Faraday, Maxwell and Tesla: Who Did What in Electromagnetism?

Three names show up whenever people ask who “invented” electricity and magnetism as a unified subject: Michael Faraday, James Clerk Maxwell and Nikola Tesla. They worked in different decades and on different kinds of problems. Faraday made induction a reproducible experiment. Maxwell wrote a field theory that implied light is an electromagnetic wave. Tesla patented a practical alternating-current motor. None of them alone is the whole of electromagnetism — and several popular stories about them are either oversimplified or simply unsupported.

What did Faraday actually establish?

In 1831 Faraday showed that a changing magnetic environment can drive an electric current in a circuit — electromagnetic induction (Britannica, Faraday^[1]; MacTutor, Faraday^[2]). The modern textbook statement is Faraday’s law: the electromotive force around a loop equals the negative rate of change of magnetic flux through it,

ℰ = −dΦ_B/dt

Britannica’s induction entry summarises that law and its place in Maxwell’s later equations (Britannica, Faraday’s law^[3]). Faraday’s own laboratory narrative is in Experimental Researches in Electricity, available in open digital editions (Faraday, Experimental Researches^[4]). He was not inventing “electricity” from nothing: Ørsted’s 1820 observation that a current deflects a compass needle had already linked electricity and magnetism experimentally (APS News, Ørsted 1820^[5]). Faraday’s contribution was to make induction a systematic, quantitative experimental programme.

What did Maxwell add in 1865?

Maxwell’s memoir “A Dynamical Theory of the Electromagnetic Field,” published in the Philosophical Transactions in 1865, cast Faraday’s lines of force into a mathematical field theory (Maxwell 1865, Wikisource^[6]; Crossref confirms DOI 10.1098/rstl.1865.0008 for Maxwell 1865). An open scan of the memoir is also on Internet Archive (Internet Archive, Maxwell memoir^[7]). MacTutor notes Maxwell’s mathematical formulation of Faraday’s ideas and the prediction that electromagnetic disturbances propagate at about the speed of light (MacTutor, Maxwell^[8]; Britannica, Maxwell^[9]).

In modern vector form the vacuum Maxwell equations include

∇ × E = −∂B/∂t   and   ∇ × B = μ₀ε₀ ∂E/∂t

(plus Gauss’s laws for E and B). The second term — displacement current — is what lets a changing electric field source magnetism even without a conduction current, and together the curl equations yield wave equations with speed 1/√(μ₀ε₀) = c. That is Maxwell’s theoretical bridge from laboratory induction to light. Our pillar How Are Electricity and Magnetism Connected? and the supporting post Why Does a Magnet Fall Slowly Through a Copper Pipe? follow that chain into Lenz’s law.

What did Tesla contribute — and what did he not?

Tesla’s documented contribution to power systems includes U.S. Patent 381,968 (1888) for an “Electro-magnetic motor” — a polyphase AC design (US Patent 381,968^[10]). Britannica summarises his AC power work and notes that he held more than a hundred U.S. patents (Britannica, Tesla^[11]). That is engineering and invention on the delivery of electrical energy, not the foundation of field theory.

What stays carefully limited here: claims that Tesla “discovered AC,” “defeated Edison single-handedly,” or anticipated radio, X-rays or wireless power in forms that match modern technology are often later myth-making. Edison’s DC distribution and Westinghouse’s AC systems were commercial and technical contests with many engineers; Faraday and Maxwell’s physics do not hang on who won which contract. We stick to the patent and the encyclopaedia biography above rather than viral timelines.

Who did what, in one table

• Faraday (1831 and after): experimental induction; flux rule; lines of force as a working picture.
• Maxwell (1865): dynamical field theory; prediction that light is electromagnetic.
• Tesla (1880s patents): practical AC motor and polyphase system designs — application, not the 1865 theory.

Wear the three turns on Faraday, Maxwell and Tesla, or the field characters Spark Herald and Magnetron Twins. Browse Electromagnetism and Physicist Stickers.

How do the three layers show up in a modern lab?

A first-year experiment still repeats Faraday’s insight: move a magnet through a coil and a galvanometer kicks. The same minus sign that is Lenz’s law appears when a neodymium magnet crawls through a copper pipe — eddy currents fight the fall, which we unpack in the copper-pipe post. Maxwell’s layer is harder to see directly, but radio, light and every electromagnetic wave are the 1865 prediction made mundane: once the field equations admit waves at speed c, Hertz’s later sparks were confirmation of a theory already on paper (MacTutor, Maxwell^[8]; Britannica, Maxwell^[9]).

Tesla’s layer is the power engineer’s: polyphase AC lets you send energy with lower losses over long lines than the DC neighbourhood systems of the 1880s, which is why patent US 381,968 matters as a machine design (Tesla patent^[10]). BBC’s short Faraday biography and MacTutor’s Faraday entry both stress the experimental, not commercial, character of Faraday’s own career (BBC Faraday^[12]; MacTutor Faraday^[2]). Keeping those layers separate stops the story from collapsing into a single “inventor of electricity” myth.

What we refuse to claim

We do not claim Tesla secretly invented the smartphone, that Edison “stole” AC from Tesla as a courtroom cartoon, or that Faraday wrote Maxwell’s equations in prose. Faraday’s Experimental Researches are experimental narratives (Gutenberg Faraday^[4]); Maxwell’s memoir is the dynamical theory (Wikisource Maxwell 1865^[6]; Archive.org Maxwell^[7]). Ørsted’s 1820 compass deflection remains the earlier electricity–magnetism bridge (APS Ørsted^[5]). Credit is a stack, not a throne.

FAQ

Did Faraday invent Maxwell’s equations?

No. Faraday supplied the experimental induction law and a physical picture of fields. Maxwell wrote the dynamical theory that unified them with light.

Is Tesla the “father of electricity”?

That label is marketing, not history. Electricity and magnetism as laboratory science run through Ørsted, Ampère, Faraday, Maxwell and many others; Tesla’s documented strength is AC machinery and patents such as US 381,968.

Where does Lenz’s law fit?

Lenz’s law is the direction rule for induced currents (opposing the change in flux). It is the minus sign in Faraday’s law, treated in our copper-pipe post Lenz’s law in a copper pipe.

References

1. Encyclopaedia Britannica, “Michael Faraday” (archived). https://web.archive.org/web/20231220211154/https://www.britannica.com/biography/Michael-Faraday
2. MacTutor History of Mathematics, “Michael Faraday”. https://mathshistory.st-andrews.ac.uk/Biographies/Faraday/
3. Encyclopaedia Britannica, “Faraday’s law of induction” (archived). https://web.archive.org/web/20240102080714/https://www.britannica.com/science/Faradays-law-of-induction
4. M. Faraday, Experimental Researches in Electricity, Vol. 1 (Project Gutenberg). https://www.gutenberg.org/ebooks/14986
5. APS News, “July 1820: Oersted & Electromagnetism” (archived). https://web.archive.org/web/20220301000000/https://www.aps.org/apsnews/2008/07/1820-oersted-electromagnetism
6. J. C. Maxwell (1865), “A Dynamical Theory of the Electromagnetic Field,” Wikisource (Phil. Trans. R. Soc. 155, 459–512). https://en.wikisource.org/wiki/A_Dynamical_Theory_of_the_Electromagnetic_Field
7. J. C. Maxwell, A Dynamical Theory of the Electromagnetic Field (Internet Archive scan of the 1865 memoir). https://archive.org/details/dynamicaltheoryo00maxw
8. MacTutor History of Mathematics, “James Clerk Maxwell”. https://mathshistory.st-andrews.ac.uk/Biographies/Maxwell/
9. Encyclopaedia Britannica, “James Clerk Maxwell” (archived). https://web.archive.org/web/20231202041613/https://www.britannica.com/biography/James-Clerk-Maxwell
10. US Patent 381,968, N. Tesla, “Electro-magnetic motor” (1888). https://patents.google.com/patent/US381968A/en
11. Encyclopaedia Britannica, “Nikola Tesla” (archived). https://web.archive.org/web/20231207001842/https://www.britannica.com/biography/Nikola-Tesla
12. BBC History, “Michael Faraday (1791–1867)”. https://www.bbc.co.uk/history/historic_figures/faraday_michael.shtml

Written by Pixelated Physics. Every factual claim is linked to the source we checked; points that are still debated are labelled open.