DE102023107507A1 - Method for providing an SMD component and corresponding SMD component - Google Patents

Abstract

The invention relates to a method for providing an SMD component, in particular an SMD current measuring resistor, with the following steps:• producing the SMD component with a predetermined nominal value (RNENN) of a component characteristic of the SMD component and a certain manufacturing tolerance (±ΔRFERT) of the component characteristic (R),• measuring a measured value (RMESS) of the component characteristic of the SMD component with a certain measuring tolerance (±ΔRMESS), wherein the measuring tolerance (±ΔRMESS) is more precise than the manufacturing tolerance (±ΔRFERT), and• applying a code to the SMD component, wherein the code contains information about the measured measured value (RMESS) of the component characteristic (R) of the SMD component and/or the measuring tolerance (±ΔRMESS).The invention further comprises a corresponding SMD component.

Description

Technical field of the invention

The invention relates to a method for providing an SMD component (SMD: surface mounted device), in particular a low-resistance SMD current measuring resistor. The invention further relates to a corresponding SMD component.

Background of the invention

From the state of the art (e.g. EP 0 605 800 A1 ) are low-resistance current measuring resistors, also known as shunts, which are used to measure current using the four-wire technique. The electrical current to be measured is passed through the low-resistance current measuring resistor, whereby the voltage drop across the low-resistance current measuring resistor is a measure of the electrical current flowing through the current measuring resistor according to Ohm's law.

Furthermore, it is known from the prior art to design such low-resistance current measuring resistors as SMD components. When using such an SMD current measuring resistor to measure current, it is important that the resistance value matches a specified nominal value as closely as possible, i.e. a very precise manufacturing tolerance is desirable in order to enable precise current measurement. Deviations of the actual resistance value of the SMD current measuring resistor from the specified nominal value lead to a measurement error when calculating the electrical current in accordance with Ohm's law. However, the costs for producing such an SMD current measuring resistor depend on the manufacturing tolerance of the resistance value, i.e. achieving an accurate manufacturing tolerance is associated with relatively high manufacturing costs. In the prior art, there is therefore a conflict of objectives between the desire for the most accurate manufacturing tolerance possible with small deviations of the resistance value from the nominal value on the one hand and the desire for the most cost-effective manufacturing possible on the other.

Description of the invention

The invention is therefore based on the object of resolving the conflict of objectives described above.

This object is achieved by a method according to the invention or a corresponding SMD component according to the independent claims.

The method according to the invention initially provides that an SMD component is produced with a predetermined nominal value of a component characteristic of the SMD component and a certain manufacturing tolerance of the component characteristic, as is known per se from the prior art. It should be mentioned here that the invention is not limited to a specific manufacturing method for producing the SMD component.

In a preferred embodiment of the invention, the SMD component is a low-resistance SMD current measuring resistor. However, the technical teaching of the invention can also be implemented in principle with other component types, such as capacitors or inductors, to name just two examples.

In the preferred embodiment of the invention, the nominal value of the SMD component is the specified resistance value, while the manufacturing tolerance defines the permissible range of fluctuation of the resistance value around the nominal value. However, the invention is not limited to the resistance value with regard to the nominal value, but can also be implemented with other component parameters. For example, the nominal value of a capacitor can be the capacitance.

Furthermore, the method according to the invention provides for a measurement of a measured value of the component characteristic of the SMD component, the measurement being carried out with a specific measurement tolerance depending on the measuring principle used. It is important here that the measurement tolerance is more precise than the manufacturing tolerance. The invention therefore combines cost-effective production of the SMD component with an inaccurate manufacturing tolerance with a measurement of the component characteristic with a more precise measurement tolerance. This resolves the conflict of objectives described at the beginning between the desire for the most precise manufacturing tolerance possible on the one hand and the desire for a cost-effective manufacturing process on the other. It is not necessary within the scope of the invention to use an expensive manufacturing process with a correspondingly precise manufacturing tolerance. Rather, within the scope of the invention, a cost-effective manufacturing process with a correspondingly inaccurate manufacturing tolerance can also be used. The actual value of the component characteristic is then only determined in the context of a subsequent measurement with a more precise measurement tolerance.

Furthermore, the method according to the invention provides that a code is applied to the SMD component, the code containing information about the measured value of the component characteristic of the SMD component and/or about the measurement tolerance. For the sake of clarity, it should be mentioned that when using an SMD current measuring resistor in a measuring circuit, it is not particularly important that the SMD current measuring resistor used adheres to a specific nominal value of the resistance value as precisely as possible. What is more important when using an SMD current measuring resistor in a measuring circuit is that the resistance value is known as precisely as possible with the smallest possible tolerance, since the exact value of the resistance value can then be taken into account in the measuring circuit. It is therefore not important for current measurement according to the four-wire technique that the SMD current measuring resistor used adheres to a specified nominal value as precisely as possible. What is more important is that the measuring circuit knows the actual resistance value of the current measuring resistor used as precisely as possible and can then take this into account when calculating the electrical current flowing through the current measuring resistor in accordance with Ohm's law. For this reason, it is important that the measured SMD component is provided with a code that reflects the measured value and/or the measurement tolerance. When the SMD component is mounted in an electronic measuring circuit, this code can then be read out in order to subsequently take the measured value and/or the measurement tolerance into account when operating the measuring circuit.

Furthermore, the method according to the invention preferably provides that an electronic circuit (e.g. measuring circuit) is equipped with the SMD component according to the invention. In this case, the position and/or orientation of the SMD component is preferably recorded using an optical image processing system, as is known per se from the prior art. The position and/or orientation of the SMD component is then corrected according to the position and/or orientation of the SMD component determined by the image processing system in order to be able to equip the circuit with the SMD component as precisely as possible. The circuit is then equipped with the SMD component after the position and/or orientation of the SMD component has been corrected.

The code applied to the SMD component can then be read by the image processing system, which is also used to detect the position and/or orientation of the SMD component when assembling the circuit. In the context of the invention, no separate image processing system is therefore required to read the code applied to the SMD component.

However, within the scope of the invention, it is also possible in principle for a separate image processing system to be provided for reading the code on the SMD component, which system is not used to detect the position and/or orientation of the SMD component when assembling the circuit.

Furthermore, the method according to the invention preferably provides that the information contained in the read-out code of the SMD component is determined, namely the measured value of the component characteristic and/or the measurement tolerance. This information is then preferably stored in the circuit so that these values can be taken into account when operating the circuit. For technical explanation, it should be noted that the manufacturing process has a relatively inaccurate manufacturing tolerance, so that the component characteristic can exhibit relatively large fluctuations. It is therefore sensible to store the more precise measured value of the component characteristic in the circuit so that the more precise measured value can be taken into account when operating the circuit.

In addition to the inventive method described above, the invention also claims protection for a corresponding SMD component, which is preferably an SMD current measuring resistor. SMD components of this type are known per se from the prior art. It is also known from the prior art to apply a code to such an SMD component, which contains information about a component characteristic of the SMD component. For example, the ElA-96 code (EIA: Electronic Industries Alliance) is used for this in the prior art, which is an alphanumeric code. In contrast, the invention provides that the code consists of several geometric symbols that can be distinguished from alphanumeric characters according to the EIA-96 code.

In a preferred embodiment of the invention, two codes are applied to the SMD component, each consisting of several geometric symbols. For example, the two codes can contain information about different component characteristics of the SMD component.

In the preferred embodiment of the invention, the geometric symbols of the first code are arranged in a first row, while the geometric symbols of the second code are arranged in a second row on the SMD component. The two rows of the two codes preferably run parallel to each other and can be aligned, for example, transversely or longitudinally to the main current flow direction in the SMD component.

In addition, a bar can be arranged on the surface of the SMD component to indicate the length of the respective code, wherein the bar can preferably be aligned parallel to the rows of codes and transversely or longitudinally to the main current flow direction in the SMD component.

With regard to the coding of the information in the code, there are various possibilities within the scope of the invention. For example, the geometric symbols of the code for coding information can have different colors. Alternatively or additionally, it is possible for the geometric symbols for coding information to have different brightnesses. It is also possible for the geometric symbols for coding information to have different shapes. In the simplest case, however, binary coding is used, with a geometric symbol being present (=1) or missing (=0) at one point in the code.

For example, the geometric symbols can be rectangles, circles, triangles or hexagons, to name just a few examples. It is possible that the geometric symbols are consistent within each code. For example, triangles can be used as symbols in one code, while rectangles can be used as symbols in another code.

• • Widerstandswert,
• • Temperaturkoeffizient des Widerstandswerts,
• • Größe des SMD-Bauelements,
• • Masse des SMD-Bauelements,
• • Herstellungsdatum des SMD-Bauelements,
• • Chargennummer des SMD-Bauelements,
• • kundenspezifische Informationen des SMD-Bauelements,
• • Messtoleranz der Bauteilkenngrößen.

In the preferred embodiment of the invention, the information contained in the code is a component characteristic of the SMD component. For example, the following component characteristics can be contained in the code as information:

• • Resistance value,
• • Temperature coefficient of resistance,
• • Size of the SMD component,
• • Mass of the SMD component,
• • Date of manufacture of the SMD component,
• • Batch number of the SMD component,
• • customer-specific information of the SMD component,
• • Measurement tolerance of the component parameters.

However, the invention is not limited to the above-mentioned examples with regard to the coded component characteristic.

In the preferred embodiment of the invention, the SMD component is a low-resistance current measuring resistor with two connection parts made of a conductor material (e.g. copper) for introducing or discharging the electrical current to be measured and a resistance element made of a resistance material (e.g. Manganin®), wherein the resistance element is arranged in the direction of current flow between the two connection parts so that the electrical current to be measured flows through the resistance element.

The above-mentioned code can be applied either to the resistance element or to the connection parts. The current measuring resistor is preferably coated with a protective varnish, with the code then preferably being applied to the protective varnish.

In general, it should be mentioned that the connection parts and the resistance element are preferably plate-shaped, whereby either a flat or a curved plate shape is possible.

Furthermore, it should be noted that the current measuring resistor is preferably low-ohmic and has a resistance value of no more than 1 Ω, 500 mΩ, 250 mΩ, 100 mΩ, 50 mΩ, 25 mΩ, 10 mΩ, 5 mΩ, 1 mΩ, 500 µΩ, 250 µΩ, 100 µΩ, 50 µΩ or 25 µΩ.

The length of the current measuring resistor in the direction of current flow is preferably no more than 5 cm, 2 cm, 1 cm, 5 mm or 3 mm.

The width of the current measuring resistor transverse to the direction of current flow is preferably 5 cm, 2 cm, 1 cm, 5 mm or 3 mm.

The thickness of the current measuring resistor is preferably no more than 5 mm, 3 mm, 2 mm or 1 mm.

Furthermore, it should also be mentioned in general that the code applied to the SMD component is preferably optically readable.

When using a current measuring resistor, it should also be noted that the conductor material of the connecting parts should have a lower specific electrical resistance than the resistance material of the resistance element.

For example, the conductor material of the connection parts can be copper, a copper alloy, aluminum or an aluminum alloy.

The resistance material, on the other hand, can be, for example, a copper-manganese alloy, an iron-nickel-chromium alloy or a nickel-chromium alloy, to name just a few examples.

In general, it should also be mentioned that the conductor material of the connecting parts preferably has a specific electrical resistance that is less than 50·10 ^-8 Ω·m, 20·10 ^-8 Ω·m, 10·10 ^-8 Ω·m or 5·10 ^-8 Ω·m.

Finally, it should be mentioned in general that the current measuring resistor preferably has a continuous current strength of at least 1 A, 2 A, 5 A, 10 A, 25 A, 50 A, 100 A or 400 A.

Other advantageous developments of the invention are characterized in the subclaims or are explained in more detail below together with the description of the preferred embodiment of the invention with reference to the figures.

Short description of the drawings

• 1 shows a flow chart to illustrate the method according to the invention.
• 2 shows a diagram to illustrate the relatively coarse manufacturing tolerance and the relatively precise measuring tolerance of a current measuring resistor according to the invention.
• 3 shows a schematic plan view of an SMD current measuring resistor according to the invention.

Detailed description of the drawings

In the following, the flow chart according to 1 which explains the method according to the invention.

In a first step S1, an SMD current measuring resistor is first manufactured, specifically in this embodiment with a nominal value R _NENN = 1 mΩ of the resistance value R of the SMD current measuring resistor, whereby the manufacturing process requires a certain manufacturing tolerance ±ΔR _FERT of the nominal value R _NENN . It should be mentioned in advance that the manufacturing tolerance ±ΔR _FERT can be relatively inaccurate, since the actual value R _IST of the resistance value R of the SMD current measuring resistor is measured later. This is advantageous because a cost-effective manufacturing process can be used due to the low requirements for the manufacturing tolerance ±ΔR _FERT .

In a subsequent step S2, a measured value R _MEASURE of the resistance value R of the SMD current measuring resistor is then measured with a measurement tolerance ±ΔR _MEASURE , whereby the measurement tolerance ±ΔR _MEASURE is more accurate than the manufacturing tolerance ±ΔR _FERT , as can also be seen from 2 is evident.

In a next step S3, a code is then applied to the SMD current measuring resistor, whereby the code contains the measured value R _MEAS and/or the measuring tolerance ±ΔR _MEAS as information.

It should be noted that steps S1-S3 can be carried out by the manufacturer, i.e. by the manufacturer of the SMD current measuring resistor.

In a step S4, the position and orientation of the SMD current measuring resistor is measured in an assembly line in order to equip a circuit with the SMD current measuring resistor. This measurement of the position and orientation of the SMD current measuring resistor is carried out using an image processing system, as is known from conventional assembly lines.

In the next step S5, the code on the SMD current measuring resistor is then read by the image processing system. It should be emphasized here that the code is read by the image processing system, which is already present in an assembly line in order to measure the position and alignment of the SMD current measuring resistor. A separate image processing system is therefore not required to read the code in step S5.

In a step S6, the position and alignment of the SMD current measuring resistor is then corrected according to the position and alignment determined by the image processing system in order to be able to position the SMD current measuring resistor as precisely as possible in the circuit. The circuit is then also equipped with the SMD current measuring resistor in this step.

In the last step S7, the measured value R _MEASURE of the resistance value R of the SMD current measuring resistor read from the code and the measurement tolerance ±ΔR _MEASURE are stored in the circuit so that these measured values can be taken into account in the operation of the circuit, in particular for calculating the electrical current flowing through the SMD current measuring resistor as a function of the electrical voltage dropping across the SMD current measuring resistor in accordance with the Ohm's law, as explained at the beginning of the well-known four-wire technique.

Steps S4-S7 are usually carried out by the customer when assembling the circuit.

In the following, the diagram is shown according to 2 briefly explained, which shows a relatively large tolerance field 1 of the manufacturing tolerance ±ΔR _FERT of the resistance value R of the SMD current measuring resistor, while a tolerance field 2 shows the measurement tolerance ±ΔR _MESS . From this diagram it can be seen that the tolerance field 2 during measurement is significantly smaller than the tolerance field 1 during manufacture of the SMD current measuring resistor. It is therefore clear that within the scope of the invention a manufacturing process can be used which has a relatively coarse manufacturing tolerance ±ΔR _FERT and nevertheless an accurate determination of the actual resistance value R _IST is possible due to the more precise measurement tolerance ±ΔR _MESS and the small tolerance field 2 during measurement.

Finally, the 3 shown top view of an SMD current measuring resistor according to the invention is explained.

The SMD current measuring resistor has a plate-shaped connection part 3 made of a conductor material (e.g. copper) in order to introduce an electrical current I to be measured into the SMD current measuring resistor.

Furthermore, the SMD current measuring resistor has a plate-shaped connection part 4 made of a conductor material (e.g. copper) in order to lead the electrical current I to be measured out of the SMD current measuring resistor.

A resistance element 5 made of a resistance alloy (e.g. Manganin®) is arranged between the two connection parts 3, 4, wherein the resistance element 5 is welded at its two edges 6, 7 to the plate-shaped connection parts 3, 4 by electron beam welding.

Two codes 8, 9 are applied to the surface of the resistance element 5, each of which contains information about a component characteristic of the SMD current measuring resistor.

The code 8 consists of geometric symbols in the form of triangles 10, while the other code 9 consists of geometric symbols in the form of rectangles 11. The two codes 8, 9 each have six positions (places) that can be occupied by one of the symbols.

The information is binary coded by the presence of a symbol at the respective position (=1) or by a gap 12 or 13 (=0).

The two codes 8, 9 can therefore encode 2 ⁶ = 64 different code words.

mit

V

Anzahl der möglichen Variationen (verschiedene Codewörter),

C

Anzahl der möglichen verschiedenen Farben der geometrischen Symbole,

S

Anzahl der möglichen verschiedenen geometrischen Symbole, wobei eine Lücke auch ein Symbol ist,

P

Anzahl der Stellen innerhalb eines Codewortes.

However, it is also possible to vary the color of the symbols. Furthermore, different geometric symbols can be used to encode information. The number of variations V is then calculated as follows: $$V={\left[1+C\cdot \left(S-1\right)\right]}^P$$

with

V

Number of possible variations (different code words),

C

Number of possible different colors of the geometric symbols,

S

Number of possible different geometric symbols, where a gap is also a symbol,

P

Number of digits within a code word.

Furthermore, the top view also shows a bar 14, which has two functions. Firstly, the bar 14 shows the length of the two codes 8, 9. This makes it easier to read the two codes 8, 9 using an optical image processing system. Secondly, the bar 14 also serves as an alignment aid for aligning the SMD current measuring resistor when fitting the circuit with the SMD current measuring resistor.

Finally, the top view shows that the SMD current measuring resistor can have a length L along the current flow direction and a width B perpendicular to the current flow direction.

The invention is not limited to the preferred embodiment described above. Rather, a large number of variants and modifications are possible which also make use of the inventive concept and therefore fall within the scope of protection. In particular, the invention also claims protection for the subject matter and the features of the subclaims independently of the respective claims referred to and in particular also without the features of the main claim. The invention therefore comprises various aspects of the invention which are protected independently of one another.

List of reference symbols:

1

Tolerance range of resistance value R during production

2

Tolerance field when measuring the resistance value

3

Connection part made of a conductor material (e.g. copper) for introducing the electrical current to be measured into the SMD current measuring resistor

4

Connection part made of a conductor material (e.g. copper) for conducting the electrical current to be measured from the SMD current measuring resistor

5

Resistance element made of a resistance material (e.g. Manganin®)

6

Edge of the resistance element

7

Edge of the resistance element

8

code

9

code

10

Triangles as code symbols of Code 8

11

Rectangles as code symbols of Code 9

12

Gaps as code symbols in the Code 8

13

Gaps as code symbols in Code 9

14

beam

I

Current to be measured

R

Resistance value of the SMD current measuring resistor

RNOMINAL

Nominal resistance value of SMD current measuring resistor

±ΔRFERT

Manufacturing tolerance of the resistance value of the SMD current measuring resistor

RISP

Actual value of the resistance of the SMD current measuring resistor

RMAX

Maximum resistance value of the SMD current measuring resistor

RMIN

Minimum resistance value of the SMD current measuring resistor

RMESS

Measured resistance value of SMD current measuring resistor

±ΔRMEASURE

Measurement tolerance of the resistance value of the SMD current measuring resistor

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• EP 0605800 A1 [0002]

Claims (14)

Method for providing an SMD component, in particular an SMD current measuring resistor, with the following steps: a) producing the SMD component with a predetermined nominal value (R _NENN ) of a component characteristic of the SMD component and a certain manufacturing tolerance (±ΔR _FERT ) of the component characteristic (R), b) measuring a measured value (R _MESS ) of the component characteristic of the SMD component with a certain measuring tolerance (±ΔR _MESS ), wherein the measuring tolerance (±ΔR _MESS ) is more precise than the manufacturing tolerance (±ΔR _FERT ), and c) applying a code (8, 9) to the SMD component, wherein the code (8, 9) contains information about the measured measured value (R _MESS ) of the component characteristic (R) of the SMD component and/or the measuring tolerance (±ΔR _MESS ). Procedure according to Claim 1 , characterized by the following steps for equipping a circuit with the SMD component: a) detecting the position and/or orientation of the SMD component by means of an optical image processing system, b) correcting the position and/or orientation of the SMD component according to the position and/or orientation of the SMD component determined by the image processing system, and c) equipping the circuit with the SMD component after correcting the position and/or orientation of the SMD component. Procedure according to Claim 2 , characterized by the following step when equipping the circuit with the SMD component: a) reading the code (8, 9) on the SMD component by means of the image processing system, which also serves to detect the position and/or the orientation of the SMD component when equipping the circuit, or b) reading the code (8, 9) on the SMD component by means of a separate image processing system which does not serve to detect the position and/or the orientation of the SMD component when equipping the circuit. Procedure according to Claim 3 , characterized by the following step: a) determining the measured value (R _MESS ) of the component characteristic (R) and/or the measurement tolerance (±ΔR _MESS ) from the read code (8, 9), and/or b) storing the measured value (R _MESS ) of the component characteristic (8, 9) and/or the measurement tolerance (±ΔR _MES ) in the circuit for consideration when operating the circuit. SMD component, in particular SMD current measuring resistor, with a) a first code (8) applied to the SMD component, wherein the first code (8) contains information about a first measured value (R _MEASURE ) of a first component characteristic (R) of the SMD component and/or a first measurement tolerance (±ΔR _MEASURE ) with which the first measured value (R _MEASURE ) was measured, characterized in that b) the first code (8) consists of several geometric symbols (10, 12). SMD component according to Claim 5 , characterized by a second code (9) applied to the SMD component, wherein the second code (9) consists of several geometric symbols (11, 13) and contains information about a second measured value of a second component characteristic of the SMD component and/or a second measurement tolerance with which the second measured value was measured. SMD component according to Claim 6 , characterized in that a) the geometric symbols (10, 12) of the first code (8) are arranged on the SMD component in a first row, and/or b) the geometric symbols (11, 13) of the second code (9) are arranged on the SMD component in a second row, and/or c) the first row of the first code (8) and the second row of the second code (9) are arranged parallel to one another on the SMD component, and/or d) the first row of the first code (8) is aligned transversely and/or longitudinally to the main current flow direction in the SMD component, and/or e) the second row of the second code (9) is aligned transversely and/or longitudinally to the main current flow direction in the SMD component, and/or f) a bar (14) is arranged on the surface of the SMD component in order to determine the length of the first code (8) and/or the second code (9). and/or g) that the bar (14) is aligned parallel to the first line of the first code (8) and/or parallel to the second line of the second code (9) and/or transversely and/or longitudinally to the main current flow direction in the SMD component. SMD component according to one of the Claims 5 until 7 , characterized in that a) the geometric symbols (10, 11, 12, 13) for coding the first or second component characteristic have different colors, and/or b) the geometric symbols (10, 11, 12, 13) for coding the first or second component characteristic have different brightnesses, and/or c) the geometric symbols (10, 11, 12, 13) for coding the first or second component characteristic have different shapes. SMD component according to one of the Claims 5 until 8 , characterized in that the geometric symbols comprise at least one of the following symbols: a) rectangle (11), b) circles, c) triangle (10), d) gap (12, 13) or e) hexagon. SMD component according to one of the Claims 5 until 9 , characterized in that a) the geometric symbols (10, 12) in the first code (8) are uniform, and/or b) the geometric symbols (11, 13) in the second code (9) are uniform, and/or c) the geometric symbols (10, 12) in the first code (8) are different geometric symbols than in the second code (9), or d) different symbols in a code line are assigned to a code, and/or e) the symbols (10, 11, 12, 13) have the same color, and/or f) the symbols (10, 11, 12, 13) have different colors, and/or g) the color of the symbols (10, 11, 12, 13) has the same brightness, and/or h) the color of the symbols (10, 11, 12, 13) has a different brightness. SMD component according to one of the Claims 5 until 10 , characterized in that the information contained in the first code (8) and/or the information contained in the second code (9) represents at least one of the following component characteristics of the SMD component: a) resistance value (R _MEASURE ), b) temperature coefficient of the resistance value, c) size of the SMD component, d) mass of the SMD component, e) date of manufacture of the SMD component, f) batch number of the SMD component, g) customer-specific information of the SMD component, h) measurement tolerance (±ΔR _MEASURE ) of the component characteristics. SMD component according to one of the Claims 5 until 11 , characterized by a design as a current measuring resistor with a) a first connection part (3) made of a conductor material for introducing an electrical current (I) to be measured into the current measuring resistor, b) a second connection part (4) made of a conductor material for conducting the electrical current (I) to be measured out of the current measuring resistor, and c) a resistance element (5) made of a resistance material, wherein the resistance element (5) is arranged in the current flow direction between the first connection part (3) and the second connection part (4), so that the electrical current (I) to be measured flows through the resistance element (5). SMD component according to Claim 12 , characterized in that a) the first code (8) is applied to the resistance element (5) of the current measuring resistor, and/or b) the second code (9) is applied to the resistance element (5) of the current measuring resistor, or c) the first code (8) is applied to the protective varnish of the current measuring resistor, and/or d) the second code (9) is applied to the protective varnish of the current measuring resistor, or e) the first code (8) is applied to a connection part (3, 4) of the current measuring resistor, and/or f) the second code (9) is applied to a connection part (3, 4) of the current measuring resistor. SMD component according to one of the Claims 12 until 13 , characterized in that a) the first connection part (3), the second connection part (4) and/or the resistance element (5) is plate-shaped, and/or b) the current measuring resistor has a resistance value of at most 1 Ω, 500 mΩ, 250 mΩ, 100 mΩ, 50 mΩ, 25 mΩ, 10 mΩ, 5 mΩ, 1 mΩ, 500 µΩ, 250 µΩ, 100 µΩ, 50 µΩ or 25 µΩ, and/or c) the current measuring resistor has a length (L) of at most 5 cm, 2 cm, 1 cm, 5 mm or 3 mm in the direction of current flow, and/or d) the current measuring resistor has a width (B) of at most 5 cm, 2 cm, 1 cm, 5 mm or 3 mm, and/or e) that the current measuring resistor has a thickness of at most 5 mm, 3 mm, 2 mm or 1 mm, and/or f) that the first code (8) and/or the second code (9) is optically readable, and/or g) that the conductor material of the connection parts (3, 4) has a lower specific electrical resistance than the resistance material of the resistance element (5), and/or h) that the conductor material of the connection parts (3, 4) is copper, a copper alloy, aluminium or an aluminium alloy, and/or i) that the conductor material of the connection parts (3, 4) has a specific electrical resistance which is less than 50·10 ^-8 Ω·m, 20·10 ⁸ Ω·m, 10·10 ^-8 Ω·m or 5·10 ^-8 Ω·m, and/or j) that the current measuring resistor has a continuous current strength of at least 1A, 2A, 5A, 10A, 25A, 50A, 100A or 400A, and/or k) that the resistance material of the resistance element is one of the following alloys: k1) copper-manganese alloy, in particular copper-manganese-nickel alloy, k2) iron-nickel-chromium alloy, k3) nickel-chromium alloy.

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