In electrochemistry, Faraday efficiency (also called faradaic efficiency, faradaic yield, coulombic efficiency or current efficiency) describes the efficiency with which charge (electrons) is transferred in a system facilitating an electrochemical reaction.  The word "Faraday" in this term has two interrelated aspects: first, the historic unit for charge is the faraday (F), but has since been replaced by the coulomb (C); and secondly, the related Faradays constant () correlates charge with moles of matter and electrons (amount of substance).  This phenomenon was originally understood through Michael Faradays work and expressed in his laws of electrolysis.