Editing Inductance (section)

== History ==
{{main|History of electromagnetic theory}}
The history of electromagnetic induction, a facet of [[electromagnetism]], began with observations of the ancients: electric charge or static electricity (rubbing silk on [[amber]]), electric current ([[lightning]]), and magnetic attraction ([[lodestone]]). Understanding the unity of these forces of nature, and the scientific theory of electromagnetism was initiated and achieved during the 19th century.

Electromagnetic induction was first described by [[Michael Faraday]] in 1831.<ref>{{cite book |last=Ulaby |first=Fawwaz |title=Fundamentals of applied electromagnetics |edition=5th |year=2007 |url=https://books.google.com/books?id=-1GDkgEACAAJ|publisher=Pearson / Prentice Hall |isbn=978-0-13-241326-8 |page=255}}</ref><ref>{{cite web |url=http://www.nas.edu/history/members/henry.html |title=Joseph Henry |access-date=2006-11-30 |work=Distinguished Members Gallery, National Academy of Sciences |url-status=dead |archive-url=https://web.archive.org/web/20131213121232/http://www.nas.edu/history/members/henry.html |archive-date=2013-12-13 }}</ref> In Faraday's experiment, he wrapped two wires around opposite sides of an iron ring. He expected that, when current started to flow in one wire, a sort of wave would travel through the ring and cause some electrical effect on the opposite side. Using a [[galvanometer]], he observed a transient current flow in the second coil of wire each time that a battery was connected or disconnected from the first coil.<ref>{{cite book|isbn=9780671209292|pages=182–183|title=Michael Faraday: A Biography |last1=Pearce Williams |first1=L. |year=1971 |publisher=Simon and Schuster }}</ref> This current was induced by the change in [[magnetic flux]] that occurred when the battery was connected and disconnected.<ref name=Giancoli>{{cite book |last=Giancoli |first=Douglas C. |title=Physics: Principles with Applications |url=https://archive.org/details/physicsprinciple00gian |url-access=registration |year=1998 |pages=[https://archive.org/details/physicsprinciple00gian/page/623 623–624] |edition=Fifth}}</ref> Faraday found several other manifestations of electromagnetic induction. For example, he saw transient currents when he quickly slid a bar magnet in and out of a coil of wires, and he generated a steady ([[direct current|DC]]) current by rotating a copper disk near the bar magnet with a sliding electrical lead ("[[Homopolar generator|Faraday's disk]]").<ref>{{cite book|isbn=9780671209292|pages=191–195|title=Michael Faraday: A Biography |last1=Pearce Williams |first1=L. |year=1971 |publisher=Simon and Schuster }}</ref>