Editing Electric current (section)

===Reference direction===
A current in a wire or [[circuit element]] can flow in either of two directions.  When defining a [[variable (mathematics)|variable]] <math>I</math> to represent the current, the direction representing positive current must be specified, usually by an arrow on the [[Circuit diagram|circuit]] [[schematic diagram]].<ref name="Kumar">{{cite book  
  | last = Kumar
  | first = K. S. Suresh
  | title = Electric Circuits & Networks
  | publisher = Pearson Education India
  | year = 2008
  | location =
  | pages = 26–28
  | url = https://books.google.com/books?id=ZzeXM-IQnIUC&pg=PA278
  | doi =
  | id =
  | isbn = 978-8131713907}}</ref><ref name="Hayt5">{{Cite book |last=Hayt |first= William |year= 1989 |title= Engineering Electromagnetics |edition= 5th |publisher= McGraw-Hill |isbn= 0070274061}}</ref>{{rp|13}}  This is called the ''reference direction'' of the current <math>I</math>.  When [[Circuit Analysis|analyzing electrical circuits]], the actual direction of current through a specific circuit element is usually unknown until the analysis is completed. Consequently, the reference directions of currents are often assigned arbitrarily. When the circuit is solved, a negative value for the current implies the actual direction of current through that circuit element is opposite that of the chosen reference direction.{{efn| Our first step in the analysis is the assumption of reference directions for the unknown currents.<ref name="Hayt5"></ref>}}{{rp|29}}