• Otto Wolff 14142/5 100 µΩ oil bath resistance standard, rated current 200 A
• Guildline Type 9290 shunt, 10 mΩ, rated current 100 A, air cooled. S/N 26140
• Leeds & Northrup 4221 100 mΩ and 4223-B 1 mΩ oil resistors
• L&N 4221 resistance standard S/N 1554760
• L&N 4221 resistance standard S/N ?
• L&N 4222 resistance standard S/N 1591015

Otto Wolff 14142/5 100 µΩ oil bath resistance standard, rated current 200 A

Measurement

Source setup: Fluke 5720A + Fluke 5725A, Isrc = 10A with polarity reversal

Detector setup: Keithley 2182A on 10mVDC range, channel 1, NPLC5

Wiring:

Result

Air temperature	Calculated resistance	Deviation from nominal, ppm
22.431	9.99897252E-05	-102.75 ppm
22.425	9.99900842E-05	-99.16 ppm
22.412	9.99902167E-05	-97.83 ppm
22.409	9.99902632E-05	-97.37 ppm
22.386	9.99906032E-05	-93.97 ppm
22.386	9.99901224E-05	-98.78 ppm
22.368	9.99903175E-05	-96.83 ppm
22.389	9.99906209E-05	-93.79 ppm
22.389	9.99900781E-05	-99.22 ppm
22.375	9.99902975E-05	-97.02 ppm
22.365	9.99900943E-05	-99.06 ppm
22.37	9.99900255E-05	-99.75 ppm
22.353	9.99905653E-05	-94.35 ppm
22.339	9.99899150E-05	-100.85 ppm
22.347	9.99900953E-05	-99.05 ppm
22.34	9.99902026E-05	-97.97 ppm
22.324	9.99905397E-05	-94.60 ppm
22.317	9.99903802E-05	-96.20 ppm
22.329	9.99902832E-05	-97.17 ppm
22.33	9.99903598E-05	-96.40 ppm
22.354	9.99902256E-05	-97.74 ppm
22.385	9.99905915E-05	-94.08 ppm
22.4	9.99905119E-05	-94.88 ppm
22.388	9.99903301E-05	-96.70 ppm
22.369	9.99903867E-05	-96.13 ppm
22.381	9.99904795E-05	-95.21 ppm
22.346	9.99905836E-05	-94.16 ppm
22.324	9.99906073E-05	-93.93 ppm
22.304	9.99903018E-05	-96.98 ppm
22.294	9.99905857E-05	-94.14 ppm
22.3	9.99906402E-05	-93.60 ppm
22.335	9.99902974E-05	-97.03 ppm
22.343	9.99900583E-05	-99.42 ppm
22.359	9.99903324E-05	-96.68 ppm

Calculated measurement

Median value : 99.99031 µΩ
Median deviation: -96.9 ppm @ +22.36 °C
Standard deviation: 0.2247 nΩ
Uncertainty: ±0.02 %
Date : 27 June, 2020

Guildline Type 9290 shunt, 10 mΩ, rated current 100 A, air cooled. S/N 26140

Same measurement setup.

Air temperature	Calculated resistance	Deviation from nominal, ppm
24.619	0.010001527	152.7265
24.618	0.010001571	157.0715
24.625	0.01000158	158.012
24.644	0.010001596	159.5695
24.635	0.010001597	159.7245
24.639	0.0100016	160.0495
24.648	0.010001606	160.5925
24.647	0.010001595	159.475
24.666	0.010001612	161.164
24.673	0.010001616	161.613
24.663	0.010001595	159.515
24.665	0.010001598	159.819
24.685	0.01000161	160.9785
24.681	0.010001613	161.324
24.69	0.010001615	161.4505
24.725	0.010001634	163.413
24.797	0.010001624	162.4125
24.798	0.010001629	162.934
24.789	0.010001624	162.4365
24.775	0.010001635	163.4675
24.778	0.010001637	163.73
24.797	0.010001635	163.5465
24.767	0.010001639	163.866
24.778	0.010001646	164.5675
24.759	0.010001644	164.412
24.774	0.010001643	164.341
24.774	0.010001632	163.225
24.794	0.010001635	163.493
24.765	0.010001653	165.277
24.75	0.010001646	164.592
24.737	0.010001654	165.394
24.761	0.010001646	164.5955
24.775	0.010001651	165.089
24.79	0.010001653	165.254
24.775	0.010001664	166.4035
24.771	0.010001655	165.5265
24.783	0.010001659	165.897
24.832	0.010001658	165.811
24.822	0.010001646	164.5745
24.826	0.010001651	165.0605
24.837	0.010001662	166.174
24.834	0.010001654	165.3935
24.82	0.010001658	165.811
24.815	0.010001664	166.441
24.812	0.010001666	166.575
24.865	0.01000166	165.951
24.927	0.010001678	167.8385

Calculated measurement

Median value : 10.001637 mΩ
Median deviation: +163.7 ppm @ +24.77 °C
Standard deviation: 29.44 nΩ
Uncertainty: ±0.02 %
Date : 27 June, 2020

Leeds & Northrup 4221 100 mΩ and 4223-B 1 mΩ oil resistors

Same measurement setup.

L&N 4221 resistance standard S/N 649642

Method: Fluke 5720A + Keithley 2182A nanovoltmeter
Median value : 100.05732 mΩ
Median deviation: +573.2 ppm @ +23.28 °C
Standard deviation: 43.9 nΩ
Uncertainty: ±0.02 %
Date : 26 June, 2020

L&N 4221 resistance standard S/N 1554760

Yet another L&N 4221 test.

Method: Measurements International 6010B DCC with Fluke SL935 1.00006279 Ω reference standard
Test current: 0.1 A, reversal 10s
Standard temperature: fixed +23.0 °C and TC sweep +16.5 … +29.5 °C
Calibrated assigned value : 99.98835 mΩ
Median deviation: +116.48 ppm @ +23.02 °C
Standard deviation: 26.4 nΩ
Uncertainty: 0.45 ppm
Date : 31 May 2022

L&N 4221 resistance standard S/N ?

3rd L&N 4221 test.

Method: Measurements International 6010B DCC with Fluke SL935 1.00006279 Ω reference standard
Test current: 0.1 A, reversal 10s
Standard temperature: fixed +23.0 °C and TC sweep +16.5 … +29.5 °C
Calibrated assigned value : ? mΩ
Median deviation: +? ppm @ +23.02 °C
Standard deviation: ? nΩ
Uncertainty: 0.45 ppm
Date : 1 June 2022

L&N 4222 resistance standard S/N 1591015

Method: Measurements International 6010B DCC with L&N 4221 0.09998835 Ω reference standard
Test current: 0.245 A, reversal 10s
Standard temperature: fixed +23.0 °C and TC sweep +16.5 … +29.5 °C
Calibrated assigned value : ? mΩ
Median deviation: +? ppm @ +23.02 °C
Standard deviation: ? nΩ
Uncertainty: 1 ppm
Date : 2 June 2022

L&N 4223-B resistance standard

Air temperature	Calculated resistance	Deviation from nominal, ppm
24.454	0.000999952	-47.962
24.443	0.000999954	-46.260
24.457	0.000999954	-45.944
24.457	0.000999952	-47.960
24.506	0.000999952	-47.505
24.515	0.000999952	-47.724
24.529	0.000999952	-48.200
24.541	0.000999952	-48.221
24.548	0.000999952	-48.165
24.582	0.000999953	-47.374
24.583	0.000999952	-48.206
24.565	0.000999953	-47.421

Median value : 0.9999522 mΩ
Median deviation: -47.8 ppm @ +24.52 °C
Standard deviation: 0.727 nΩ
Uncertainty: ±0.02 %
Date : 26 June, 2020

In future we will repeat measurements of all these resistors for temperature stability, using Fluke 7015 precision oil bath.