CCEM-K10 and EUROMET.EM-K10

MEASURAND : Resistance
NOMINAL VALUE : 100 ohms

Degrees of equivalence D_i and expanded uncertainty U_i (k = 2)

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Red diamonds: participants in CCEM-K10
Green triangles: participants in EUROMET.EM-K10 only

Zoomed graph for CCEM-K10 participants only

CCEM-K10 and EUROMET.EM-K10

MEASURAND : Resistance
NOMINAL VALUE : 100 ohms

Degrees of equivalence D_i and expanded uncertainty U_i (k = 2)

In blue: linking laboratories
In green: participants in EUROMET.EM-K10 only

* Denotes laboratories that claim an uncertainty smaller than the transport uncertainty. For these laboratories the result reflects the limited knowledge on the behavior of the travelling standards and not the capability of the laboratory.
** Denotes that the result was obtained by a repeated measurement in October 2006.

Results are presented under A4 printable format in Summary Results (.PDF file).

CCEM-K10 and EUROMET.EM-K10

MEASURAND : Resistance
NOMINAL VALUE : 100 ohms

PILOT LABORATORY : PTB

• Key comparison CCEM-K10

• Linking EUROMET.EM-K10 to CCEM-K10

The linking laboratories are MIKES, METAS, BIPM and PTB.
The linkage process is explained in Section 6.4 of the EUROMET Final Report.

CCEM-K10 and EUROMET.EM-K10

• Key comparison CCEM-K10

MEASURAND : Resistance
NOMINAL VALUE : 100 ohms

PILOT LABORATORY : PTB

x_i : result of measurement carried out by laboratory i, expressed as the relative deviation from the nominal value R₀ = 100 ohms, namely R_i = R₀·(1 + x_i) where R_i is the resistance measured by laboratory i. The x_i’s are corrected to a nominal temperature of 23 °C and a nominal pressure of 1013.25 hPa.
U_Labi : expanded uncertainty (k = 2) of x_i

Four different transfer standards have been used.

Individual measurements are combined as follows:
D_i-comb : combined mean of the travelling standards relative differences from a least-squares regression of the PTB values for each travelling standard
U_i-comb : expanded uncertainty (k = 2) of D_i-comb
U_i-comb,T : expanded uncertainty (k = 2) of D_i-comb, including an additional travel uncertainty estimated to 7 x 10^-9

The calculation of the D_i-comb’s and the U_i-comb’s is described in detail in Section 6 on page 7 of the CCEM-K10 Final Report.

• Key comparison EUROMET.EM-K10

MEASURAND : Resistance
NOMINAL VALUE : 100 ohms

PILOT LABORATORY : PTB

Measurements were carried out using three sets of transfer standards in three loops in parallel. Corresponding results are reported in Tables 1 to 9 of Appendix A of the Final Report.
Measurement dates are given in Section 2 of the Final Report.

The PTB is the only common laboratory to all loops and is used to link them (see Section 6 of the Final Report). Results are then expressed in terms of D_{i-comb EUR}, the combined measurement of laboratory i relative to the PTB, and U_{i-comb EUR}, the expanded uncertainty (k = 2) of D_{i-comb EUR} taking into account the travel uncertainty. These values are available in Table 16 of the Final Report.

The EUROMET reference value, x_{R EUR}, and its associated expanded uncertainty
(k = 2), U_{R EUR}, are determined from the weighted mean of the D_{i-comb EUR} with the U_{i-comb EUR} used as weights. In this calculation only one value is considered for the pilot laboratory, and to exclude possible correlation, only those laboratories having their own representation of the ohm, based on the QHE, are taken into consideration.
x_{R EUR} = 4.0 10^-9 and U_{R EUR} = 6.0 10^-9

Degrees of equivalence inside the EUROMET key comparison are deduced using the appropriate equations (see Section 6.3 of the Final Report). They are given by a pair of terms: D_{i EUR}, the laboratory i offset relative to the EUROMET reference value, and the associated expanded uncertainty (k = 2), U_{i EUR}.

Italics: acronyms of laboratories whose results are not used for the calculation of the EUROMET reference value.
* Denotes laboratories that claim an uncertainty smaller than the transport uncertainty. For these laboratories the result reflects the limited knowledge on the behavior of the travelling standards and not the capability of the laboratory.
** Denotes that the result was obtained by a repeated measurement in October 2006.