HATS-LR Low Resistance Transfer Standard

• Values from 1 Ω - 100 kΩ
• Initial Accuracy... As good as 10 ppm of nominal value
• Transfer Accuracy... ± (1 ppm + 0.1uΩ at parallel value) for 10:1 & 100:1 ratios
• Long Term Accuracy... ± 10 ppm/year
• Calibration Accuracy... ± 5 ppm

The HATS-LR resistance transfer standards consist of 12 equal resistance steps. These steps are available in increments of 1 Ω, 10 Ω, 100 Ω, 1 kΩ, 10 kΩ, and 100 kΩ. The HATS-LR provides four-terminal connections for each step or for series and parallel combinations of these resistance steps using the optional Series-Parallel (SPC102), Parallel Compensation Networks (PC101) and shorting bars (SB103).

Description
The HATS-LR meets or exceeds all of the requirements for resistance transfer standards in precision measurement applications. It is easily configured to transfer resistances up or down a decade from their initial resistance value. When used with the connecting networks and shorting bars, it provides 1 ppm transfer accuracies.

Each transfer standard contains twelve equal value precision resistors connected in series by specially designed true 4-terminal junctions. These special junctions assure that a 4-terminal measurement of a series of resistors agrees with the sums of the individual resistors in the series. Accurate parallel connections can be made with the Parallel Compensation Network and the Shorting Bars connected to the junctions.

These standards can be connected to provide three decade values: 10 resistors in series, 10R: 9 resistors in series - parallel, 1R: and 10 resistors in parallel, R/10. The part per million accuracy is assured as the series value is equal to 100 times the parallel value to better than 1 ppm. The series - parallel value relative to either the series value or the parallel value can be found to better than 1 ppm by making a 1:1 comparison with the remaining tenth resistor and a simple calculation.

The accuracy and precision of the individual resistors also make the HATS-LT transfer standards ideal for use as a multi-value standard resistor or reference voltage divider.

Advantages of Transfer Standards
In order to perform calibrations with a high degree of accuracy, reference standards must be employed at every range or decade of the measuring or calibration instrumentation. Clearly, this can be difficult and costly since these standards must be highly stable and their precise values must be known with a high degree of certainty and sufficient resolution.

To minimize the cost and difficulty, more practical means of performing such calibrations is to use transfer standards.

If one has a single standard that is calibrated by a national laboratory, one can then compare the transfer standards to the certified standard by ratio techniques. See our Technical Applications section for a full tutorial

Specifications

Resistor Type: Wirewound, hermetically sealed, low inductance.

Step Size: 1 Ω, 10 Ω, 100 Ω, 1 kΩ, 10 kΩ, or 100 kΩ.

Initial Accuracy: <±15 ppm for 1 Ω, 10 Ω steps; <±10 ppm for 100 Ω through 100 kΩ steps.

Long Term Accuracy: <±10 ppm/year;

Transfer Accuracy: ±(1 ppm + 0.1 μΩ) for 10:1 and 100:1 ratios for 1 Ω, 100 Ω, 1 kΩ, 10 kΩ, and 100 kΩ steps;
±1 ppm for 10:1 and 100:1 ratios for 10 Ω step.
(Transfer accuracies apply when SB103, fixtures are used)

Matching Accuracy: within 10 ppm for 1 Ω, 10 Ω steps; within 5 ppm for 100 Ω through 100 kΩ steps.

Matching Temperature Coefficient: within 5 ppm/°C for 1 Ω step; within 1 ppm/°C for ≥ 100 Ω steps and for HATS-LRTC-10 within 2 ppm/°C for HATS-LR-10 only

Matching Calibration Accuracy: <10 ppm for 1 Ω, <5 ppm for all others

Temperature Coefficient: ±1 ppm/°C for HATS-LRTC-10 (low TC version), ±10 ppm/°C for HATS-LR-1;, ±3 ppm/°C for HATS-LR-10;, ±2 ppm/°C for HATS-LR-100 through 100K.