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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...
We have measured Newton's gravitational constant with a commercially available mass comparator. In this experiment, the difference of the gravitational force of 13,600 kg mercury on two 1.1 kg copper masses was measured with a relative statistical uncertainty of 16.3times10-6. Including the systematic uncertainties we determine the gravitational constant G to be 6.674 252(122)times10-11 m3kg-1s-2.
The discovery of the quantum Hall effect (QHE) in 1980 by Klaus von Klitzing has revolutionized the resistance metrology. Today, the quantized Hall resistance (QHR), observed in a two-dimensional electron gas exposed to a high magnetic flux at low temperatures, is used worldwide as an invariant reference for electrical calibrations. It has improved the reproducibility of calibration results by up...
To solve the problem of channel-closing of multichannel comparator for heavy direct current, a new method is proposed that an air gap is set between every two channels in the DC comparator. This method fairly prevents the channels of multi-channel comparator from closing, and guarantees high precision measurement. By calculation, the comparator of four channels, with the total length of air gaps to...
The paper describes a standard system for traceable measurements of electrical power of sinusoidal signals at voltages up to 1000 V, currents up to 20 A and frequencies from 40 Hz to 200 kHz. The system uses thermoelectric effects to relate the alternating power to that of known dc signals. It is comprised of a thermal power comparator, inductive and resistive voltage dividers and a range of wideband...
The deviation of serial and parallel ratios of direct current (DCC) comparator is investigated. By matching the currents passing the paralleled windings with the same nominal value, the deviation of the ratio of a group paralleled windings to the same group serial windings could be reduced to a negligible level. A suit of DCC with serial and parallel structure was developed to build the traceability...
A calculable potential transformer (PT) with a nominal ratio error of -10 % to +10 % has been developed on basis of theoretical calculation of ratio error by the number of primary windings. The developed wide ratio error PT (WRE PT) can be used to evaluate the linearity and accuracy of the PT comparator by comparing both the theoretical and experimental values of the WRE PT. The WRE PT has been applied...
An AC magnetic flux density standard system was constructed for calibration in KRISS magnetometers and for the testing of the magnetic field characteristics of sensors and materials in the frequency range below 20 kHz. This system consists of an AC magnetic field converter, a Helmholtz coil, a voltage comparator, a voltmeter, a standard resistor, and a computer with a program for automatic measurement...
Application of ratio voltage or current transformers allows to use commercial digital LCR-meter as a comparator of two impedances. Advantages of such comparison method include the opportunity to increase the resolution up to 7-8 digits and the elimination of an error from nonlinearity of a meter.
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