The principle of reciprocity

The circumstances surrounding the realisation that NMR signal reception could be quantified in a simple fundamental manner using Lorentz\u2019s Principle of Reciprocity are described. The poor signal-to-noise ratio of the first European superconducting magnet is identified as a major motivating factor, together with the author\u2019s need to understand phenomena at a basic level. A summary is then given of the thought processes leading to the very simple pseudo-static formula that has been the basis of signal-to-noise calculations for over a generation.Peer reviewed: YesNRC publication: Ye