engleski

Maintenance of Croatian resistance standards

An accredited (National) laboratory for electrical measurements in Croatia was established at the Faculty of Electrical Engineering and Computing (FER, previously ETF - Faculty of Electrical Engineering) University of Zagreb in 1994. Operating within Department of Electrical Engineering Fundamentals and Measurements of the Faculty, its main task was to ensure a system of international traceability for the basic electromagnetic standards, usable for calibration of maintining, secondary and working standards in other calibration and testing laboratories arround the country. Together with the Voltage Balance ETF-84 as the primary voltage standard and Cs-clock as the frequency and time standard, it was necessary to build up a group of accurate resistors as a primary Ohm standard. The methods of maintaining and calibrating these resistors placed in a specially constructed ultrathermostat, as well as the results of their first intercomparisons, are the subject of discussion in this paper. From the first measurement results with two digital voltmeters we expect that in further comparisons of resistors within the group between 1 ohm and 100 kiloohm the uncertainty would not exceed the level of 0, 05 ppm, at the prescribed level of confidence k=2 (from the newest ISO guides on expression of uncertainties).

Croatian resistance standards

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