JPH0684617A - Trimming resistor - Google Patents

Abstract

(57) [Summary] [Object] To provide a trimming resistor that can easily obtain a large resistance change ratio without changing the region that can be used for trimming. [Configuration] First external electrode pair 2-1 and 2-2 of first trimming resistor 21 to second external electrode pair 2-3 and 2
The adjustment groove 12-1 is formed in the film resistor 3 in the direction of -4 to cut each external electrode pair, and after this cutting is completed,
The film resistor 3 of the second trimming resistor 22 is adjusted in the same direction as the first trimming resistor 21 in the adjustment groove 12-2.
To form the first trimming resistor 21.
It is possible to adjust so as to increase the resistance value between the first external electrode pair 2-1 and 2-2, and the resistance change ratio can be easily increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip-type trimming resistor used in various electronic devices, a trimming resistor used in a trimming printed resistor circuit in a hybrid IC, and the like.

[0002]

2. Description of the Related Art A trimming resistor adjusts a resistance value of a finished film resistor while cutting or forming an adjustment groove to adjust a resistance value with high accuracy or a circuit of a circuit. The resistance value satisfying the characteristics can be obtained.

The present inventors have previously proposed a chip-type trimming resistor having four external electrodes on an insulating substrate and one film resistor connected to all the external electrodes. . This conventional chip type trimming resistor will be described with reference to the drawings.

4 (a) and 4 (b) show a thick film type chip resistor as an example of a conventional trimming resistor. FIG. 4 (a) is a plan view and FIG. 4 (b) is the same. 4 in Figure (a)
FIG. 4 is a cross-sectional view taken along line b-4b (note that a plan view is partially shaded in the same direction as the cross-sectional view for easy understanding).

As shown in FIGS. 4 (a) and 4 (b), a first and a second pair of external electrodes 2-on both ends of the rectangular parallelepiped insulating substrate 1 made of alumina or the like on the long side. 1-2-4 are formed. The external electrodes 2-1 to 2-4 are palladium-
It is made of a silver-based material and is arranged in a shape and a positional relationship that are line-symmetrical or point-symmetrical with respect to the vertical central axis of the insulating substrate 1. External electrodes 2-1 to 2-4 are provided on the insulating substrate 1.
And a thick film resistor 3 which is a film resistor and is made of a ruthenium oxide-based material. The thick film resistor 3 is covered with a protective film 4 made of low melting point glass or resin.

FIGS. 5A and 5B are shown in FIGS.
Shows an example of use in which the conventional chip-type trimming resistor shown in (b) is soldered on a wiring board to form a trimming resistor circuit. FIG. It is a front view. As shown in FIGS. 5A and 5B, a total of two pairs of first and second soldering lands 5-1 to 5-4 are formed on the wiring board 6 formed by a general method or material. Has been formed. Two pairs of external electrodes 2-1 to 2-4 of the trimming resistor 5 are provided on each soldering land 5-1 to 5-4.
Are joined by the solder 8 by a general method such as reflow, dip, or soldering iron. And the thick film resistor 3
Along the longitudinal direction from the central portion of the edge 11 between the first pair of external electrodes 2-1 and 2-2 connected to the resistor terminals 9 and 10 from above the protective film 4, that is, the second The resistance value between the resistor terminals 9 and 10 is adjusted by cutting through the adjustment groove 12 by a general method such as laser, sandblast, or cutter toward the pair of external electrodes 2-3 and 2-4. To do.

FIG. 6 is a diagram showing a resistance change ratio between the resistor terminals 9 and 10 due to the cutting of the adjusting groove 12 in the conventional example. The rate of change of the resistance value depends on the shape and dimensions of the thick film resistor 3,
Although it varies depending on the positions, dimensions, etc. of the external electrodes 2-1 to 2-4, in general, a resistance value change rate of about 10 times can be obtained in practice.

FIG. 7 is a plan view showing another usage example in which the trimming resistance circuit is formed by soldering the chip type trimming resistor 5 shown in FIGS. 4A and 4B onto the wiring board 6. (However, in order to make it easier to understand, some of them are shaded.)

In this example, as shown in FIG.
Pair of soldering lands 7-1 and 7-2 are connected to the resistor terminals 9 and 10, and the other pair of second soldering lands 7-3 and 7-4 are connected by a wiring pattern 14 for bypass. Has been done. Then, similarly, the thick film resistor 3 is similarly provided to the first pair of external electrodes 2-1 and 2-on the resistor terminals 9 and 10 side.
The adjustment groove 12 is cut from the center of the end edge 11 between the two terminals to adjust the resistance value between the resistor terminals 9 and 10. Other configurations are the same as those of the conventional example.

FIG. 8 shows resistor terminals 9 and 10 associated with the cutting of the adjusting groove 12 in the trimming resistance circuit shown in FIG.
It is a figure which shows the resistance change ratio between them. In this example, FIG.
As indicated by the chain line, the depth of cut of the adjustment groove 12 becomes deeper, and the remaining cut portion 14 of the thick film resistor 3 becomes smaller. Even if the resistance value of this portion becomes large, the current is more resistant than the remaining cut portion 14. Since the wiring pattern 14 having a lower value is shunted more, it is possible to suppress an increase in resistance value. Therefore, the adjustment groove 12 can be deeply cut to the range where a larger rate of change in resistance value is obtained. Even if the thick film resistor 3 is mistakenly completely cut off, since it is connected by the wiring pattern 14, the resistance value between the resistor terminals 9 and 10 does not become infinity but becomes a certain constant value. , Do not damage other parts or cause abnormal operation.

The inventors of the present invention have also proposed an example of use in a trimming printed resistor circuit having the same function. That is, a total of two pairs of first and second external electrodes and one film resistor connected to all of the external electrodes are formed on the wiring board, and the first pair of the two pairs of external electrodes is formed. The external electrodes of the pair are used as resistor terminals, and the external electrodes of the second pair which are not used as resistor terminals are connected to each other on the wiring board, and the film-like portion of the portion sandwiched between the external electrodes of the first pair is formed. An adjustment groove is formed in the film-shaped resistor toward the side of the film-shaped resistor sandwiched between the external electrodes of the second pair with the edge of the resistor as a cutting start point, and the resistance between the resistor terminals is increased. This is a printed resistance circuit for trimming whose value is changed. An example of use of this conventional printed resistance circuit for trimming will be described with reference to the drawings. 9A and 9B show another example in which a trimming printed resistor circuit is configured by using a trimming resistor in another conventional example, and FIG. 9A is a plan view and FIG. 9B is a cross-sectional view taken along line 9b-9b in FIG. 9A (note that the plan view is hatched in the same direction as the cross-sectional view for easy understanding).

As shown in FIGS. 9 (a) and 9 (b), two pairs of first and second palladium-silver based materials are formed on a wiring board 6 formed by a general method or material. The external electrodes 2-1 to 2-4 are formed by printing and firing. These external electrodes 2-1 to 2-4 are arranged in a point-symmetrical shape and positional relationship. In the figure, the first on the right side
The pair of external electrodes 2-1 and 2-2 are connected to and integrated with the resistor terminals 9 and 10 made of the same material as the pair of external electrodes 2-3 and 2-4 on the left side. Are interconnected and integrated by a bypass wiring pattern 14 made of a similar material. A thick film resistor 3, which is a film resistor made of a ruthenium oxide based material, is formed on the wiring board 6 by connecting the external electrodes 2-1 to 2-4 to each other and printing it in a rectangular shape and firing it. There is. Then, the thick film resistor 3 is connected to the resistor terminals 9 and 10 from the center portion of the end edge 11 between the first pair of external electrodes 2-1 and 2-2 to the other second electrode.
The resistance value between the resistor terminals 9 and 10 is adjusted by cutting the adjustment groove 12 between the pair of external electrodes 2-3 and 2-4 by a general method such as laser, sandblast, or cutter. .

FIG. 10 is a diagram showing a resistance change ratio between the resistor terminals 9 and 10 due to the notch of the adjusting groove 12 in the conventional example. In this example, as shown by the chain line in FIG. 9, the cut depth of the adjustment groove 12 becomes deep, the uncut portion 14 of the thick film resistor 3 becomes small, and even if the resistance value of this portion becomes large, the current Is a wiring pattern 1 with a lower resistance
4 allows more flow, so that an increase in resistance value can be suppressed, and even if the thick film resistor 3 is completely cut off, the thick film resistor 3 is still connected by the wiring pattern 14, so the resistor terminal 9 The resistance value between 10 and 10 does not become infinite, and shows a constant value determined by the thick film resistor 3 and the conditions of the cut.

As described above, also in the conventional trimming resistor 5, the resistance value between the resistor terminals 9 and 10 can be trimmed and adjusted by cutting the film resistor 3.

[0015]

However, the above-mentioned conventional trimming resistors have the following problems.

In the case where the trimming resistor circuit shown in FIG. 6 is formed by using the trimming resistor shown in FIG. 4, the resistor terminals 9, 9 are formed at the beginning of the cut of the film resistor 3.
The resistance value between 10 does not change so much (see FIG. 6), and after the adjustment groove 12 passes between the first pair of external electrodes 2-1 and 2-2, the resistance value between the resistor terminals 9 and 10 Will increase. As described above, while the film-shaped resistor 3 is being cut at the portion between the first pair of external electrodes 2-1 and 2-2 connected to the resistor terminals 9 and 10, it serves as a trimming resistor. Does not function. Further, the notch of the film-shaped resistor 3 progresses, and the adjustment groove is formed in the film-shaped resistor 3 between the second pair of external electrodes 2-3 and 2-4 on the side opposite to the resistor terminals 9 and 10. When 12 is formed and the uncut portion 14 is reduced, the resistance change ratio can be increased, but the resistance change ratio becomes abrupt and the resistance setting accuracy cannot be obtained. In addition, current concentration occurs in this portion, which deteriorates the stability of resistance value over time and lowers the allowable power. Further, if the film resistor 3 is accidentally completely cut, the resistance value becomes infinite (see FIG. 6), and depending on the circuit, other parts may be destroyed or abnormal operation may occur. Therefore, the area that can be used for trimming is actually limited to the area excluding the vicinity of the two pairs of external electrodes 2-1, 2-2 and 2-3, 2-4, and it is possible to obtain a larger resistance change ratio. It is impossible.

In the configuration shown in FIG. 7, the film resistor 3 is used.
At the beginning of the incision, there is a problem similar to the above (see FIG. 8). Then, the second pair of external electrodes 2-3, 2
When the adjustment groove 12 is formed in the film resistor 3 near -4, the current is bypassed by the wiring pattern 14 having a low resistance value, and the current concentration when the uncut portion 14 of the film resistor 3 becomes small. The problem due to is solved and the film resistor 3
Although the resistance value does not become infinite even if is completely cut off, the resistance value does not rise above a certain value (see FIG. 8) and does not function as a trimming resistor.
Therefore, also in this usage example, the area actually usable for trimming is two pairs of external electrodes 2-1, 2-2 and 2-.
It is limited to the parts other than around 3 and 2-4, and it is impossible to obtain a larger resistance change ratio.

On the other hand, the printed resistor for trimming formed on the wiring board 5 shown in FIG. 9 has the same problem as described above (see FIG. 10).

The present invention solves such a conventional problem, and is an excellent trimming resistor that can easily obtain a larger resistance change ratio without actually changing the region that can be used for trimming. The purpose is to provide a container.

[0020]

To achieve the above object, a film resistor formed on an insulating substrate or a wiring substrate and first and second external electrodes connected to the film resistor are provided. A first trimming resistor having a pair, a second trimming resistor having the same configuration as the first trimming resistor, the first trimming resistor and the second trimming resistor. A wiring pattern formed on the wiring board for connecting a pair of external electrodes of the resistor;
Forming trimming grooves in the film resistors of the trimming resistor and the second trimming resistor, respectively.
The resistance value between the first external electrode pair of the trimming resistor is adjusted.

[0021]

Therefore, according to the present invention, first, the adjustment groove is formed in the film resistor in the direction from the first external electrode pair of the first trimming resistor to the second external electrode pair, and each external electrode is formed. By cutting the pair, and after the cutting is completed, the film-shaped resistor of the second trimming resistor is formed with the adjustment groove in the same direction as the first trimming resistor, thereby forming the first trimming resistor. The resistance value between the first external electrode pair of the container can be adjusted to be increased, and the resistance change ratio can be easily increased.

[0022]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing an example of use in which a chip type trimming resistor formed by a thick film method according to a first embodiment of the present invention is mounted on a wiring board to form a trimming resistance circuit. There is (in order to make it easier to understand, some parts are shaded with different directions).

In FIG. 1, reference numeral 21 is a first trimming resistor, and 22 is a second trimming resistor. These first and second trimming resistors 21 and 2
In each of the two, a first and a second pair of external electrodes 2-1 to 2-4 are formed on both ends of the rectangular parallelepiped insulating substrate 1 made of alumina or the like on the long side. Each external electrode 2-1
2-4 are made of palladium-silver based material,
Are formed so as to cover the side surface, a part of the upper surface and a part of the lower surface, and are arranged in a shape and a positional relationship that are line-symmetrical or point-symmetrical with respect to the vertical central axis of the insulating substrate 1. A thick film resistor 3, which is a film resistor, is formed on the upper surface of the insulating substrate 1 so as to be connected to all the external electrodes 2-1 to 2-4 and made of a ruthenium oxide material or the like. The thick film resistor 3 is covered with a protective film 4 made of low melting point glass or resin.

On the other hand, the first and second total two pairs of soldering lands 7-1 to 7-4 are formed on the wiring board 6 formed by a general method or material and the first and second trimming resistors are used. The two pairs of external electrodes 2-1 to 2-4 of the containers 21 and 22 are provided corresponding to the respective positions. First and second
The first pair of external electrodes 2-1 and 2-2 of the trimming resistors 21 and 22 and the second pair of external electrodes 2-3 and 2-4 are the first pair of soldering lands 7-1. , 7-2 and the second pair of soldering lands 7-3, 7-4, respectively, by soldering with a common method such as reflow, dip, soldering iron, etc.
Are joined by. Then, the first pair of soldering lands 7-1 and 7-2 of the first trimming resistor 21.
Are connected to the resistor terminals 9 and 10 of the wiring board 6, and the second pair of soldering lands 7-3 and 7-4 of the first trimming resistor 21 are the wiring patterns 13 for bypass of the wiring board 6. It is connected to the. In addition, the second trimming resistor 22 and the first pair of soldering lands 7-1 and 7-2 are connected to the bypass wiring pattern 13 of the wiring board 6, and the second trimming resistor 22 is connected. The second pair of soldering lands 7-3 and 7-4 are connected to the bypass wiring pattern 14 of the wiring board 6.

Next, a method of adjusting the resistance value between the resistor terminals 9 and 10 will be described. First, with respect to the first trimming resistor 21, the first pair of external electrodes 2 connected to the thick film resistor 3 from above the protective film 4 to the resistor terminals 9 and 10.
-1, 2-2 along the longitudinal direction, that is, toward the side of the film resistor 3 sandwiched between the second pair of external electrodes 2-3, 2-4. The first adjusting groove 12-by a general method such as laser, sand blast, or cutter.
1 is formed. After the thick film resistor 3 of the first trimming resistor 21 is completely cut, the thick film resistor 3 is further cut into the second film if necessary.
First pair of external electrodes 2-of the trimming resistor 22 of
A thick film sandwiched along the longitudinal direction from the end edge 11 between the first and second 2-2, that is, between the second pair of external electrodes 2-3 and 2-4 of the second trimming resistor 22. The second adjustment groove 12-2 is formed toward the side of the resistor 3 similarly to the above.

FIG. 2 shows the adjustment groove 12- in the above embodiment.
It is a figure which shows the resistance change ratio between the resistor terminals 9 and 10 accompanying the notch of 1 and 12-2. As is clear from FIG.
When cutting the first adjustment groove 12-1, the resistance value increases according to the conventional example. In the notch in the central portion of the thick film resistor 3, a resistance change ratio of about 10 times is generally obtained. In particular, the first trimming resistor 21
When cutting the film resistor 3 sandwiched between the second pair of external electrodes 2-3, 2-4, the uncut portion of the film resistor 3 is reduced, and the first trimming resistor The resistance value of the container 21 rises sharply. However, the second pair of external electrodes 2-3, 2-4 of the first trimming resistor 21 are connected to the second trimming resistor 2 via the wiring pattern 13.
Since the second trimming resistor 22 is connected to the second trimming resistor 22, the current flowing between the resistor terminals 9 and 10 is set by appropriately setting the second trimming resistor 22 to a predetermined initial value. It is shunted to the resistor 22 for use. This makes the first
Second pair of external electrodes 2-of the trimming resistor 21 of
Even when the film resistor 3 sandwiched between 3 and 2-4 is cut, the current flowing through the second trimming resistor 22 increases, and the film resistor 3 and the second trimming resistor 22 increase. The combined resistance value with the container 22 can be increased for a while.

Next, after the thick film resistor 3 of the first trimming resistor 21 is completely cut, the second adjusting groove 12-
As is clear from FIG. 1, when the 2 is cut, the resistance value between the resistor terminals 9 and 10 is the first trimming resistor 21 and the second trimming resistor 22 after cutting.
And the combined resistance value. Therefore, as shown in FIG. 2, by cutting the second adjustment groove 12-2, the first pair of external electrodes 2-1 and 2 of the second trimming resistor 22 are cut.
The resistance value between −2 increases. In this way, the resistance value of the second trimming resistor 22 is added to the resistance value of the first trimming resistor 21, thereby significantly increasing the resistance change ratio between the resistor terminals 9 and 10. Can be made.

When the initial value of the resistance of the second trimming resistor 22 before being cut is set to the same value as the initial value of the first trimming resistor 21, the initial value of FIG. The resistance change ratio characteristic shown can be obtained. That is, the resistance change ratio between the resistor terminals 9 and 10 in this case is about 20 times.
When the initial value of the second trimming resistor 22 before being cut is set to a value smaller than the initial value of the first trimming resistor 21 (for example, 1/2), the initial value of FIG. The resistance change ratio characteristic shown in is obtained. In this case, the resistance change ratio between the resistor terminals 9 and 10 is about 15 times, but since the degree of resistance change with respect to the cut amount of the film resistor 3 becomes gentle, the resistance value setting accuracy is improved. Can be made. Further, when the initial value of the second trimming resistor 22 before being cut is set to a value larger than the initial value of the first trimming resistor 21 (for example, 5 times), the initial value of FIG. 2 becomes large. The resistance change ratio characteristic shown can be obtained, and the resistance change ratio between the resistor terminals 9 and 10 is about 60 times, and a dramatically large resistance change ratio can be realized.

Furthermore, since the second pair of external electrodes 2-3 and 2-4 of the second trimming resistor 22 are connected to the bypass wiring pattern 14 of the substrate 6, the second trimming resistor 22 is used. Even when the remaining uncut portion of the film-shaped resistor 3 of the resistor 22 is reduced, the problem such as current concentration does not occur, and even when the film-shaped resistor 3 is completely cut, the resistor terminal 9 The resistance value between 10 and 10 is not infinite.

As described above, according to the first embodiment, it is possible to easily obtain a large resistance change ratio, so that it is possible to ensure the accuracy of setting the resistance value and to cause current concentration. The stability of the resistance value over time does not decrease and the allowable power does not decrease.
Even if the thick film resistor 3 of the trimming resistor 22 is accidentally completely cut, the resistance value does not become infinite.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a plan view showing an example of use in which a trimming printed resistor circuit is constructed by using the trimming resistors according to the second embodiment of the present invention (note that in order to facilitate understanding, a part thereof is shown). It is marked with diagonal lines.).

In FIG. 3, reference numeral 21 is a first trimming resistor, and 22 is a second trimming resistor. These first and second trimming resistors 21 and 2
2 includes a wiring board 6 formed by a general method and materials, a first material made of a palladium-silver-based material,
The second total of two pairs of external electrodes 2-1 to 2-4 are formed by printing and firing. These external electrodes 2-1 to 2-4
Are arranged in a point-symmetrical shape and positional relationship.
In FIG. 3, the first pair of external electrodes 2-1 and 2-2 of the first trimming resistor 21 are connected on the wiring board 6 to the resistor terminals 9 and 10 made of a material of the same type. The second pair of external electrodes 2-3 and 2-4 of the first trimming resistor 21 which are integrated with each other are connected to the second trimming resistor 22 by the wiring pattern 13 for bypass made of a material of the same type. Are connected to the first pair of external electrodes 2-1 and 2-2. Then, the second pair of external electrodes 2-3 and 2-4 of the second trimming resistor 21 are connected to each other on the wiring board 6 by the bypass wiring pattern 14 made of a material of the same type. Are integrated. Wiring board 6
A film-shaped resistor 3 made of a ruthenium oxide-based material or the like is formed in a rectangular shape by printing and firing, which is connected to all the external electrodes 2-1 to 2-4.

Next, a method of adjusting the resistance value between the resistor terminals 9 and 10 will be described. First, with respect to the first trimming resistor 21, the first pair of external electrodes 2-1 and 2-connected to the film resistor 3 and the resistor terminals 9 and 10.
From the edge 11 between the two along the longitudinal direction, that is, the second
Toward the side of the film-shaped resistor 3 sandwiched between the pair of external electrodes 2-3, 2-4, in the same manner as in the first embodiment,
The first adjustment groove 12-1 is formed. After the film resistor 3 of the first trimming resistor 21 is completely cut, the first pair of external electrodes 2-1 and 2-2 of the second trimming resistor 22 are further cut as necessary. Along the longitudinal direction from the end edge 11 between them, that is, the side of the film resistor 3 sandwiched between the second pair of external electrodes 2-3 and 2-4 of the second trimming resistor 22. The second adjusting groove 12-2 is formed in the same manner as in the first embodiment. In this way
By forming the first and second adjustment grooves 12-1 and 12-2, the resistance value between the resistor terminals 9 and 10 is changed,
Similarly to the first embodiment, the resistance change ratio characteristic shown in FIG. 2 can be obtained in the second embodiment as well.

As described above, also in the second embodiment, a large resistance change ratio can be easily obtained. In addition, the same effect as that of the first embodiment can be obtained.

In each of the above embodiments, the thick film type trimming resistor and the printing type trimming resistor have been described. Can also obtain the same effect.

[0038]

According to the present invention, as is apparent from the above embodiment, first, the adjustment groove is formed in the film resistor in the direction from the first external electrode pair of the first trimming resistor to the second external electrode pair. By cutting each external electrode pair, and after the cutting is completed, the film-shaped resistor of the second trimming resistor is formed with an adjustment groove in the same direction as the first trimming resistor. The resistance value between the first external electrode pair of the first trimming resistor can be adjusted to be increased, and the resistance change ratio can be easily increased.

Further, during the formation of the adjusting groove in the film resistor sandwiched between the second external electrode pair of the first trimming resistor, the second trimming resistor also receives a current. The shunting has an effect that the resistance value between the first external electrode pair of the first trimming resistor can be increased in accordance with the progress of cutting.

Furthermore, the resistance change ratio between the first external electrode pair of the first trimming resistor can be arbitrarily set by appropriately selecting the initial value of the second trimming resistor before cutting. Has the effect.

[Brief description of drawings]

FIG. 1 is a plan view showing a usage example in which a trimming resistor according to a first embodiment of the present invention is mounted on a wiring board to form a trimming resistor circuit.

FIG. 2 is a characteristic diagram of a resistance change ratio obtained by the trimming resistor.

FIG. 3 is a plan view showing an example of use in which a trimming printed resistor circuit is configured using a trimming resistor according to a second embodiment of the present invention.

4A is a plan view showing a trimming resistor in a conventional example, FIG. 4B shows the trimming resistor, and FIG.
Sectional view along line 6b

FIG. 5A is a plan view showing a usage example in which the trimming resistor is mounted on a wiring board to form a trimming resistor circuit, and FIG. 5B is a front view of the trimming resistor circuit.

FIG. 6 is a characteristic diagram of a resistance change ratio obtained by the trimming resistor.

FIG. 7 is a plan view showing another usage example in which the trimming resistor in the conventional example shown in FIGS. 6A and 6B is mounted on a wiring board to form a trimming resistor circuit.

FIG. 8 is a characteristic diagram of a resistance change ratio obtained by the trimming resistor.

FIG. 9A is a plan view showing a usage example in which a trimming printed resistor circuit is configured by using a trimming resistor in another conventional example, and FIG. 9B is a front view of the trimming printed resistor circuit.

FIG. 10 is a characteristic diagram of a resistance change ratio obtained by the trimming resistor.

[Explanation of symbols]

 1 Insulating Substrate 2 External Electrode 3 Membrane Resistor 4 Protective Film 6 Wiring Board 7 Soldering Land 9 Resistor Terminal 10 Resistor Terminal 11 Edge 12 Adjustment Groove 13 Wiring Pattern 14 Wiring Pattern 21 First Trimming Resistor 22 Second trimming resistor

Claims (1)

[Claims] 1. A first trimming resistor having a film resistor formed on an insulating substrate or a wiring substrate and first and second external electrode pairs connected to the film resistor. A wiring board for connecting a second trimming resistor having the same structure as the first trimming resistor and an external electrode pair of the first trimming resistor and the second trimming resistor And a wiring pattern formed on the first trimming resistor, and the first trimming resistor and the second trimming resistor are respectively formed with adjustment grooves in the film-shaped resistors to form the first trimming resistor. A trimming resistor characterized by adjusting a resistance value between a pair of external electrodes.