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This paper describes 3 important improvements in high resistance measurements: the fabrication of a container to provide a moisture free environment to the resistive element; the development of high value standard resistors that can be connected to a split guard potential to reduce leakage currents, and the automation of an Active-Arm Bridge which improved the measurement results and reduced the calibration time.

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This paper describes the development of bifilar, quadrifilar, and octofilar Calculable Resistors (CRs). The research involves Evanohm-S and Isaohm wire heat treatment processes to achieve temperature coefficients less than 0.5 µΩ/Ω/ • C in the CR's wire resistance element, tests of different terminal-wire joining techniques, and construction aspects achieving a stability of less than 0.05 µΩ/Ω/day. This kind of construction methodology has not been presented in detail in previous CR papers, and it is essential to accomplish the correct parameters of a CR. Without it, the development of a CR can take several months or even years. A comparison between CRs developed in this research and a CR from the Federal Institute of Metrology (METAS) in Switzerland was carried out. Measurement results between the 10 kΩ octofilar CR and the METAS 1 kΩ coaxial CR show an agreement better than 0.35 µΩ/Ω through the audio-frequency range. Therefore, the octofilar CR can be used as an AC resistance reference with traceability to the quantum Hall resistance in DC.

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