JP7397815B2 - Thermal switching elements and electrical circuits - Google Patents

Description

The present invention relates to a thermally responsive switching element and the like.

BACKGROUND ART Conventionally, as an example of a thermally responsive switching element, a breaker that cuts off current in response to a rise in temperature has been known (see, for example, Patent Document 1).

WO2011/105175 publication

In the thermally responsive switching element disclosed in Patent Document 1, the movable contact contacts the fixed contact during normal times, and a conductive state is maintained between the movable piece and the fixed piece. Joule heat is generated. Therefore, the temperature of the thermally responsive element becomes a temperature obtained by adding the temperature increased by the Joule heat to the ambient temperature of the thermally responsive switching element, and there is a possibility that the ambient temperature of the thermally responsive switching element cannot be accurately sensed.

The present invention was devised in view of the above-mentioned circumstances, and provides a thermally responsive switching element that operates accurately in response to a rise in temperature around the thermally responsive switching element without being affected by Joule heat. That is the main purpose.

A first aspect of the present invention has a fixed contact and a movable contact, a movable piece that presses the movable contact to contact the fixed contact, and elastically deforms the movable piece, so that the movable contact is moved from the fixed contact to the movable piece. a thermally responsive element that separates the movable contact and operates the movable piece such that the movable contact contacts the fixed contact by deforming with temperature change, the thermally responsive element having a first thermal expansion a first layer having a coefficient of thermal expansion and a second layer having a second coefficient of thermal expansion higher than the first coefficient of thermal expansion, and the first layer is on the side of the fixed contact in the thickness direction of the thermally responsive element. , the second layer is disposed on the movable contact side.

A second invention of the present invention has a fixed contact and a movable contact, and a movable piece that presses the movable contact to contact the fixed contact, and elastically deforms the movable piece, so that the movable contact is moved from the fixed contact to the a thermally responsive element that separates the movable contact and operates the movable piece such that the movable contact contacts the fixed contact by deforming with temperature change, the thermally responsive element having a first thermal expansion a first layer having a coefficient of thermal expansion, and a second layer having a second coefficient of thermal expansion higher than the first coefficient of thermal expansion, and the second layer is on the side of the movable piece in the thickness direction of the thermally responsive element. It is arranged.

The thermally responsive switching element according to the present invention includes a case having a space for accommodating the fixed contact, the movable piece, and the thermally responsive element, and the case has a bottom wall and a side of the thermally responsive element from the bottom wall. It is desirable to have a contact portion that protrudes from the top and contacts the first layer.

In the thermally responsive switching element according to the present invention, the case includes a penetration penetrating through the case in a region that overlaps with a part of the thermally responsive element in a plan view viewed from the thickness direction of the thermally responsive element. Preferably, holes are formed.

A third aspect of the present invention is an electric circuit including the thermally responsive switching element, a power source, and a load, wherein the thermally responsive switching element is connected in series to a power line connecting the power source and the load. has been done.

A fourth aspect of the present invention is an electric circuit including the thermally responsive switching element, a power source, and a load, wherein the thermally responsive switching element is connected to the load through a power line connecting the power source and the load. are connected in parallel.

In the thermally responsive switching element of the first aspect of the present invention, the thermally responsive element separates the movable contact from the fixed contact by elastically deforming the movable piece in a state where Joule heat is not generated. The movable piece is actuated so that the movable contact contacts the fixed contact by deforming the movable piece. Thereby, the thermally responsive switching element operates accurately in response to a rise in temperature around the thermally responsive switching element without being affected by Joule heat generated by the fixed contact, the movable contact, and the movable piece. Further, the thermally responsive element includes the first layer having the first coefficient of thermal expansion and the second layer having the second coefficient of thermal expansion higher than the first coefficient of thermal expansion, In the thickness direction, the first layer is disposed on the fixed contact side, and the second layer is disposed on the movable contact side. Therefore, the above-mentioned accurate operation can be obtained without increasing the thickness of the thermally responsive switching element.

In the thermally responsive switching element of the first aspect of the present invention, the thermally responsive element separates the movable contact from the fixed contact by elastically deforming the movable piece in a state where Joule heat is not generated. The movable piece is actuated so that the movable contact contacts the fixed contact by deforming the movable piece. Thereby, the thermally responsive switching element operates accurately in response to a rise in temperature around the thermally responsive switching element without being affected by Joule heat. Further, the thermally responsive element includes the first layer having the first coefficient of thermal expansion and the second layer having the second coefficient of thermal expansion higher than the first coefficient of thermal expansion, The second layer is arranged on the side of the movable piece in the thickness direction. Therefore, the above-mentioned accurate operation can be obtained without increasing the thickness of the thermally responsive switching element.

1 is a perspective view showing a schematic configuration of a thermally responsive switching element according to an embodiment of the present invention before assembly; FIG. FIG. 3 is a cross-sectional view showing the thermally responsive switching element with its contacts in an open state. FIG. 3 is a cross-sectional view showing the thermally responsive switching element with its contacts in a closed state. FIG. 2 is a perspective view showing the configuration of a modified example of the case body in FIG. 1; FIG. 5 is a plan view showing the relationship between the thermally responsive element and the through hole in the case body of FIG. 4; FIG. 2 is a circuit diagram showing an electric circuit including the thermally responsive switching element of FIG. 1. FIG. 7 is a circuit diagram showing an electric circuit different from the electric circuit of FIG. 6. FIG.

A thermally responsive switching element according to an embodiment of the present invention will be described with reference to the drawings. 1 to 3 show the configuration of a thermally responsive switching element 1. FIG. The thermally responsive switching element 1 includes a fixed contact 21, a movable piece 4 having a movable contact 41, and a thermally responsive element 5 that deforms with temperature changes. In the thermally responsive switch element 1 of this embodiment, the fixed contact 21, the movable contact 41, the movable piece 4, and the thermally responsive element 5 are provided inside the case 10. The case 10 includes a case body (first case) 7, a lid member (second case) 8 attached to the case body 7, and the like.

The fixed contact 21 is provided on the fixed piece 2. The fixing piece 2 is formed, for example, by pressing a metal plate mainly composed of copper or the like (in addition, a metal plate of copper-titanium alloy, nickel silver, brass, etc.), and is inserted into the case body 7 by insert molding. embedded. The fixed piece 2 has a terminal 22 that is electrically connected to an external circuit. The terminal 22 protrudes outward from the side wall at the edge of the case body 7.

The fixed contact 21 is formed at a position facing the movable contact 41 by cladding, plating, or coating with a highly conductive material such as silver, nickel, nickel-silver alloy, copper-silver alloy, or gold-silver alloy. , is exposed through a part of an opening 73a formed inside the case body 7.

In this application, unless otherwise specified, the surface of the fixed piece 2 on which the fixed contact 21 is formed (i.e., the upper surface in FIG. 2) is the first surface, and the opposite surface is the second surface. It is explained as. When the direction from the fixed contact 21 to the movable contact 41 is defined as a first direction, and the direction opposite to the first direction is defined as a second direction, the first surface faces the first direction, and the second surface faces the second direction. Turn in the direction. The same applies to other parts, such as the movable piece 4 and the thermally responsive element 5.

The movable contact 41 is formed at the tip of the movable piece 4 in the longitudinal direction. The movable contact 41 is made of the same material as the fixed contact 21, for example, and is joined to the tip of the movable piece 4 by welding, cladding, crimping, or other methods.

The movable piece 4 is formed into an arm shape symmetrical with respect to a longitudinal center line by pressing a plate-shaped metal material whose main component is copper or the like. The movable piece 4 presses the movable contact 41 against the fixed contact 21 to bring it into contact.

A terminal 42 electrically connected to an external circuit is formed at the other end of the movable piece 4 in the longitudinal direction. The terminal 42 protrudes outward from the side wall at the edge of the case body 7. The movable piece 4 has a fixed part 43 and an elastic part 44 between the movable contact 41 and the terminal 42.

The fixing part 43 is provided between the terminal 42 and the elastic part 44, and is fixed by being sandwiched between the case body 7 and the lid member 8 from both sides. This stabilizes the position and posture of the movable piece 4 with respect to the case body 7.

The elastic portion 44 extends from the fixed portion 43 to the movable contact 41 side. That is, the movable contact 41 is provided at the tip of the elastic part 44 extending from the fixed part 43.

The movable piece 4 is fixed by the case body 7 and the lid member 8 in the fixed part 43, and the elastic part 44 is elastically deformed, so that the movable contact 41 formed at the tip thereof moves in the thickness direction of the movable piece 4. , the distance between the fixed contact 21 and the movable contact 41 changes, and the opening and closing of the thermally responsive switching element 1 is realized.

The movable piece 4 is curved or bent at the elastic portion 44 by press working. The degree of curvature or bending is not particularly limited as long as the thermally responsive element 5 can be accommodated, and may be appropriately set in consideration of the elastic force at the operating temperature and return temperature, the pressing force of the contact points, etc. Further, a pair of protrusions (contact parts) 44a and 44b are formed on the second surface of the elastic part 44 so as to face the thermally responsive element 5. The projections 44a, 44b and the thermally responsive element 5 are in contact with each other, and the deformation of the thermally responsive element 5 is transmitted to the elastic portion 44 via the projections 44a, 44b (see FIGS. 2 and 3).

The thermally responsive element 5 operates the movable piece 4 by deforming with temperature changes. The thermally responsive element 5 is constructed by laminating two types of materials having different coefficients of thermal expansion.

The thermally responsive element 5 has an initial shape curved into an arc, and is formed by laminating thin plates having different coefficients of thermal expansion. When the operating temperature is reached due to overheating, the curved shape of the thermally responsive element 5 is reversely warped with a snap motion, and is restored when the temperature drops below the return temperature due to cooling. The initial shape of the thermally responsive element 5 can be formed by press working. The material and shape of the thermally responsive element 5 are not particularly limited, but a rectangular shape is desirable from the viewpoint of productivity and efficiency of the reverse warping operation. It is desirable that it be a close rectangle.

The case body 7 and lid member 8 that make up the case 10 are molded from thermoplastic resin such as flame-retardant polyamide, polyphenylene sulfide (PPS) with excellent heat resistance, liquid crystal polymer (LCP), and polybutylene terephthalate (PBT). has been done. Insulating materials other than resins may be used as long as they can provide properties equivalent to or better than those of the resins described above.

The case body 7 is formed with an accommodation recess 73 which is an internal space for accommodating the fixed contact 21, the movable piece 4, the thermally responsive element 5, and the like. The accommodation recess 73 has openings 73a and 73b for accommodating the movable piece 4, an opening 73c for accommodating the movable piece 4 and the thermally responsive element 5, and the like. Note that the edge of the thermally responsive element 5 incorporated into the case body 7 is appropriately abutted by a frame formed inside the housing recess 73, and is guided when the thermally responsive element 5 is thermally deformed.

A cover piece 9 is embedded in the lid member 8 by insert molding (see FIG. 2). The cover piece 9 is formed into a plate shape by press-working a metal whose main component is copper or the like mentioned above or a metal such as stainless steel. As shown in FIGS. 2 and 3, the cover piece 9 appropriately contacts the first surface of the movable piece 4 to regulate the movement of the movable piece 4, and also to maintain the rigidity of the lid member 8 and, ultimately, the case 10 as a housing. - Contributes to miniaturization of the thermally responsive switching element 1 while increasing strength.

As shown in FIG. 1, the lid member 8 is attached to the case body 7 so as to close the openings 73a, 73b, 73c, etc. of the case body 7 that accommodates the fixed contact 21, the movable piece 4, the thermally responsive element 5, etc. be done. The case body 7 and the lid member 8 are joined by, for example, ultrasonic welding. At this time, the case body 7 and the lid member 8 are continuously joined over the entire circumference of their respective outer edges, and the airtightness of the case 10 is improved. As a result, the internal space of the case 10 provided by the accommodation recess 73 is sealed, and components such as the fixed contact 21, the movable piece 4, and the thermally responsive element 5 are isolated from the atmosphere outside the case 10 and can be protected. Further, the fixed portion 43 of the movable piece 4 is welded to the case body 7 and the lid member 8 by ultrasonic welding.

FIG. 2 shows the operation of the thermally responsive switching element 1 at normal temperature. As shown in FIGS. 1 and 2, the thermally responsive element 5 at the normal temperature maintains its initial shape convex toward the second direction. The thermally responsive element 5 in its initial shape contacts the protrusions 44a and 44b at both ends of the thermally responsive switching element 1 in the longitudinal direction. At this time, the thermally responsive element 5 generates an elastic force greater than the elastic force generated by the elastic part 44 of the movable piece 4, and pushes up the protrusion 44b at the tip of the movable piece 4 toward the first direction. 4 is maintained in a cut-off state in which the movable contact 41 is separated from the fixed contact 21. Therefore, since Joule heat is not generated due to energization between the fixed piece 2 and the movable piece 4, the temperature of the thermally responsive element 5 becomes a temperature that accurately reflects the temperature around the thermally responsive switching element 1.

FIG. 3 shows the operation of the thermally responsive switching element 1 at abnormal temperatures. When the ambient temperature of the thermally responsive switching element 1 rises excessively, the thermally responsive element 5 that has reached the operating temperature deforms into a shape that is convex toward the first direction. The operating temperature of the thermally responsive element 5 is, for example, 70°C to 90°C. As the thermally responsive element 5 deforms, the force with which the thermally responsive element 5 was pushing up the elastic part 44 disappears or significantly decreases, and the elastic force of the elastic part 44 pushes the movable contact 41 toward the fixed contact 21 and fixes it. Contact point 21 is contacted. As a result, the movable piece 4 transitions to a conductive state.

In the thermally responsive switching element 1, the thermally responsive element 5 separates the movable contact 41 from the fixed contact 21 by elastically deforming the movable piece 4 in the absence of Joule heat, and is movable by deforming with temperature changes. The movable piece 4 is operated so that the contact 41 contacts the fixed contact 21. Thereby, the thermally responsive switching element 1 is not affected by Joule heat generated by the fixed contact 21, the movable contact 41, and the movable piece 4, and operates accurately in accordance with the temperature rise around the thermally responsive switching element 1.

As shown in FIGS. 2 and 3, the thermally responsive element 5 includes a first layer 51 having a first coefficient of thermal expansion, and a second layer 52 having a second coefficient of thermal expansion higher than the first coefficient of thermal expansion. It is composed of so-called bimetal. The first layer 51 is made of, for example, an alloy of iron-nickel alloy, nickel silver, brass, stainless steel, or the like. The second layer 52 is made of a material made of an alloy such as a copper-nickel-manganese alloy or a nickel-chromium-iron alloy. The thermally responsive element 5 may be formed of a trimetal or the like having a laminated structure of three or more layers.

In the present thermally responsive switching element 1, the first layer 51 is disposed on the fixed contact 21 side and the second layer 52 is disposed on the movable contact 41 side in the thickness direction of the thermally responsive element 5. That is, the first layer 51 is arranged on the second direction side, and the second layer 52 is arranged on the first direction side. This arrangement makes it possible to position the fixed contact 21, the movable contact 41, and the thermally responsive element 5 side by side in the longitudinal direction of the thermally responsive switching element 1, without increasing the thickness of the thermally responsive switching element 1. , the above operation can be obtained accurately.

Furthermore, in the present thermally responsive switching element 1, the second layer 52 is disposed on the movable piece 4 side in the thickness direction of the thermally responsive element 5. This arrangement makes it possible to position the fixed contact 21, the movable contact 41, and the thermally responsive element 5 side by side in the longitudinal direction of the thermally responsive switching element 1, without increasing the thickness of the thermally responsive switching element 1. , the above operation can be obtained accurately.

As shown in FIGS. 1 to 3, the case body 7 preferably has a bottom wall 75 and a contact portion 76 that contacts the thermally responsive element 5. As shown in FIGS. The contact portion 76 protrudes from the bottom wall 75 toward the thermally responsive element 5 and comes into contact with the first layer 51 of the thermally responsive element 5 . That is, the thermally responsive element 5 is placed above the contact portion 76 in FIG.

As shown in FIG. 2, the thermally responsive element 5 in its initial shape contacts the contact portion 76 at its center. Thereby, the thermally responsive element 5 is positioned closer to the first direction than the bottom wall 75, and a sufficient distance between the movable contact 41 and the fixed contact 21 in the cut-off state is ensured. Therefore, even if the thermally responsive switching element 1 is subjected to a shock for some reason, the state in which the movable contact 41 is separated from the fixed contact 21 can be easily maintained, and the operation of the thermally responsive switching element 1 can be easily maintained. becomes stable.

FIG. 4 shows a case body 7A that is a modification of the case body 7. As shown in FIG. For parts of the case body 7A that are not explained below, the configuration of the case body 7 described above may be adopted. A through hole 77 passing through the bottom wall 75 is formed in the case body 7A.

By providing the through hole 77 in the bottom wall 75 of the case body 7A, external heat of the thermally responsive switching element 1 is easily transmitted to the thermally responsive element 5 through radiation and convection, thereby improving the response performance and sensitivity of the thermally responsive switching element 1. Characteristics etc. will improve. When the response performance of the thermally responsive switching element 1 improves, the difference between the temperature of the external environment of the thermally responsive switching element 1 and the operating temperature of the thermally responsive element 5 becomes smaller, making it possible to more safely protect the electric circuit. .

As shown in FIGS. 2 and 3, in the case where the fixing piece 2 extends to the area of the bottom wall 75, the through hole 77 may pass through the fixing piece 2. By penetrating the fixed piece 2 with the through hole 77, external heat of the thermally responsive switching element 1 is easily transmitted to the thermally responsive element 5 by radiation and convection. On the other hand, in a configuration in which the through hole 77 does not penetrate the fixed piece 2, the airtightness of the housing recess 73 in the case 10 is enhanced. Further, heat outside the thermally responsive switching element 1 is easily transmitted to the thermally responsive element 5 via the terminal 22.

FIG. 5 shows the relationship between the thermally responsive element 5 and the through hole 77. The through hole 77 is formed in a region that overlaps a part of the thermally responsive element 5 when viewed in plan from the thickness direction of the thermally responsive element 5 . Such an arrangement allows heat from outside the thermally responsive switching element 1 to be transmitted to the thermally responsive element 5 even more easily.

In the case body 7A, three through holes 77 having the same shape are formed. The shape and number of through holes 77 are arbitrary. A bridge portion 78 connecting the bottom wall 75 and the contact portion 76 is provided between each through hole 77 . The position of the contact portion 76 is stabilized by the bridge portion 78, and the position of the movable contact 41 relative to the fixed contact 21 is also stabilized.

FIG. 6 shows an electrical circuit 100 including the thermally responsive switching element 1. As shown in FIG. Electric circuit 100 includes thermally responsive switching element 1 , power source 101 , and load 102 . A power supply 101 applies a driving voltage to a load 102 via a power line 103. In the electric circuit 100, the thermally responsive switching element 1 is connected in series to a power line 103 that connects a power source 101 and a load 102.

The thermally responsive switching element 1 is provided at or near a heat source (not shown). The heat source may be a load different from load 102 within electrical circuit 100 or may be independent of electrical circuit 100. The load 102 is a cooling device for cooling a heat source. An example of a cooling device is an electric fan for cooling a heat source. The cooling device may be an electric fan or a heat exchange device for removing heat from a heat source.

In the electric circuit 100 during normal operation, the thermally responsive switching element 1 is in an open state in which the movable contact 41 is separated from the fixed contact 21. At this time, the drive voltage of the power supply 101 is not applied to the load 102.

On the other hand, in the electric circuit 100, when the heat source overheats, the movable contact 41 comes into contact with the fixed contact 21 due to thermal deformation of the thermally responsive element 5, and the thermally responsive switching element 1 shifts to the closed state. At this time, a driving voltage is applied to the load 102, which is a cooling device, and the heat source is cooled. When the thermally responsive element 5 restores its original shape as the temperature of the heat source decreases, the thermally responsive switching element 1 returns to the open state. The temperature of the heat source is controlled by such an electric circuit 100.

FIG. 7 shows a circuit diagram of an electric circuit 100A that is a modification of the electric circuit 100. Similar to the electric circuit 100, the electric circuit 100A includes a thermally responsive switching element 1, a power source 101, and a load 102. A power supply 101 applies a driving voltage to a load 102 via a power line 103. In the electric circuit 100, the thermally responsive switching element 1 is connected in parallel to the load 102 via a power line 103 that connects the power source 101 and the load 102. Further, a load other than the load 102 (for example, a resistor 104) is connected in series to the thermally responsive switching element 1.

In electrical circuit 100A, the heat source includes load 102 within electrical circuit 100A. The thermally responsive switching element 1 is provided at or near a load 102 that is a heat source.

In the electric circuit 100A during normal operation, the thermally responsive switching element 1 is in an open state in which the movable contact 41 is separated from the fixed contact 21. At this time, the drive voltage of the power supply 101 is applied to the load 102.

On the other hand, in the electric circuit 100, when the heat source overheats, the movable contact 41 comes into contact with the fixed contact 21 due to thermal deformation of the thermally responsive element 5, and the thermally responsive switching element 1 shifts to the closed state. At this time, the drive voltage of the power supply 101 is also applied to the thermally responsive switching element 1, and a portion of the current flowing through the load 102 is bypassed. Therefore, the current flowing through the load 102 is limited, and overheating of the load 102, which is a heat source, is suppressed. Then, when the thermally responsive element 5 restores its original shape as the temperature of the load 102 decreases, the thermally responsive switching element 1 returns to the open state. The temperature of the heat source is controlled by such an electric circuit 100.

Although the thermally responsive switching element 1 of the present invention has been described in detail above, the present invention is not limited to the above-described specific embodiments, but can be implemented by changing various aspects. That is, the thermally responsive switch element 1 has at least a fixed contact 21 and a movable contact 41, and a movable piece 4 that presses the movable contact 41 into contact with the fixed contact 21, and a movable piece 4 that elastically deforms. , a thermally responsive element 5 that separates the movable contact 41 from the fixed contact 21 and operates the movable piece 4 so that the movable contact 41 comes into contact with the fixed contact 21 by deforming with temperature change, the thermally responsive element 5 5 has a first layer 51 having a first coefficient of thermal expansion and a second layer 52 having a second coefficient of thermal expansion higher than the first coefficient of thermal expansion. 51 may be disposed on the fixed contact 21 side, and the second layer 52 may be disposed on the movable contact 41 side.

The thermally responsive switch element 1 has at least a fixed contact 21 and a movable contact 41, and a movable piece 4 that presses the movable contact 41 into contact with the fixed contact 21, and a movable piece 4 that elastically deforms. , a thermally responsive element 5 that separates the movable contact 41 from the fixed contact 21 and operates the movable piece 4 so that the movable contact 41 comes into contact with the fixed contact 21 by deforming with temperature change, the thermally responsive element 5 5 has a first layer 51 having a first coefficient of thermal expansion and a second layer 52 having a second coefficient of thermal expansion higher than the first coefficient of thermal expansion. 52 may be disposed on the side of the movable piece 4.

1 Thermal response switch element 4 Movable piece 5 Thermal response element 10 Case 21 Fixed contact 41 Movable contact 51 First layer 52 Second layer 75 Bottom wall 76 Contact portion 77 Through hole 100 Electric circuit 100A Electric circuit 101 Power supply 102 Load 103 Power line

Claims (6)

fixed contacts,
a movable piece having a movable contact and pressing the movable contact against the fixed contact;
A thermal response in which the movable piece is elastically deformed to separate the movable contact from the fixed contact, and the movable piece is actuated so that the movable contact comes into contact with the fixed contact by deforming with a temperature change. Equipped with an element,
The thermally responsive element has a first layer having a first coefficient of thermal expansion and a second layer having a second coefficient of thermal expansion higher than the first coefficient of thermal expansion,
In the thickness direction of the thermally responsive element, the first layer is disposed on the fixed contact side, and the second layer is disposed on the movable contact side.
Thermal response switching element. fixed contacts,
a movable piece having a movable contact and pressing the movable contact against the fixed contact;
A thermal response in which the movable piece is elastically deformed to separate the movable contact from the fixed contact, and the movable piece is actuated so that the movable contact comes into contact with the fixed contact by deforming with a temperature change. Equipped with an element,
The thermally responsive element has a first layer having a first coefficient of thermal expansion and a second layer having a second coefficient of thermal expansion higher than the first coefficient of thermal expansion,
The second layer is disposed on the movable piece side in the thickness direction of the thermally responsive element.
Thermal response switching element. comprising a case having a space for accommodating the fixed contact, the movable piece, and the thermally responsive element;
The thermally responsive switching element according to claim 1, wherein the case has a bottom wall and a contact portion that protrudes from the bottom wall toward the thermally responsive element and contacts the first layer. According to claim 3, the case is formed with a through hole that penetrates the case in a region that overlaps with a part of the thermally responsive element when viewed in a plan view from the thickness direction of the thermally responsive element. The thermally responsive switching element described. An electric circuit comprising the thermally responsive switching element according to any one of claims 1 to 4, a power source, and a load,
The thermally responsive switching element is connected in series to a power line connecting the power source and the load.
electric circuit. An electric circuit comprising the thermally responsive switching element according to any one of claims 1 to 4, a power source, and a load,
The thermally responsive switching element is connected in parallel to the load through a power line connecting the power source and the load.
electric circuit.

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