4. Conclusion

The measurement of direct current voltage is a cornerstone of electrical metrology and a cross-cutting issue for many scientific, industrial, and technological fields. An examination of opposition methods and voltmetric methods reveals that each approach has its strengths and limitations: the former offer extremely low measurement uncertainties by relying on quantum or semiconductor references, while the latter prioritize ease of use and speed, at the expense of slightly lower accuracy.

The diversity of the devices described – —including Josephson junctions, Zener diode references, calibrators, potentiometric bridges, and digital voltmeters – —illustrates the evolution of measurement techniques, driven by the pursuit of stability, reliability, and traceability. The introduction of quantum references, in particular, has made it possible to anchor the measurement...