CN102096058A - Method and device for verifying high-accuracy direct-current comparator - Google Patents

Abstract

The invention provides a method and device for verifying a high-accuracy direct-current comparator for resistance measurement. The method comprises the following steps: firstly connecting two or more than two same nominal resistors in serial and in parallel so as to respectively form serial resistor arrays and parallel resistor arrays; connecting the parallel resistor arrays with nodes at the two ends of all parallel resistors by virtue of a four-end lead node structure, and setting short-circuit compensation for externally-connected short-circuit sheets when the resistor arrays are connected in parallel; then carrying out proportion measurement by virtue of measured direct-current comparators, and obtaining serial-parallel proportion readings by the direct-current comparators; connecting three groups or more than three groups of nominal resistors in series and in parallel, and then carrying out the proportion measurement by virtue of the measured direct-current comparators; and comparing with the specified accuracy level according to the production of the serial-parallel proportion readings of all the groups of serial and parallel resistor arrays, so as to realize the proportion verification of the direct-current comparators. By utilizing the method provided by the invention, accurate verification of proportional errors of the high-accuracy (the accuracy reaches 10-7-10-8 levels) direct-current comparator used for resistance measurement can be realized.

Description

The verification method and the device of pin-point accuracy DC current comparator

Technical field

The present invention relates to a kind of Electric Measurement Technology, particularly a kind of verification method and device that is used for the pin-point accuracy DC current comparator of resistance measurement.

Background technology

The appearance of current comparator is the impressive progress that the electrical measurement in modern age has milestone significance, has solved the difficult problem of voltage, electric current, resistance and the contour accuracy measurement of power electric energy in succession.Along with developing by leaps and bounds of electronic technology, servo power supply that trace performance is good and sensitive magnetic flux detecting device are developed in succession, and the appearance of high magnetic permeability material, for developing accuracy up to 10 ^-8The current comparator of the order of magnitude has been created necessary condition.

The DC current comparator is made up of iron core and coil, and for the DC current comparator, its structural representation on the iron core of a bracelet annular high magnetic permeability, carries out current ratio winding W around last two respectively as shown in Figure 1 ₁, W ₂With a detection winding W _DAs two comparison winding W ₁And W ₂In when feeding DC current because the residue magnetic potential is a direct current, in iron core C, can only produce direct current flux, so detect winding W _DIn can not induce electromotive force.In order to carry out the comparison between two DC current, just in order to detect whether there is direct current flux in the iron core, need to adopt the magnetic modulation technique, introduce and exchange exciting curent, and by detect iron core reach capacity the time in advance or postpone to determine whether to exist direct current residue magnetic potential Δ (IW), or by detecting winding W _DThe detection of the interior two frequency multiplication voltages that occur determines whether to exist direct current residue magnetic potential Δ (IW).Because its measurement result is only relevant with the turn ratio of coil, so linear characteristic is good, easy to use, purposes is wide, but mostly programmed control at present can realize all automatic measurement.But because not coupling fully between the ratio coil of two windings of this DC current comparator so there is leakage flux, if these leakage fluxs also have coupling with the device that detects ampere-turn equilibrium, has just caused the error of current ratio; In addition, the DC current comparator is to utilize the nonlinear characteristic of ferromagnetic material to monitor the ampere turns equilibrium state, and detection sensitivity also can be introduced error.

For solving the problem that above-mentioned error is brought, adopt two kinds of method: a usually, adopt high permeability material that the coil and the ratio coil that detect winding are kept apart, reduce the coupling between leakage flux and the magnetic test coil as far as possible; B, employing method of calibration are determined ratio error.Because method a is subjected to the restriction of real material property, especially for accuracy up to 10 ^-8The current comparator of the order of magnitude, it is very limited to improve room for improvement, so the ratio error of normal employing method b research calibration or checking normal temperature current comparator.

The ratio range of the current comparator of pin-point accuracy was generally 1: 1,10: 1, measurement range generally is 1 Ω-1000 Ω, therefore the demo plant of this dc comparator need be verified 1: 1 ratio of 1 Ω-1000 Ω range, 1k Ω: 100 Ω, 100 Ω: 10 Ω, 10 Ω: 10: 1 ratios of ranges such as 1 Ω, proportional error is generally 10 ^-7-10 ^-8Magnitude.

(accuracy reaches 10 to be used for the pin-point accuracy of resistance measurement ^-7-10 ^-8Magnitude) when in parallel, the parallel resistance resistance is approximately equal to the relative deviation of series connection resistance for nR for the relative deviation of R/n with the nominal value resistance R for DC current comparator, n.The consistent degree of this n resistance is the key factor of influence resistance relative deviation in parallel and series connection resistance relative deviation consistance degree of approximation.

Below be the mathematical derivation process:

Suppose that n resistance nominal value is R, actual value is R ₁, R ₂... R _n, their arithmetic mean value is R ₀, R ₁=R ₀(1+C ₁), R ₂=R ₀(1+C ₂) ... R _n=R ₀(1+C _n), C _iBe the relative deviation of i resistance, and have

$\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{C}_i=0$

Then the resistance in series actual resistance is R _s=nR ₀

By the nominal value resistance of then connecting is nR, and establishing series connection resistance relative deviation is C _s, therefore such one group of relation is arranged:

R _s＝n·R(1+C _s)--------------------------------①

Resistance R in parallel _p, equation is as follows:

$\frac{1}{R_p}=\frac{1}{R_0(1+C_1)}+\frac{1}{R_0(1+C_2)}+\·\·\·\·\·\·+\frac{1}{R_0(1+C_n)}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\frac{1}{R_0(1+C_i)}$

C _iBe generally value, do series expansion, omit three rank and above a small amount of, obtain less than 0.01%:

$\frac{1}{R_p}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\frac{1}{R_0(1+C_i)}\≈\frac{1}{R_0}(n-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{C}_i+\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{C}_i^2)=\frac{n}{R_0}(1+\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{C}_i^2)$ --------------②

If select C _iFor less than 0.01% resistance, then

Less than 10 ^-8, can omit and disregard, 2. the formula abbreviation is $\frac{1}{R_p}=\frac{n}{R_0},$

Therefore, R _s=n ²R _p----------------------------------------3.

By nominal value resistance then in parallel be

If resistance relative deviation in parallel is C _p, therefore such one group of relation is arranged:

$R_p=\frac{R}{n}(1+C_p)$ ------------------------------------④

Will be 1. and 4. substitution 3. obtain at last:

C _s＝C _p----------------------------------------------⑤

5. expression formula illustrates at the relative deviation of ignoring the series connection resistance of n resistance under the high-order a small amount of situation and equals resistance relative deviation in parallel.

The consistance of the consistent degree of n resistance and its series and parallel resistance relative deviation be " square " relation, therefore by select consistent degree preferably one group of resistance R can obtain high connection in series-parallel resistance consistance, usually can think that the relative deviation of the resistance in parallel of n resistance R equals the relative deviation of these resistance series connection resistances.

Verify that the difficulty that proportional error ran into of pin-point accuracy DC current comparator is if adopt above principle:

1, owing to only has n between the above connection in series-parallel resistance error ²: 1 propagation of error relation, see formula 3., n is a natural number, so can't directly realize error checking in 10: 1.

2, because the concrete resistance that needs to verify is 10 Ω: 1 Ω, 100 Ω: 10 Ω, 1k Ω: 100 Ω, and the checking accuracy need reach 10 ^-7-10 ^-8Magnitude.Because copper wire resistivity is about 1.8 * 10 ^-8Ω m, so diameter 1mm, the copper wire resistance of long 1cm is about 1.8 * 10 ^-4Ω is therefore for 1 Ω, if the error of the lead resistance of checking accuracy requirement is less than 10 ^-7-10 ^-8Magnitude is equivalent to the wire length error less than 10 μ m, and this is that technical being difficult to reaches.The relation of deriving above all is to suppose in ideal conditions, the resistance of tie point is under zero the situation, in actual conditions, resistance is connected to the lead resistance of terminal and the measurement result that short circuit resistance in parallel will directly have influence on institute's contrive equipment, therefore above formula of deriving can not directly use in the reality, need the particular design improvement of adopting an effective measure.

3, can not directly verify 1: 1 proportional error.

(accuracy reaches 10 at the pin-point accuracy that is used for resistance measurement ^-7-10 ^-8Magnitude) checking of DC current comparator, the present domestic demo plant that is exclusively used in this quasi-instrument proportional error of calibration that still do not have, and external employing cryo-current comparator demo plant is verified, the cost of this device is very high, and proof procedure and data processing are quite loaded down with trivial details.

Summary of the invention

The present invention is directed to the defective or the deficiency that exist in the prior art, a kind of verification method of pin-point accuracy DC current comparator is provided, this method can overcome in the prior art because the direct difficulty that proportional error ran into of checking pin-point accuracy DC current comparator, realizes being used for the accurate checking of proportional error of the pin-point accuracy DC current comparator of resistance measurement.The invention still further relates to a kind of demo plant that is used for the pin-point accuracy DC current comparator of resistance measurement.

Technical scheme of the present invention is as follows:

A kind of verification method that is used for the pin-point accuracy DC current comparator of resistance measurement, the accuracy of described DC current comparator is 10 ^-7-10 ^-8Magnitude, it is characterized in that, at first make it constitute resistance in series array and parallel resistance array respectively with the nominal resistance connection in series-parallel two or more, described parallel resistance array adopts four end pin node structures to connect each parallel resistance two end node, and for electric resistance array when in parallel external short-circuit piece the short circuit compensation is set, described short circuit compensation is included in potential compensation resistance that is provided with between each resistance and its external current potential short-circuit piece in parallel and the current compensation resistance that is provided with between each resistance and its external current parallel short-circuit piece, the magnitude of the relative error of described potential compensation resistance and current compensation resistance is 10 ^-2-10 ^-3, four end pin node by regular hexahedron between described potential compensation resistance and current compensation resistance and the electric resistance array connect, and described four end pin node are how much and are symmetrical arranged on regular hexahedron; Do proportion measurement by tested dc comparator then, dc comparator draws connection in series-parallel ratio registration respectively; Adopt the above nominal resistance connection in series-parallel of three groups or three groups after tested dc comparator is done proportion measurement, nominal resistance number on the same group is not identical, the nominal value difference, according to the product of the connection in series-parallel ratio registration of each group connection in series-parallel electric resistance array respectively with the comparison of the accuracy magnitude of regulation, realize the ratio checking of this DC current comparator.

Adopt three groups of resistance string parallel connected arrays, the same normal resistance of each group is respectively 100 Ω, 10 Ω and 1k Ω, each number of organizing nominal resistance is 10, for 100 Ω normal resistances, described proportion measurement comprises that dc comparator is 1k Ω at range: 100 Ω, 100 Ω: 10 Ω and 10 Ω: 10: 1 the proportion measurement of 1 Ω; For 10 Ω normal resistances, described proportion measurement comprises that dc comparator is 10: 1 the proportion measurement of 100 Ω-10 Ω at range; For 1k Ω normal resistance, described proportion measurement comprises that dc comparator is 10: 1 the proportion measurement of 10k Ω-100 Ω at range; Be meant according to the product of the connection in series-parallel ratio registration of each group connection in series-parallel electric resistance array and the more specific of accuracy magnitude of regulation: when the product of the connection in series-parallel ratio registration of three groups of connection in series-parallel electric resistance arrays all meets 10 ^-7-10 ^-8During magnitude, determine that this current comparator proportion measurement is correct; When three groups of products have only nominal resistance is 100 Ω when exceeding standard, and verifies out that error appears in the whole ranges of current comparator; When three groups of products have only nominal resistance is 10 Ω or 1k Ω when exceeding standard, and verifies out that current comparator other ranges beyond this proportion measurement measured that exceeds standard are normal; The residue situation verifies out that all proportional error appears in current comparator.

Comprise also aligning the symmetric levelling of hexahedral four end pin node that described levelling comprises that the resistance part less than normal between two nodes that align in the hexahedral four end pin node exchanges views levelling by a small margin.

Described regular hexahedron is determined size by finish-milling and line cutting processing and according to nominal resistance, and described regular hexahedron rib is long to be 5mm～10mm.

On the lead-in wire circuit except that each resistance that four end pin node connect, be provided with respectively potential compensation resistance (A) and current compensation resistance (B, B＜＜A), the maximum relative error that passes through the circuit of Compensation Design is

Wherein, α _MaxBe max value of error in the potential compensation resistance, β _MaxBe max value of error in the current compensation resistance.

A kind of demo plant that is used for the pin-point accuracy DC current comparator of resistance measurement is used for accuracy 10 ^-7-10 ^-8The checking of the DC current comparator of magnitude, it is characterized in that, comprise three groups or three groups of above connection in series-parallel electric resistance arrays, also comprise compensating circuit and authentication unit, described connection in series-parallel electric resistance array resistance in series array and the parallel resistance array that two or more constitute respectively with the nominal resistance connection in series-parallel of serving as reasons, nominal resistance number on the same group is not identical, the nominal value difference, described parallel resistance array connects compensating circuit, described compensating circuit with electric resistance array when in parallel external short-circuit piece the short circuit compensation is set, described compensating circuit be included in the current potential short-circuit piece in parallel that is provided with between each resistance and its external current potential short-circuit piece in parallel potential compensation resistance and and the current compensation resistance that between each resistance and its external current parallel short-circuit piece, is provided with, the magnitude of the relative error of described potential compensation resistance and current compensation resistance is 10 ^-2-10 ^-3, four end pin node by regular hexahedron between described potential compensation resistance and current compensation resistance and the electric resistance array connect, and described four end pin node are how much and are symmetrical arranged on regular hexahedron; Compensating circuit links to each other with tested dc comparator, draws connection in series-parallel ratio registration respectively thereby do proportion measurement by tested dc comparator; Described authentication unit according to the product of the connection in series-parallel ratio registration of each group connection in series-parallel electric resistance array respectively with the comparison of the accuracy magnitude of regulation, realize the ratio checking of this DC current comparator.

Also comprise the levelling circuit, described levelling circuit comprise and four end pin node in two nodes between the current source that is provided with and and two other node between the open-circuit voltage that is provided with, described levelling circuit is used to align the symmetric levelling of hexahedral four end pin node, and described levelling comprises exchanges views levelling by a small margin to the part less than normal of the resistance between two nodes.

Described connection in series-parallel electric resistance array comprises three groups, the same normal resistance of each group is respectively 100 Ω, 10 Ω and 1k Ω, each number of organizing nominal resistance is 10, for 100 Ω normal resistances, described proportion measurement comprises that dc comparator is 1k Ω at range: 100 Ω, 100 Ω: 10 Ω and 10 Ω: 10: 1 the proportion measurement of 1 Ω; For 10 Ω normal resistances, described proportion measurement comprises that dc comparator is 10: 1 the proportion measurement of 100 Ω-10 Ω at range; For 1k Ω normal resistance, described proportion measurement comprises that dc comparator is 10: 1 the proportion measurement of 10k Ω-100 Ω at range; When the product of the connection in series-parallel ratio registration of three groups of connection in series-parallel electric resistance arrays all meets 10 ^-7-10 ^-8During magnitude, described authentication unit determines that this current comparator proportion measurement is correct; When three groups of products have only nominal resistance is 100 Ω when exceeding standard, and described authentication unit verifies out that error appears in the whole ranges of current comparator; When three groups of products have only nominal resistance is 10 Ω or 1k Ω when exceeding standard, and described authentication unit verifies out that current comparator other ranges beyond this proportion measurement measured that exceeds standard are normal; The described authentication unit of residue situation verifies out that all proportional error appears in current comparator.

Described regular hexahedron forms by finish-milling and line cutting processing and determines size according to nominal resistance, and described regular hexahedron rib is long to be 5mm～10mm.

On the lead-in wire circuit except that each resistance that four end pin node connect, be provided with respectively in the described compensating circuit potential compensation resistance (A) and current compensation resistance (B, B＜＜A), the maximum relative error after compensating circuit compensates is

Wherein, α _MaxBe max value of error in the potential compensation resistance, β _MaxBe max value of error in the current compensation resistance.

Technique effect of the present invention is as follows:

The verification method of the pin-point accuracy DC current comparator that is used for resistance measurement that the present invention relates to, make it constitute resistance in series array and parallel resistance array respectively with the nominal resistance connection in series-parallel two or more, connect each parallel resistance two end node by the four end pin node structures that adopt in the parallel resistance array, and for electric resistance array when in parallel external short-circuit piece the short circuit compensation is set, and four end pin node by regular hexahedron between the resistance of short circuit compensation and the parallel resistance array connect, because four end pin node are set, when electric current is flowed through any 2 the time, there is not significant voltage drop between all the other 2, and this four ends lead-in wire has been avoided the lead resistance interference all being symmetrically on the geometric configuration and on electric property.Electric resistance array needs external short-circuit piece when becoming parallel connection, because there is resistance in short-circuit piece itself, and the distribution of short-circuit piece is difficult to control, if without compensation, can cause the parallel resistance mismatch, will cause very big error, can utilize the mode of compensation to eliminate and reduce these errors by short circuit in parallel compensation is set, and make that node-resistance evenly equates between any 2, and overcome the error that causes thus, make the checking accuracy reach 10 ^-7-10 ^-8Magnitude, thus the ratio that realizes pin-point accuracy DC current comparator is verified.Do proportion measurement by tested dc comparator, dc comparator draws connection in series-parallel ratio registration respectively, adopt the above resistance string of three groups or three groups in parallel after tested dc comparator is done proportion measurement, then according to the product of the connection in series-parallel ratio registration of each group connection in series-parallel electric resistance array respectively with the comparison of the accuracy magnitude of regulation, realize the ratio checking of current comparator, this verification method can directly be verified the measurement of the proportional error of pin-point accuracy dc comparator in the range of regulation, need not the cryo-current comparator demo plant that adopts cost high, in actual applications proof procedure and data processing are simple, and have reduced the checking cost.

By aligning the symmetric levelling of hexahedral four end pin node, described levelling comprises that the part less than normal of the resistance between two nodes that align hexahedral four end pin node exchanges views levelling by a small margin, by exchanging views levelling by a small margin, increase its resistance, make each node symmetrically, overcome the inhomogeneous error that causes of four end pin node; Process regular hexahedron by the finish-milling mode, technology is simple, is convenient to realize that the pin node size will be determined size according to the actual nominal resistance, and the regular hexahedron diameter range is 5mm～10mm, and little resistance needs bigger.

The demo plant of the pin-point accuracy DC current comparator that is used for resistance measurement that the present invention relates to, comprise three groups or three groups of above connection in series-parallel electric resistance arrays, also comprise compensating circuit and authentication unit, connect compensating circuit by parallel resistance array at the connection in series-parallel electric resistance array, and will connect by four end pin node connection methods between compensating resistance in the compensating circuit and the electric resistance array, can overcome on the short-circuit piece because the inhomogeneous correction error that causes of resistance, guaranteed the symmetry of four end pin node simultaneously, and any two lead-in wire intermediate node resistance are evenly equal, and 10 ^-7-10 ^-8Magnitude.Compensating circuit links to each other with tested dc comparator, thereby do proportion measurement by tested dc comparator and draw connection in series-parallel ratio registration respectively, and by authentication unit according to the product of the connection in series-parallel ratio registration of each group connection in series-parallel electric resistance array respectively with the comparison of the accuracy magnitude of regulation, realize the ratio checking of pin-point accuracy current comparator.

Description of drawings

Fig. 1 is the structural representation of DC current comparator.

Fig. 2 is used for the process flow diagram of verification method of the pin-point accuracy DC current comparator of resistance measurement for the present invention.

Fig. 3 is four leads method schematic diagrams.

Fig. 4 is the present invention's four end node structural representations.

Fig. 5 is levelling metering circuit structural representation.

The resistance in series array that Fig. 6 constitutes with nominal resistance series connection back for the present invention.

Fig. 7 connects and without the parallel resistance pattern of circuit compensation without four end pin node.

The parallel resistance array that Fig. 8 constitutes after with the nominal resistance parallel connection for the present invention.

Fig. 9 is used for the demo plant preferred structure synoptic diagram of the pin-point accuracy DC current comparator of resistance measurement for the present invention.

Embodiment

The present invention will be described below in conjunction with accompanying drawing.

Fig. 2 is used for the process flow diagram of verification method of the pin-point accuracy DC current comparator of resistance measurement for the present invention.At first (resistance is R with ten same nominal resistances _A) connection in series-parallel makes it constitute resistance in series array and parallel resistance array respectively, described parallel resistance array adopt four end pin node structures to connect each parallel resistance two end node and with electric resistance array when in parallel external short-circuit piece the short circuit compensation is set, do proportion measurement by tested dc comparator then, dc comparator draws connection in series-parallel ratio registration respectively; Adopting the above resistance string of three groups or three groups, in parallel nominal resistance number on the same group all is not ten after tested dc comparator is done proportion measurement, and nominal value difference, the resistance of nominal resistance as shown in Figure 2 are R _A... R _I, according to the product of the connection in series-parallel ratio registration of each group connection in series-parallel electric resistance array respectively with the comparison of the accuracy magnitude of regulation, realize the ratio checking of current comparator.

Because each nominal resistance has lead-in wire, and to rely on the mode of contact to be connected in the measuring process with other surveying instrument, therefore for the measurement of pin-point accuracy, resistance lead and contact resistance all can cause the resistance measurement error, in order to eliminate the influence of lead-in wire and contact resistance, four leads method are all taked in pin-point accuracy measurement for middle low resistance, and four leads method schematic diagrams as shown in Figure 3.I among Fig. 3 ₁, I ₂Be to connect current terminal, be called current feed, V ₁, V ₂Connect A ', B ' voltage measurement end respectively, be called voltage lead.During turn-on current, voltage lead is the voltage measurement end, does not have electric current to pass through, so V ₁, V ₂Respectively with A ', B ' equipotential, therefore no matter how long current feed and voltage lead have, the lead-in wire self-resistance can not added A ', the B ' point-to-point transmission of measured resistance during measurement, therefore take four leads method measuring resistances can eliminate the influence of current feed resistance, and can overcome the error that contact resistance causes, so the measuring resistance of pin-point accuracy is all made four line caps, four lines easy to use connect.

Used components and parts in the verification method that the present invention relates to all adopt four-wire ohm, so all jointings all should be four end connectors, and the intersection of its tie point and adjacent node resistance should be zero or minimum as far as possible.The such node that respectively installs that is used for the verification method of pin-point accuracy dc comparator of the present invention can not be common welding node, needs special processing.In the present invention, the meaning of four end pin node is: when electric current any two points of flowing through, all the other point-to-point transmissions should not have significant voltage drop.Such node should be enough big, is convenient to operation when processing and wiring.The node that satisfies this requirement should be symmetrical fully on geometric configuration, thereby also is symmetrical on electric property.The node structure that meets this requirement can be the spheroidal node, and four ends lead-in wire is a central point with the centre of sphere, how much upward complete symmetries between extended four lead-in wires in positive tetrahedron summit.But because sphere nodes is difficult to processing, and be difficult to carry out the resnstance transformer levelling, even holosymmetric sphere nodes design proposal also must just can make node-resistance reach on the electric property symmetrically through levelling, so sphere is not a best design in actual use.

Therefore the present invention proposes the design of regular hexahedron shape four end pin node on experiment basis, and the actual measurement node-resistance reaches 10 ^-9-10 ^-8Ω magnitude, described four end pin node are four end points of regular hexahedron, and described four end points all are symmetrical arranged two end points on each face of regular hexahedron, as shown in Figure 4.Among the figure, 1 ', 2 ', 3 ', 4 ' represents four lead-in wires, and middle cube is the solid that metal material (brass) is made, and locates to leave to be convenient to the wire bonds aperture on 4 summits.Square build structural symmetry height, the intersection diagonal line end points on two opposites has four, and 1 '-2 ', 1 '-4 ', 1 '-3 ', 2 '-4 ', 2 '-3 ', 3 '-4 ' between any two symmetric relation all is identical among the last figure, so satisfies uniformity requirement.Aspect processing, can take modes such as finish-milling and line cutting processing, be convenient to relatively realize.Four ends lead-in wire economize on electricity size will be determined size according to actual resistance, general 5mm * 5mm * 5mm～10mm * 10mm * 10mm, and little resistance needs greater.

This verification method also relates to the levelling that aligns hexahedral four end pin node: even in design with add the symmetry that has guaranteed four end pin node man-hour as far as possible, but four end pin node are still because all microscopic reasons are even inadequately in the practical application, cause error, therefore need levelling.Its levelling measurement structure synoptic diagram as shown in Figure 5.Use the electric current (specifically using size of current to decide according to node size) of 5-10 ampere to flow into from terminal A end, flow out from B, C, D terminated line respectively, the never alive other two ends of open-circuit voltage are measured.As in A, C two ends turn-on current, then may have small voltage generally speaking between B, D occurs, if the B point voltage is higher than the D point, the symmetry of this explanation node is short of to some extent, and resistance is little between B and A, resistance is big between B and C, therefore need levelling, the method for levelling is carried out rasion by a small margin with file exactly between A, B, increases the resistance between A and B, make 2 open-circuit voltages of B, D less than 0.05 μ V, this just is equivalent to, and resistance is 5 * 10 between B, D ^-9-10 ^-8Ω.Therefore node can not be done too greatly, in order to avoid polishing expends man-hour.Carry out according to above steps in sequence, BC, BD, CD are through after the levelling, and four pin node just meet application requirements of the present invention.

In this verification method, (resistance is R with ten same nominal resistances ₁) connection in series-parallel makes it constitute resistance in series array and parallel resistance array respectively, its resistance in series array as shown in Figure 6, the parallel resistance array is as shown in Figure 8.According to the connection in series-parallel ultimate principle, the ratio of series connection and state in parallel is 100: 1 that fix, and manufactures 10 * 100 Ω respectively, and 10 * 10 Ω, three electric resistance arrays of 10 * 1k Ω just can be used for current comparator is verified that the checking accuracy need reach 10 ^-7-10 ^-8Magnitude.

If directly with external short-circuit piece I with 1,3 among Fig. 6,5,7,9,11 short circuits use short-circuit piece II with 2,4, and 6,8,10 short circuits form connecting and without the paralleling model of this 10 resistance of circuit compensation, for pin-point accuracy ratio checking (10 without four end pin node as shown in Figure 7 ^-7-10 ^-8Magnitude), because short-circuit piece I in parallel and II self also have certain small resistor (10 ^-3-10 ^-4Magnitude), and the distributed resistance of short-circuit piece is restive, and this can cause the electric resistance array mismatch, and this can cause error in parallel, can not satisfy 10 ^-7-10 ^-8The ratio checking of magnitude.

The present invention takes the method for electric current current potential double compensation to solve this problem, the compensating resistance that adds specific resistance respectively on the current potential lead of electric resistance array or current lead is with round-off error exactly, and the resistance and the error size of these compensating resistances draw by accurate Calculation.Through the overall work circuit of Compensation Design practical application as shown in Figure 8, i.e. parallel resistance array.Wherein square black square is represented four end pin node, and symbol I-1 is a current parallel short-circuit piece 1 among the figure, and V-1 is a current potential short-circuit piece 1 in parallel, and I-2 is a current parallel short-circuit piece 2, and V-2 is a current potential short-circuit piece 2 in parallel.

R is with the nominal operation resistance, γ 1 is the relative deviation of the 1st operating resistance, and γ 2 waits.

A is for connecting the potential compensation resistance of current potential short-circuit piece in parallel, and wherein the 1st and the last compensating resistance resistance are 2A, α 1 is the 1st a potential compensation resistance relative deviation, and α 2 waits.

B is for connecting the current compensation resistance of current parallel short-circuit piece, and wherein the 1st and the last compensating resistance resistance are 2B, β 1 is the 1st a current compensation resistance relative deviation, and β 2 waits.

Above α i, β i is 10 ^-2-10 ^-3Magnitude, and γ i is 10 ^-4Below the magnitude, when compensating resistance, can consider the influence of γ i.

From node 1,3,5,7,9, I11 entered the electric current of circuit when I1, I3, I5, I7, I9, I11 represented short circuit in parallel respectively, I2, and I4, I6, I8, I10 represent respectively from node 2,4, and 6,8,10 flow out the electric current of circuit.

I1 ', I2 ' ..., I11 ' represents the electric current of flowing through on each potential compensation resistance respectively.

The open-circuit voltage of seeing into from two current potential short-circuit ends when the V among V-1 and the V-2 represents short circuit in parallel.

I1, i2 ..., i10 represents the electric current of flowing through on the 1-10 operating resistance respectively.

Arrow is to separate the direction of current that Kirchhoff's equation presupposes.

With kirchhoff current/voltage law above compensating circuit being carried out error below calculates.

If in perfect condition,

-------------------------------------------formula 1

And according to the circuit of as above figure compensation method design, the external world passes to electric current I when short circuit in parallel, and current equation is:

I＝I1+I3+I5+I7+I9+I11＝I2+I4+I6+I8+I10＝i1+i2+i3+i4+i5+i6+i7+i8+i9+i10

Odd number potential compensation end

Even number potential compensation end

I1=I1 '+i1, I3=I3 '+i2+i3 ..., I9=I9 '+i8+i9, I11=I11 '+i10, totally 6 equations.

I2=I2 '+i1+i2 ..., I10=I10 '+i9+i10, totally 5 equations.

The kirchhoff voltage equation:

V＝i1·R-I1′·2A(1+α1)+I2′·A(1+α2)

i1·R-I1′·2A(1+α1)＝i2·R-I3′·A(1+α3)

i3·R-I3′·A(1+α3)＝i4·R-I5′·A(1+α5)

i5·R-I5′·A(1+α5)＝i6·R-I7′·A(1+α7)

i7·R-I7′·A(1+α7)＝i8·R-I9′·A(1+α9)

i9·R-I9′·A(1+α9)＝i10·-I1′·2A(1+α11)

I1·2B(1+β1)+i1·R＝I3·B(1+β3)+i2·R

I3·B(1+β3)+i3·R＝I5·B(1+β5)+i4·R

I5·B(1+β5)+i5·R＝I7·B(1+β7)+i6·R

I7·B(1+β7)+i7·R＝I9·B(1+β9)+i8·R

I9·B(1+β9)+i9·R＝I11·B(1+β11)+i10·R

i2·R+I2′·A(1+α2)＝i3·R+I4′·A(1+α4)

i4·R+I4′·A(1+α4)＝i5·R+I6′·A(1+α6)

i6·R+I6′·A(1+α6)＝i7·R+I8′·A(1+α8)

i8·R+I8′·A(1+α8)＝i9·R+I10′·A(1+α10)

i2·R+I2·B(1+β2)＝i3·R+I4·B(1+β4)

i4·R+I4·B(1+β4)＝i5·R+I6·B(1+β6)

i6·R+I6·B(1+β6)＝i7·R+I8·B(1+β8)

i8·R+I8·B(1+β8)＝i9·R+I10·B(1+β10)

I is known, more than total V, I1 ... I11, I1 ' ... I11 ', i1 ... i10, totally 33 unknown quantitys.

More than have 33 independent linearity equations, select potential compensation resistance to be far longer than current compensation resistance, promptly A＞＞B, ignore α i, β i sum of products high-order in a small amount, and notice R＞＞A, R＞＞B, the above equation of simultaneous can solve

$V\≈I\·\frac{R}{10}(1-\frac{4}{11}\·\frac{\mathrm{AB}}{R(A+B)}(\mathrm{\α}1\·\mathrm{\β}1+\mathrm{\α}2\·\mathrm{\β}2+\·\·\·+\mathrm{\α}11\·\mathrm{\β}11))$ ----formula 2

$\≈I\·\frac{R}{10}(1-\frac{4}{11}\·\frac{B}{R}(\mathrm{\α}1\·\mathrm{\β}1+\mathrm{\α}2\·\mathrm{\β}2+\·\·\·+\mathrm{\α}11\·\mathrm{\β}11))$

Compare with formula 1, formula 2 is the equivalent resistances in parallel after electric resistance array adds the resnstance transformer network, and at this moment relative error is exactly

------------------------------------------formula 3

If α _MaxBe max value of error in the potential compensation resistance, β _MaxBe max value of error in the potential compensation resistance, then the maximum relative error of the circuit of process Compensation Design is ---------------------------------------formula 4

4 explanation current compensation resistance nominal resistance B are the smaller the better for formula, simultaneously, and the maximum deviation β in these 11 current compensation resistance _MaxThe smaller the better, if get B=0.01 Ω, β _Max=10 ^-2, be that market economy cost and technical requirement integrate the higher selection of cost performance.Choose A=0.5 Ω simultaneously, α _Max=10 ^-3, satisfy A＞＞requirement of B, for 10 * 10 Ω arrays, R=10 Ω, Δ _Max=4 * 0.01 * 10 ^-2* 10 ^-3/ 10=4 * 10 ^-8For 10 * 100 Ω arrays, R=100 Ω, Δ _Max=4 * 0.01 * 10 ^-2* 10 ^-3/ 100=4 * 10 ^-9, all satisfy the requirement of checking pin-point accuracy DC current comparator.

In order to realize that pin-point accuracy DC current comparator is at 1k Ω: 100 Ω, 100 Ω: 10 Ω, 10 Ω: 10: 1 proportional error checking of ranges such as 1 Ω, we utilize the series-parallel general principle system of resistance to carry out the checking of current comparator ratio, be to adopt 10 series-parallel systems to realize that earlier 100: 1 the fixed proportion of 1k Ω-10 Ω is with reference to (seeing that formula 3.) for instance with nominal resistance array A (for example 10 * 100 Ω), simultaneously with one 100 Ω measuring resistance B as the middle transitional bridge, do proportion measurement with A series value (10 * 100 Ω=1k Ω) and B value (100 Ω) by current comparator, current comparator draws ratio registration R _String(be the A series value: the B value), do proportion measurement with B value (100 Ω) value in parallel with A (100 Ω/10=10 Ω) then, current comparator draws ratio registration R _And(being B value: A value in parallel), according to formula 3., R _s=n ²R _p, just, so A series value=100A value in parallel is A series value/A value=100 in parallel.Because R _StringR _And=(the A series value: the B value) (B value: A value in parallel)=A series value/A value in parallel, more than push in the process, B is a transition bridge, and result of calculation and B are irrelevant, and be only relevant with A value in parallel with the A series value.As mentioned above, this ratio product equals 100 on principle, and the ratio product measured value R100 of current comparator _{String (registration)}R100 _{And (registration)}And have certain error between the true value 100, this error is that two 10: 1 proportional errors (1k Ω: 100 Ω-EsA/B, 100 Ω: 10 Ω-Ep B/A) accumulation of current comparator causes.

According to same step, realize 10: 1 the fixed proportion reference of 100 Ω-10 Ω again, with 10 * 10 Ω array C, as the transition bridge, measure 100 Ω with certain 10 Ω measuring resistance D: 10 Ω, 10 Ω: two ratios of 1 Ω with current comparator, with as a same reason above-mentioned, R10 _{String (registration)}R10 _{And (registration)}And have certain error between the true value 10, this error is that two 10: 1 proportional errors (100 Ω: 10 Ω-Es C/D, 10 Ω: 1 Ω-Ep D/C) accumulation of current comparator causes.

According to same step, realize 10: 1 the fixed proportion reference of 10k Ω-100 Ω, again with 10 * 1k Ω array E, as the transition bridge, measure 10k Ω with current comparator: 1k Ω, 1k Ω: two ratios of 100 Ω with certain 1k Ω measuring resistance F, with as a same reason above-mentioned, R1k _{String (registration)}R1k _{And (registration)}And have certain error between the true value 1k Ω, this error is that two 10: 1 proportional errors (10k Ω: 1k Ω-Es E/F, 1k Ω: 100 Ω-Ep F/E) accumulation of current comparator causes.

The current comparator measuring error is being identical with range, so can prove the Ω at 1k: 100 Ω ranges, Ep F/E=EsA/B is at 100 Ω: 10 Ω ranges, Ep B/A=Es C/D.

During verificating current comparator ratio, if R100 _{String (registration)}R100 _{And (registration)}, R10 _{String (registration)}R10 _{And (registration)}, R1k Ω _{String (shows Number)}R1k Ω _{And (registration)}Three indexs (10 that the ratio product is all up to specification ^-7-10 ^-8), can think that this current comparator ratio measure is accurately, the result is for meeting fully in checking.

Meet index (error＜1 * 10 if there are two in three products ^-7), have only one to exceed index (R10 for example _{String (registration)}R10 _{And (registration)}=100.00005, error is 5 * 10 ^-7), can prove that then current comparator is normal at other ranges, at 10 Ω: 1 Ω range Ep D/C ≈ 5 * 10 ^-7R1k _{String (registration)}R1k _{And (registration)}It also is same reason.

Meet index (error＜1 * 10 if there are two in three products ^-7), have only R100 _{String (registration)}R100 _{And (registration)}Exceed index, this situation is very rare, if occur such situation really, illustrates that then current comparator goes wrong at whole ranges, needs major tune-up.

All the other situations illustrate that all bigger proportional error appears in current comparator, need debug and overhaul again.It more than is the method for 10: 1 range errors of verificating current comparator.In sum, this verification method of the present invention utilizes the connection in series-parallel of twice electric resistance array and the accuracy that relatively comes enough verificating current comparators between the measuring resistance.

For each 1: 1 range of verificating current comparator, we take the measuring resistance transposition relatively.Below with 100 Ω be example specifically.Get two measuring resistance R with the nominal value pin-point accuracy ₁And R ₂, insert the measuring junction of current comparator bridge, R respectively ₁Connect the Rs end, R ²Connect the Rx end, carry out both proportion measurements, obtain ratio R (indicating value) as a result, its theoretical value is Rx/Rs=R ₂/ R ₁R then ₁And R ₂Switch, R ₁Connect the Rx end, R ₂Connect Rs end, carry out both proportion measurements once more, obtain ratio as a result its theoretical value of R ' (indicating value) be Rx/Rs=R ₁/ R ₂According to the method described above, therefore the theoretical value of R-1/R ' is 0, the error of indication is R (indicating value)-1/R ' (indicating value), because twice measurement is all with carrying out under the range, so current comparator at the error accumulation of this range twice, so the proportional error of this range is [R (indicating value)-1/R ' (indicating value)]/2.

The invention still further relates to a kind of demo plant that is used for the pin-point accuracy DC current comparator of resistance measurement, be used for accuracy 10 ^-7-10 ^-8The checking of the DC current comparator of magnitude, its preferred structure synoptic diagram as shown in Figure 9, comprise three groups or three groups of above connection in series-parallel electric resistance arrays, also comprise the levelling circuit, compensating circuit and authentication unit, described connection in series-parallel electric resistance array resistance in series array and the parallel resistance array that two or more constitute respectively with the nominal resistance connection in series-parallel of serving as reasons, nominal resistance number on the same group is not identical, the nominal value difference, described parallel resistance array connects compensating circuit, described compensating circuit with electric resistance array when in parallel external short-circuit piece the short circuit compensation is set, described compensating circuit is included between each resistance and its external current potential short-circuit piece in parallel and potential compensation resistance is set and between each resistance and its external current parallel short-circuit piece current compensation resistance is set, and the magnitude of the relative error of described potential compensation resistance and current compensation resistance is 10 ^-2-10 ^-3Connect by regular hexahedron four end pin node connection methods between described potential compensation resistance and current compensation resistance and the electric resistance array, described four end pin node are four end points of regular hexahedron, described four end points all are symmetrical arranged two end points on each face of regular hexahedron, this four ends pin node is how much and is symmetrical arranged on regular hexahedron, this regular hexahedron processes by the finish-milling mode and determines size according to nominal resistance, and described regular hexahedron diameter is 5mm～10mm; The levelling circuit comprise and four end pin node in two nodes between the current source that is provided with and and two other node between the open-circuit voltage that is provided with, described levelling circuit is used to align the symmetric levelling of hexahedral four end pin node, and described levelling comprises exchanges views levelling by a small margin to the part less than normal of the resistance between two nodes.Compensating circuit links to each other with tested dc comparator, draws connection in series-parallel ratio registration respectively thereby do proportion measurement by tested dc comparator; Described authentication unit according to the product of the connection in series-parallel ratio registration of each group connection in series-parallel electric resistance array respectively with the comparison of the accuracy magnitude of regulation, realize the ratio checking of current comparator.

Wherein, the connection in series-parallel electric resistance array comprises three groups, the same normal resistance of each group is respectively 100 Ω, 10 Ω and 1k Ω, each number of organizing nominal resistance is 10, for 100 Ω normal resistances, described proportion measurement comprises that dc comparator is 1k Ω at range: 100 Ω, 100 Ω: 10 Ω and 10 Ω: 10: 1 the proportion measurement of 1 Ω; For 10 Ω normal resistances, described proportion measurement comprises that dc comparator is 10: 1 the proportion measurement of 100 Ω-10 Ω at range; For 1k Ω normal resistance, described proportion measurement comprises that dc comparator is 10: 1 the proportion measurement of 10k Ω-100 Ω at range; When the product of the connection in series-parallel ratio registration of three groups of connection in series-parallel electric resistance arrays all meets 10 ^-7-10 ^-8During magnitude, described authentication unit determines that this current comparator proportion measurement is correct; When three groups of products have only nominal resistance is 100 Ω when exceeding standard, and described authentication unit verifies out that error appears in the whole ranges of current comparator; When three groups of products have only nominal resistance is 10 Ω or 1k Ω when exceeding standard, and described authentication unit verifies out that current comparator other ranges beyond this proportion measurement measured that exceeds standard are normal; The described authentication unit of residue situation verifies out that all proportional error appears in current comparator.

The respectively external current potential in the two ends of parallel resistance array short-circuit piece in parallel and current parallel short-circuit piece, described compensating circuit is for all being provided with the potential compensation resistance (A) that connects current potential short-circuit piece in parallel on the lead-in wire circuit except that each resistance that connects in four end pin node, and the current compensation resistance (B that connects the current parallel short-circuit piece, B＜＜A), the maximum relative error after compensating circuit compensates is

Wherein, α _MaxBe max value of error in the potential compensation resistance, β _MaxBe max value of error in the current compensation resistance.

The present invention is used for the demo plant of the pin-point accuracy DC current comparator of resistance measurement, can adopt the connection in series-parallel of the electric resistance array described in above-mentioned verification method and measuring resistance to compare and measure successively and realize that (accuracy reaches 10 to pin-point accuracy ^-7-10 ^-8Magnitude) proportional error of DC current comparator checking.This device can be respectively 10 * 100 Ω with three electric resistance arrays (connection in series-parallel electric resistance array+compensating circuit) that have compensation, 10 * 10 Ω, three arrays of 10 * 1k Ω, be contained in respectively in three casings, three measuring resistances are respectively 10 Ω, 100 Ω, 1k Ω is contained in respectively in three metallic cylinder.Above six elements combination are used, formed the current comparator demo plant together.

Should be pointed out that the above embodiment can make those skilled in the art more fully understand the invention, but do not limit the present invention in any way creation.Therefore; although this instructions has been described in detail the invention with reference to drawings and Examples; but; those skilled in the art are to be understood that; still can make amendment or be equal to replacement the invention; in a word, all do not break away from the technical scheme and the improvement thereof of the spirit and scope of the invention, and it all should be encompassed in the middle of the protection domain of the invention patent.

Claims (10)

1. verification method that is used for the pin-point accuracy DC current comparator of resistance measurement, the accuracy of described DC current comparator is 10 ^-7-10 ^-8Magnitude, it is characterized in that, at first make it constitute resistance in series array and parallel resistance array respectively with the nominal resistance connection in series-parallel two or more, described parallel resistance array adopts four end pin node structures to connect each parallel resistance two end node, and for electric resistance array when in parallel external short-circuit piece the short circuit compensation is set, described short circuit compensation is included in potential compensation resistance that is provided with between each resistance and its external current potential short-circuit piece in parallel and the current compensation resistance that is provided with between each resistance and its external current parallel short-circuit piece, the magnitude of the relative error of described potential compensation resistance and current compensation resistance is 10 ^-2-10 ^-3, four end pin node by regular hexahedron between described potential compensation resistance and current compensation resistance and the electric resistance array connect, and described four end pin node are how much and are symmetrical arranged on regular hexahedron; Do proportion measurement by tested dc comparator then, dc comparator draws connection in series-parallel ratio registration respectively; Adopt the above nominal resistance connection in series-parallel of three groups or three groups after tested dc comparator is done proportion measurement, nominal resistance number on the same group is not identical, the nominal value difference, according to the product of the connection in series-parallel ratio registration of each group connection in series-parallel electric resistance array respectively with the comparison of the accuracy magnitude of regulation, realize the ratio checking of this DC current comparator.

2. verification method according to claim 1, it is characterized in that, adopt three groups of resistance string parallel connected arrays, the same normal resistance of each group is respectively 100 Ω, 10 Ω and 1k Ω, each number of organizing nominal resistance is 10, for 100 Ω normal resistances, described proportion measurement comprises that dc comparator is 1k Ω at range: 100 Ω, 100 Ω: 10 Ω and 10 Ω: 10: 1 the proportion measurement of 1 Ω; For 10 Ω normal resistances, described proportion measurement comprises that dc comparator is 10: 1 the proportion measurement of 100 Ω-10 Ω at range; For 1k Ω normal resistance, described proportion measurement comprises that dc comparator is 10: 1 the proportion measurement of 10k Ω-100 Ω at range; Be meant according to the product of the connection in series-parallel ratio registration of each group connection in series-parallel electric resistance array and the more specific of accuracy magnitude of regulation: when the product of the connection in series-parallel ratio registration of three groups of connection in series-parallel electric resistance arrays all meets 10 ^-7-10 ^-8During magnitude, determine that this current comparator proportion measurement is correct; When three groups of products have only nominal resistance is 100 Ω when exceeding standard, and verifies out that error appears in the whole ranges of current comparator; When three groups of products have only nominal resistance is 10 Ω or 1k Ω when exceeding standard, and verifies out that current comparator other ranges beyond this proportion measurement measured that exceeds standard are normal; The residue situation verifies out that all proportional error appears in current comparator.

3. verification method according to claim 1 and 2, it is characterized in that, comprise also aligning the symmetric levelling of hexahedral four end pin node that described levelling comprises that the resistance part less than normal between two nodes that align in the hexahedral four end pin node exchanges views levelling by a small margin.

4. verification method according to claim 1 and 2 is characterized in that, described regular hexahedron is determined size by finish-milling and line cutting processing and according to nominal resistance, and described regular hexahedron rib is long to be 5mm～10mm.

5. verification method according to claim 2, it is characterized in that, on the lead-in wire circuit except that each resistance that four end pin node connect, be provided with respectively potential compensation resistance (A) and current compensation resistance (B, B＜＜A), the maximum relative error that passes through the circuit of Compensation Design is Wherein, α _MaxBe max value of error in the potential compensation resistance, β _MaxBe max value of error in the current compensation resistance.

6. a demo plant that is used for the pin-point accuracy DC current comparator of resistance measurement is used for accuracy 10 ^-7-10 ^-8The checking of the DC current comparator of magnitude, it is characterized in that, comprise three groups or three groups of above connection in series-parallel electric resistance arrays, also comprise compensating circuit and authentication unit, described connection in series-parallel electric resistance array resistance in series array and the parallel resistance array that two or more constitute respectively with the nominal resistance connection in series-parallel of serving as reasons, nominal resistance number on the same group is not identical, the nominal value difference, described parallel resistance array connects compensating circuit, described compensating circuit with electric resistance array when in parallel external short-circuit piece the short circuit compensation is set, described compensating circuit be included in the current potential short-circuit piece in parallel that is provided with between each resistance and its external current potential short-circuit piece in parallel potential compensation resistance and and the current compensation resistance that between each resistance and its external current parallel short-circuit piece, is provided with, the magnitude of the relative error of described potential compensation resistance and current compensation resistance is 10 ^-2-10 ^-3, four end pin node by regular hexahedron between described potential compensation resistance and current compensation resistance and the electric resistance array connect, and described four end pin node are how much and are symmetrical arranged on regular hexahedron; Compensating circuit links to each other with tested dc comparator, draws connection in series-parallel ratio registration respectively thereby do proportion measurement by tested dc comparator; Described authentication unit according to the product of the connection in series-parallel ratio registration of each group connection in series-parallel electric resistance array respectively with the comparison of the accuracy magnitude of regulation, realize the ratio checking of this DC current comparator.

7. demo plant according to claim 6, it is characterized in that, also comprise the levelling circuit, described levelling circuit comprise and four end pin node in two nodes between the current source that is provided with and and two other node between the open-circuit voltage that is provided with, described levelling circuit is used to align the symmetric levelling of hexahedral four end pin node, and described levelling comprises exchanges views levelling by a small margin to the part less than normal of the resistance between two nodes.

8. according to claim 6 or 7 described demo plants, it is characterized in that, described connection in series-parallel electric resistance array comprises three groups, the same normal resistance of each group is respectively 100 Ω, 10 Ω and 1k Ω, each number of organizing nominal resistance is 10, for 100 Ω normal resistances, described proportion measurement comprises that dc comparator is 1k Ω at range: 100 Ω, 100 Ω: 10 Ω and 10 Ω: 10: 1 the proportion measurement of 1 Ω; For 10 Ω normal resistances, described proportion measurement comprises that dc comparator is 10: 1 the proportion measurement of 100 Ω-10 Ω at range; For 1k Ω normal resistance, described proportion measurement comprises that dc comparator is 10: 1 the proportion measurement of 10k Ω-100 Ω at range; When the product of the connection in series-parallel ratio registration of three groups of connection in series-parallel electric resistance arrays all meets 10 ^-7-10 ^-8During magnitude, described authentication unit determines that this current comparator proportion measurement is correct; When three groups of products have only nominal resistance is 100 Ω when exceeding standard, and described authentication unit verifies out that error appears in the whole ranges of current comparator; When three groups of products have only nominal resistance is 10 Ω or 1k Ω when exceeding standard, and described authentication unit verifies out that current comparator other ranges beyond this proportion measurement measured that exceeds standard are normal; The described authentication unit of residue situation verifies out that all proportional error appears in current comparator.

9. according to claim 6 or 7 described demo plants, it is characterized in that described regular hexahedron forms by finish-milling and line cutting processing and determines size according to nominal resistance, described regular hexahedron rib is long to be 5mm～10mm.

10. demo plant according to claim 8, it is characterized in that, on the lead-in wire circuit except that each resistance that four end pin node connect, potential compensation resistance (A) and current compensation resistance (B are set respectively in the described compensating circuit, B＜＜A), the maximum relative error after compensating circuit compensates is

Wherein, α _MaxBe max value of error in the potential compensation resistance, β _MaxBe max value of error in the current compensation resistance.

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