Interlaboratory Comparison in Measuring Low Levels of AC Voltage between Italy and Egypt

Abstract

The paper describes an interlaboratory comparison program between the National Institute for Standards (NIS), Egypt and the Istituto Nazionale di Ricerca Metrological (I.N.Ri.M.), Italy for measuring low ac voltages. The aim of this program is to demonstrate the technical competence of both institutes. The interlaboratory comparison has been carried out under the framework of the executive program of scientific and technological cooperation between Italy and Egypt. A Fluke model 792A has been used as a travelling standard, which was calibrated against the reference standard of NIS and I.N.Ri.M. at 10, 20, 50, 100 and 200 mV at 40 Hz, 1 kHz, 10 kHz and 20 kHz. The standards of the two institutes, NIS and I.N.Ri.M., have been used to calibrate the traveling standard at 10, 20, 50, 100 and 200 mV at frequencies of 40 Hz, 1 kHz, 10 kHz and 20 kHz. The ac–dc transfer difference results of the traveling standard are evaluated then compared at the intended frequencies. In this paper, the comparison results are discussed in detail. The performance of this test is also judged by calculating the relative error normalized with respect to the uncertainty of the measurement. The comparison results and the efficiency test En values show a good agreement between the NIS and the I.N.Ri.M. systems in assigning ac–dc transfer difference.