CALIBRATION OF 100 MΩ HAMON RESISTOR USING CURRENT-SENSING WHEATSTONE BRIDGE

• Abstract:

  Primary electromagnetic laboratory in Zagreb maintains standards of four major electromagnetic units: volt, farad, ohm and second. Reference standards are periodically calibrated in PTB (Germany) and several methods has been realized for internal laboratory traceability check. RC-comparison method uses Hamon divider constructed of 100 equally balanced 1-megaohm resistors that connected in parallel or serially exhibit Hamon ratio of 100 MΩ : 10 kΩ with relative uncertainty of 10^-8. Hamon resistance of 100 MΩ is directly compared with impedance of 100 pF capacitance reference at frequency of 15,873 Hz. Measurement of low-frequency voltage ratio is based on two digital voltmeters HP 3458A with improved algorithm for data processing. Accuracy of reference standards comparison 10 kΩ →100 pF depends on consistency of Hamon divider that can be disturbed by aging of used metal-film components. In this paper a recently realized method for accurate measurement of 100 MΩ Hamon resistor by means of comparison with calibrated and stable 10 MΩ resistance standard at higher voltage levels has been presented.
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• Download:

  IMEKO-TC4-2004-020.pdf
• DOI:

  _unreg_tc4-2004.020

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