The discovery of the quantum effects of Josephson, of Hall, and then of Likharev, allowed one to connect voltage, resistance and current, accordingly, with the following fundamental physical constants (FPhC): Planck's constant h and charge of an electron e, have unclosed perspectives of an essential heightening of the reproducible accuracy of electrical units. Searching the paths of realization accuracy increase went in two directions: the direct one, which consists in the use of the so-called effect of single-electron tunneling (Likharev's effect), and the "roundabout" way through volts and ohm, which are implemented through the quantum effects of Josephson and Hall.