return path

return path (plural return paths)

1. (electricity) The route by which a current or signal returns to its source, or to earth.
   • 2012, Andrew Martin, Underground Overground: A passenger's history of the Tube, Profile Books, →ISBN, page 136:

     The inner, or negative, rail is also known as the 'current return' rail, because electrical current needs a circuit - a return path to earth, in other words.

   • 2023 November 15, Prof. Jim Wild, “This train was delayed because of bad weather in space”, in RAIL, number 996, pages 30-31:

     One rail (known as the traction return rail) is not broken into [track circuit] sections as it provides the return path for the current.

• “return path”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.