Josephson constant

Josephson constant

[′jō·sef·sən ‚kän·stənt] (physics) The quantity KJ = 2 e/h, which appears in the equations for the alternating-current Josephson effect, where e is the magnitude of the charge of the electron and h is Planck's constant. The conventional value of this quantity adopted by international agreement on January 1, 1990, to establish a standard for the volt, KJ-90= 493,597.9 gigahertz per volt.