Characterisation of Thermal Converters with a Programmable Josephson Standard

Purpose and goal

To realise the SI units for alternating voltage (V), alternating current (A) and electric power (W) at RISE, thermal converters are used to compare a known dc voltage with an unknown ac voltage. Each thermal converter has an error (ac-dc difference) that needs to be characterized as part of the realisation. Today, we do not have a complete method for measuring the ac-dc difference and must rely on old values. The goal of this project is to develop a new method using our Josephson standard.

Expected effects and result

After the project, RISE will be one of few NMIs (National Metrology Institutes) in the world with its own realisation of the electrical (alternating) units, which makes us independent of external actors and increases the security of the traceability chain. The new methods will be used to improve measurement uncertainty for calibration in the low-frequency range (<1 khz), especially at 3–10 hz, as measuring instruments with significantly better performance have been made available on the market.>

Planned approach and implementation

To achieve the project goals, new methods need to be developed to characterize the thermal converters at RISE, which are reference standards and maintain the traceability of the alternating electrical units. The characterisation will be done with our programmable Josephson standard, which can generate exactly defined (quantised) dc voltages and ac voltage signals with calculable root mean square (RMS) value.