Improvements of the programmable quantum current generator for better traceability of electrical current measurements

Abstract

Abstract A programmable quantum current generator based on the application of Ohm’s law to quantum voltage and resistance standards has demonstrated a realization of the ampere from the elementary charge with a 10−8 relative uncertainty (Brun-Picard et al 2016 Phys. Rev. X 6 041051). Here, we report on improvements of the device leading to a noise reduction of the generated quantized current. The improved quantum current generator is used to calibrate different ammeters with lower measurement uncertainties. Besides, measurements of its quantized current using a calibrated ultrastable low-noise current amplifier have shown that the realizations of the ampere at PTB (Physikalisch-Technische Bundesanstalt) and LNE (Laboratoire national de Métrologie et d’essais) in the range ±50 μA agreed to −3.7 parts in 107 with a combined standard uncertainty of 3.1 parts in 107 (coverage factor k c = 1).