Current comparator for both AC and DC ratio measurements with 10-8-level accuracy

TL;DR

This paper introduces a compact, room-temperature AC/DC current comparator with 10-8 accuracy using diamond-based magnetometry, unifying AC and DC measurements and surpassing traditional methods in precision and simplicity.

Contribution

The work presents the first integrated, cryogenics-free current comparator that combines AC and DC measurement capabilities with high accuracy using diamond NV centers.

Findings

Achieves 10-8 accuracy for both AC and DC signals.

Supports a bandwidth up to 300 Hz.

Operates at room temperature without cryogenics.

Abstract

Accurate measurements of alternating current (AC) and direct current(DC) ratios are fundamental to electric power metrology. However, conventional current comparators for AC and DC typically rely on distinct technologies-electromagnetic induction for AC and superconducting quantum interference devices for DC. This technological divide leads to a fragmented and complex traceability system. Bridging this gap is critical for developing unified current standards that meet the demands of emerging power technologies. In this work, we present a compact, room-temperature AC/DC current comparator that integrates a diamond-based magnetometer using nitrogen-vacancy centers. The device achieves an accuracy of 10-8 for both AC and DC signals and supports a system bandwidth up to 300 Hz, without the need for cryogenics. It surpasses the performance of typical AC comparators, offering ten-fold higher accuracy, and matches that of state-of-the-art DC comparators. This unified, cryogenics-free solution not only enhances precision and versatility but also expands the applicability of the system to DC resistance bridges in quantum electrical standards.