JPH02252203A - Variable resistor - Google Patents

Abstract

PURPOSE:To eliminate an adverse influence of temperature change and to improve voltage regulating accuracy by connecting two resistors connected in series in parallel with a horseshoe-shaped resistor, and connecting its intermediate point to the center of a current collecting electrode through a conductor. CONSTITUTION:A horseshoe-shaped resistor 2 and current collecting electrodes 3, 4, 5 are provided on an insulating board 1, and the resistance is varied according to the slide contact of a rotor. Resistors 6, 7 having resistance values of one divided by several of the resistor 2 are connected in series, connected in parallel with the resistor 2, and its intermediate point is connected to the electrode 5 via a conductor 8. A power source voltage is applied to terminals 10, 11, a voltage across the resistor 6 is output, and the voltage can be altered by varying the ratio of the resistance values of the resistors 6, 7 to that of the resistor 2. Thus, a voltage regulating accuracy can be improved at a wide rotating angle without an adverse influence of the temperature change.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the structure of a variable resistor employed in electronic equipment and the like.

(Prior Art) A conventional variable resistor will be explained with reference to the accompanying drawings. The variable resistor 15 is housed in a housing h as shown in FIG. 5, and as shown in FIG. It is printed and fired on the insulating substrate 13 as shown in FIG. The current collecting electrode 18 has a first terminal 17a, the current collecting electrode 19 has a second terminal 17b, and the current collecting electrode 20 has a common terminal 17.
c are connected to each other.

Further, a rotor R provided with a wiper (not shown) is rotatably housed in the housing h so as to face the substrate 13, and the rotation of the rotor R causes the wiper to move around the horseshoe-shaped resistor 1.
The resistance can be varied by sliding on the 4. The rotor R is rotated by inserting a screwdriver or the like into a hole drilled in the north face of the rotor R.

The method of using the conventional variable resistor is as follows.

As shown in figure flB6, the voltage of the power supply 23 ■1 is variable J
It is generally used as a so-called variable voltage voltage divider that changes lIf with an lt resistor 15 and extracts an output voltage Vo from between its first terminal 17a and common terminal 17c, and between its second terminal 17b and common terminal 17C. be.

There are 5 methods for finely adjusting the voltage within a predetermined rotation angle.
As shown in FIG. 7, two resistors 21 and 22 are added to obtain the resistance value RI*R2, and the resistance value between the first terminal 17a and the common terminal 17C, and between the second terminal 17b and the common terminal 17c with respect to the rotation angle is A method is implemented to reduce the change in resistance value.

(Problems to be Solved by the Invention) In order to enable fine adjustment using the variable resistor of the conventional example, when recombining it with the variable resistor having the configuration shown in FIG. Since it is necessary to newly install fixed resistors R1 and R2, the mounting area on the printed circuit board increases, and since the temperature coefficient of the variable resistor and the fixed resistor are different, the resistance value changes depending on temperature. Changes occur,
There were various problems from a technical and manufacturing standpoint, and therefore nothing satisfactory could be obtained.

The present invention is aimed at overcoming the deficiencies and problems mentioned above.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a variable resistor configured as follows.

In other words, this variable resistor is a variable resistor in which a horseshoe-shaped resistor and a current collecting electrode are provided on a plate made of an insulator, and the resistance value is varied by the sliding contact of a rotatable rotor. Two series-connected resistors having a resistance value that is a fraction of the total resistance of the horseshoe-shaped resistor are connected in parallel with the horseshoe-shaped resistor, and an intermediate resistor between the series-connected resistors is connected in parallel with the horseshoe-shaped resistor. The point is connected to a common terminal placed at the center of the current collecting electrode via a conductor.

(Function) According to the method for manufacturing a variable resistor of the present invention, when printing a horseshoe-shaped resistor and a current collecting electrode of a variable resistor, two linear resistors and their conductors are simultaneously printed on a substrate. print on,
After that, firing can be performed simultaneously. Therefore, the same resistance paste for the horseshoe-shaped resistor of the variable resistor can be used for the linear resistor.

When the variable resistor of the present invention formed as described above is used as a variable voltage voltage divider, the output voltage is controlled to a predetermined width at the time of design so that it does not fluctuate widely depending on the temperature atmosphere. It becomes possible to do so. Furthermore, since the resistance value of the linear resistor can be controlled by controlling the pattern width, thickness, etc. formed during paste printing, variations in resistance value can also be minimized.

(Example) The present invention will be described in detail below with reference to the accompanying drawings.

? Figure t41 shows a plan view of the substrate of the variable resistor according to the present invention. In Figure 0, the symbol l is an insulating ceramic substrate, 2 is a horseshoe-shaped resistor of the variable resistor formed on the substrate, and 3, 4 and 5 are respectively The current collecting electrodes 6.7 are resistors connected to each other in a straight line, and their ends are connected to the current collecting electrodes 3 and 4, respectively, and the midpoint thereof is connected to the current collecting electrode 5 by a conductor 8. There is.

The current collecting electrodes 3, 4.5 have a first terminal 10, a second terminal 11,
Connect the common terminals 9 respectively.

Next, a method for forming a resistor of a variable resistor will be explained.

First, by screen printing on the insulating substrate 1, the current collecting electrode 3,
4.5 and conductor 8 were printed and heated at 850°C for 30 minutes in a firing furnace.
Bake in about a minute. Furthermore, a horseshoe-shaped resistor 2 and a linear resistor 6.7 are printed on the substrate l by screen printing,
Fire again. An example of using the variable resistor thus obtained as a variable voltage voltage divider is shown in FIG. 2 as an electrical equivalent circuit. A linear fixed resistor 6.7 is connected to the variable resistor of value Rr.

By supplying the voltage 1 from the power supply 12 to this equivalent circuit, the voltage VO across the fixed resistor 6 can be obtained as an output. Also, in this case, the resistance value of the fixed resistor 6゜7 is R1 + R2
By changing the ratio of the value of ' to the total resistance value Rr of the horseshoe-shaped resistor 2, the voltage can be changed as shown in A, B, and C in FIG. That is, in FIG. 3, R1=R
2=0. In the case of IRl, the curve of A, R1=R2=RI
In the case of , it is the curve B. If R1 and R2 do not exist, the curve C in the same figure will be obtained.

(Effects of the Invention) As described above in detail, according to the present invention, when a variable resistor is used as a variable voltage divider, there is no need for a separate resistor as in the conventional example. The resistance accuracy and temperature coefficient of the horseshoe-shaped variable resistor and the fixed resistor connected in series can be maintained at the same level, and a variable voltage voltage divider that is resistant to temperature changes can be obtained. Furthermore, by using the variable voltage voltage divider according to the present invention, voltage adjustment accuracy can be improved, such as high-resolution voltage setting and easy voltage adjustment work over a wide rotation angle.

[Brief explanation of drawings]

FIG. 1 is a plan view of a substrate of a variable resistor according to an embodiment of the present invention. FIG. 2 is an electrical equivalent circuit diagram of FIG. FIG. 3 is a graph showing changes in voltage in the circuit of FIG. 2. FIG. 4 is a plan view of a substrate of a conventional variable resistor. FIG. 5 is a perspective view of a conventional variable resistor. FIG. 6 is an equivalent circuit diagram of FIG. 5. FIG. 7 is a circuit diagram of a variable resistor provided with a separate resistor. l... Board, 2... Horseshoe-shaped resistor, 3, 4.5...
・Collecting electrode, 6, 7... Linear paper antibody, 8... Conductor, 9, 10.11... Terminal, 12... Power supply, 17a
, 17b, L7cm...terminal. applicant

Claims (1)

[Claims] In a variable resistor in which a horseshoe-shaped resistor and a current collecting electrode are formed on a substrate made of an insulator, and the resistance value is varied by changing the sliding contact of the rotor, Two series-connected resistors having a resistance value of 1 are connected in parallel with a horseshoe-shaped resistor, and a conductor is connected between the midpoint of the series-connected resistors and a common terminal disposed at the center of the current collecting electrode. A variable resistor characterized in that it is connected through.