Karl-Erik Rydler

A measuring system for the calibration of power analyzers

A digital sampling watt meter has been designed for calibration of power analyzers. The watt meter is based on two commercially available sampling DVMs. The power spectrum is calculated with DFT analysis. High accuracy is achieved by phase locking and simultaneous sampling. >

Voltage dividers with low phase angle errors for a wideband power measuring system

A set of resistive voltage dividers has been designed for low phase angle errors. The dividers were made for a wideband power measuring systems to cover voltages up to 1000 V. The phase angle errors of the dividers have been verified in a step-up procedure using two sampling voltmeters. Except for the highest ranges the phase angle errors are within a few /spl mu/rad at 50 Hz and within /spl plusmn/ 50 /spl mu/rad at 1500 Hz.

High precision automated measuring system for AC-DC current transfer standards

An automated measuring system for AC-DC current transfer standards were developed at the Swedish National Testing and Research Institute (SP). The use of a guard makes intercomparisons with ppm precision possible at frequencies up to 100 kHz. Two multijunction thermal converters are used for evaluating the uncertainty of the system. >

An international comparison of 50/60 Hz power (1996-1999)

An international comparison of 50/60 Hz power is described. The traveling standard was an electronic power transducer which was tested at 120 V, 5 A, 53 Hz, at five power factors (1.0, 0.5 lead, 0.5 lag, 0.0 lead, and 0.0 lag). Fifteen national metrology institutes from six metrology regions participated in the comparison.

Extending ac-dc current transfer measurement to 100 A, 100 kHz

This paper describes the design and verification of current shunts for AC-DC transfer measurements in the range 20 A to 100 A. The measured AC-DC current transfer difference of the 100 A shunt is -36 muA/A at 100 kHz with an uncertainty of 200 muA/A.

Improved Model and Phase-Angle Verification of Current Shunts for AC And Power Measurements

The phase angle error of the output voltage of resistive shunts may depend on a number of stray impedance components. These components have been estimated for some shunt designs. Their total contribution has been measured by a LCR meter method and compared to a step-up procedure. The agreement between the different methods, for measureme nt of phase angle difference of two shunts, was within a few murad at 1500 Hz

Determination of Transition Error Corrections for Low Frequency Stepwise-Approximated Josephson Sine Waves

This paper describes high-accuracy low-frequency ac voltage measurements using a programmable Josephson voltage standard based on a binary Josephson array. AC voltage synthesis is performed by switching between quantized Josephson voltages. The accuracy of a synthesized Josephson ac voltage is limited by the transition error. We present an experimental method for determination of a correction for the transition error. The method is based on the assumption of a linear frequency dependence of the transition error. Measurements up to 1 kHz have been performed. Using the transition error correction at different frequencies has shown a frequency-independent Josephson ac voltage step width.

Level dependence of AC-DC transfer devices

A new method based on summing of phase controlled AC voltages makes it possible to compare thermal voltage converters with a ratio of 2:1 without introducing any error due to level dependence. The method is used to determine the level dependence of thermal voltage converters up to 1 kV and 100 kHz. The level dependence is compared to the change of AC-DC transfer difference due to power dissipation in the range resistor and due to DC-effects in the thermal converter. The results for two investigated TVCs indicate that the power dissipation is the only cause of level dependence in the range resistor of a high voltage TVC.

A Precision Current Source Using

We present a new source for currents in the picoampere range based on the charging of a capacitor at a constant rate. The voltage ramp is generated using Delta-Sigma modulation and low-pass filtering. This method ensures the linearity of the voltage ramp by calibrating a small number of voltage levels prior to generating the current. Our analysis shows that we can calibrate a picoampere meter with a standard uncertainty of less than 20 μA/A at 10 pA.

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An automatic zero-power-factor standard has been designed and compared with a digital sampling wattmeter standard. The agreement of the two power measuring standards at 120 V, 5 A, and zero power factor is within a few /spl mu/W/VA. The paper describes the standards, the phase errors and uncertainties of the two standards.