AC impedance, HF power

In electrical metrology SP realises today units of resistance, capacitance and inductance of up to about 10 kHz, while we in microwave metrology have well-defined standards from 100 MHz upwards.

The aim of this project is to link the realisation of impedance and thus improve traceability in the frequency range 10 kHz - 100 MHz.

Realisation of current ac-dc difference

We have developed an own realisation of a current ac-dc difference at the primary level of 10 mA in the frequency range 10 Hz to 100 kHz. The realisation is based on the measurement of the loss components (reactive and resistive) with a "Single Junction Thermal Converter" (SJTC), together with modelling and measurements to verify the model. This work has potential for publication and is also the basis for the reporting of our results in a key comparison, CCEM-K12 in which we have been participated and are the coordinator for.

Realisation for current to 1 MHz

Work on the realisation of this ac-dc difference has resulted in an own realisation for current to 1 MHz at 5 mA and 10 mA. This work formed the basis for our participation in key comparison CCEM-K12 concerning power ac-dc difference at 100 kHz.

In 2008, the realisation was repeated and improved by using a pair of new standards and a better modelling of these. This has especially given improvements at higher frequencies in the range 100 kHz - 1 MHz and provides the tools to be able to extend the frequency range further. An uncertainty analysis has been made where the expanded uncertainty of the realised power ac-dc difference has been reduced to 6 μA / A at 10 mA, 1 MHz. The results were presented at CPEM 2008, Broomfield, CO, USA.

Related Information


Metrological research

Business Areas

RISE Safety and Transport

Contact Persons

Karl-Erik Rydler

Phone: +46 10 516 54 01

RISE Research Institutes of Sweden, Phone 010-516 50 00, E-mail

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