AC voltage up to 100 MHz: GUM in the European Met4AC project — today no national metrology institute in Europe can fully calibrate such equipment
On 25 June 2026 Poland’s Central Office of Measures (GUM) announced that project 25RPT01 Met4AC “Advancing the European metrology for wideband AC voltage”, funded by the European Partnership on Metrology, started on 1 June. The kick-off meeting took place on 9–10 June at Germany’s PTB in Braunschweig with two GUM laboratories taking part.
- GUM describes the problem as follows: the performance of instruments measuring AC voltage at frequencies up to 100 MHz has improved considerably, but metrology has not kept pace, and there is currently no national metrology institute in Europe capable of fully calibrating such equipment. Without wideband AC voltage standards and sources, traceability cannot be disseminated from the primary level to calibration laboratories and industry.
- The project is to develop and validate novel RF-DC standards, improved measurement methods and set-ups for AC voltage from 1 mV to 50 V up to 100 MHz, and software for control and data processing. Ireland’s NSAI also lists the investigation of impedance load techniques and states that the consortium has 13 European partners.
- The kick-off was attended by staff of two GUM laboratories: Low Frequency Electrical Quantities Standards (Z42) and Microwaves, Electromagnetic Field and Electromagnetic Compatibility (Z44). GUM will develop a new measurement set-up — as it notes, a reduced one, not covering the full range of voltages offered — together with the Silesian University of Technology in Gliwice, and will coordinate work package WP4.
- According to NSAI, wideband AC voltage measurements are needed in telecoms, smart sensors and healthcare technologies, among others, and participation in the project is to translate into calibration services for domestic businesses. Funding comes from the European Partnership on Metrology, co-financed by Horizon Europe and the participating states.