Thanks,
All I know is that it is linked to the quantum Hall effect and is used in a Watt balance that is then used to measure the current. It uses the Von klitzing constant to measure the resistance but I just don't undertand how it works. I don't exactly need all the gritty details as a whole...
How is the constant used to measure resistance? I can't find a clear answer anywhere. The constant is h/e^2 but that doesn't really help in seeing how it is linked to resistance other than the units being the same in base units.