The Josephson effect based primary ac power standard at PTB: progress report

In its effort to continuously improve its capability for measuring active, reactive and apparent electrical power, the Physikalisch-Technische Bundesanstalt (PTB) has integrated a 10 V Josephson Waveform Synthesizer into its primary standard for electrical ac power. This direct link to a quantum standard provides direct traceability for the measurements by the digital sampler at the heart of the standard, besides reducing the uncertainty for measuring active, reactive and apparent power at the 600 VA apparent power level beyond the present level of 1.2 muW/VA (k = 1).