of rows of coil patterns with a jumper. Coil. 2. The coil according to claim 1, wherein a convex portion or a concave portion formed on a jumper is fitted to a concave portion or a convex portion formed on a surface of the coil pattern.