Towards a Quantum Current Standard : a Single Electron Device Connected to a Ccc

The base electrical unit, the ampere, was defined in 1960 and its realization was carried out by means of a Pellat-type balance. This experiment was typically difficult, time consuming and the achieved uncertainty was close to 8.10. As a result, in practice, the realization of electrical units does not start with ampere of which the representation requires the volt and the ohm. Two discoveries in solid physics, Quantum Hall Effect (QHE, level uncertainty of ~10) and Josephson Effect (JE, ~10), have revolutionized the electrical metrology in such a way that today they are used in most national metrology institutes for establishing the reference standard of electrical resistance (Ω) and electromotive force (V). These quantum standards are much better than material representations (standard cells or standard resistors) in terms of stability in time, reproducibility and uncertainty.