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There are a lot of advantages in a power bridge using a current comparator, such as for can be the structure concise, the limitation of the number of error factors etc. However, a small problem might be left about a point how carry out the calibration of the comparator. This problem is settled immediately if the comparator could be replaced with a current transformer. Therefore it is assumed that...
To validate an inductance resonance bridge, which is based on a commercial capacitance bridge, a second resonance bridge was built, based on a self-composed 4 terminal-pair impedance ratio bridge. From analysis of the results on 100 mH standards at 1 kHz, discrepancies have been resolved and the uncertainty has been improved to 26 muH/H.
Two simulant high-power resistance standards were newly developed at NIM. The first resistance standard uses a high-power resistor for signal sampling, IVD for adjustment, and a voltage-follower for output. The high-power low-resistance resistor has similar input/output characteristic as the simulated variable and can carry more load power. The second resistance standard uses resistance network for...
A two-way Josephson voltage standard (JVS) direct comparison between the National Institute of Standards and Technology (NIST) and the National Research Council (NRC) has been conducted. The process consists of two comparisons, one using NIST designed hardware and software and the other using NRC designed hardware and software. The results of the two comparisons are in agreement to within 0.7 nV and...
This paper describes the method used to establish the traceability of LNE AC-DC transfer standards in the mV-range to the 1 V multijunction converter, which serves as the primary AC-DC standard. Main uncertainty components are listed and final uncertainty given for the different voltage levels. An independent method was developed for the calibration of thermal converters at 0.3 V and 0.2 V. The agreement...
The progress in developing Josephson voltage system contributes an increasing in the accuracy of the voltage unit transfer. Using the different methods during voltage standard key comparisons allows defining accuracy of compared standard with uncertainty, differing in 10-100 once. Some issues concerning measurement procedure to follow in voltage key comparison are discussed.
This paper presents the French project aiming to determine the von Klitzing constant RK with an uncertainty of one part in 108. The design adopted for a new Thompson-Lampard calculable capacitor and some parts of the impedance comparison measurement chain are presented.
A new coaxial cylindrical cell with guard electrodes has constructed and a unique approach to determine the cell constant by means of capacitance of the cell in air has been presented. The new cell is very stable in both construction and performance. With this technique, an uncertainty of 0.1% in measuring conductivity of aviation fuel and other liquids can be achieved.
A semi automated Cryogenic Current Comparator (CCC) system for precision resistance measurements, RX(Omega), has been developed within a joint collaboration ICMA-TPYCEA. The system, installed at TPYCEA, has an uncertainty of plusmn8ldr10-9ldrRX (k=1) and is being used in conjunction with the previously developed Quantum Hall Resistance system.
Two-way satellite time and frequency transfer has become an important technical component in the process of the realization of International Atomic Time and also for comparisons among the best primary frequency standards. This paper contains results of studies aimed at improving the knowledge of the uncertainty for true time transfer between remote sites. Our study addresses mostly the collection...
A high-accuracy system for calibration of Rogowski coils using current transformers and digital sampling is described in the paper. An automated version of the calibration system is capable of operating at currents up to 2,000 A, at power frequencies. A semi-automated version is capable of operating at currents up to 60,000 A. The uncertainty of the calibration system is estimated to be better than...
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