Michael Faraday’s breakthrough with electromagnetic induction established the principle behind transformers and generators, helping make large-scale electrical power possible.
THE UNIVERSAL RECORD
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Brad Socha | August 29, 2026 | 9:17 AM EST
On August 29, 1831, Michael Faraday carried out an experiment in the basement laboratory of the Royal Institution in London that demonstrated a fundamental connection between electricity and magnetism. Using an iron ring wrapped with insulated coils of copper wire, he showed that an electric current in one circuit could induce a current in another without the two circuits being electrically connected.
The effect he observed was brief, but its implications were enormous. Faraday had demonstrated electromagnetic induction, a principle that would become fundamental to transformers and electrical generators. Nearly two centuries later, the same underlying physics remains essential to the systems that generate and distribute electricity on a massive scale.
Faraday’s achievement did not emerge from a single isolated experiment. Scientists had spent years investigating the relationship between electricity and magnetism. In 1820, Danish physicist Hans Christian Ørsted demonstrated that an electric current could produce a magnetic effect. The discovery raised an obvious question: could magnetism, in turn, produce electricity?
Faraday pursued that problem intensely.
Faraday Finds the Missing Connection
Faraday’s route into science was unconventional. Born in England in 1791, he received relatively little formal education and became an apprentice bookbinder as a teenager. His access to books helped cultivate an interest in science, and lectures he attended eventually brought him into contact with prominent chemist Humphry Davy. Faraday joined the Royal Institution in 1813 and developed into an accomplished experimental scientist.
By the 1820s, he was already investigating electromagnetism. In 1821, he demonstrated electromagnetic rotation, an early milestone in the development of the electric motor. But producing electricity through magnetism remained elusive.
That changed during an intensive series of experiments in August 1831.
Faraday constructed an iron ring approximately six inches in diameter and wound insulated copper wire around opposite sides. When he connected one coil to a battery, a galvanometer connected to another coil registered a momentary current. When the battery connection changed, the instrument responded again.
A steady current in the first coil did not continuously generate current in the second. Instead, the crucial effect appeared when the electromagnetic conditions changed.
This distinction was fundamental. Faraday had demonstrated what became known as electromagnetic induction: a changing magnetic environment can induce an electromotive force in a conductor.
The surviving ring-coil apparatus remains in the Royal Institution’s collection. The institution describes it as the first electric transformer because electrical energy passed between separate circuits through electromagnetic induction rather than a direct electrical connection.
Faraday continued experimenting. He demonstrated induction using magnets and coils and investigated how motion through a magnetic field could generate electricity. In October 1831, he built an experimental generator in which moving a bar magnet through a coil caused a galvanometer to register current.
Faraday published his findings in the Philosophical Transactions of the Royal Society as part of his Experimental Researches in Electricity, establishing his priority in reporting the discovery.
There is an important historical qualification. American physicist Joseph Henry was independently investigating induction during the same period. Smithsonian Institution records note that both men independently induced electrical currents, but Faraday published his results first. Faraday is therefore generally credited with the 1831 discovery of electromagnetic induction.
From an Iron Ring to the Power Grid
The practical importance of Faraday’s discovery unfolded over decades.
Electromagnetic induction provided the physical foundation for generating electricity mechanically. A generator converts mechanical energy into electrical energy by creating relative motion between conductors and magnetic fields. The source of that mechanical motion can vary dramatically, but the underlying principle remains.
In a hydroelectric station, moving water turns turbines. Wind turbines extract energy from moving air. In many nuclear and fossil-fuel plants, heat ultimately produces steam that rotates turbines. Those turbines drive generators, where electromagnetic induction produces electrical energy.
Faraday’s ring experiment also anticipated the transformer, a device crucial to modern alternating-current power systems. Transformers use electromagnetic induction to transfer electrical energy between circuits and change voltage levels.
That capability became central to large-scale electricity distribution. Power can be transmitted at high voltage to reduce energy losses over long distances and then transformed to lower voltages for regional distribution and eventual use in homes and businesses.
Faraday did not construct the modern electrical grid, nor did his 1831 apparatus resemble the sophisticated generators and transformers operating today. Those technologies resulted from decades of additional discoveries and engineering advances. His contribution was more fundamental: he established the physical principle on which much of that technology depends.
His work also became part of a broader scientific transformation. Later in the 19th century, Scottish physicist James Clerk Maxwell expressed the relationships among electricity, magnetism and electromagnetic fields mathematically. The development of electromagnetic theory helped establish the foundations for technologies ranging from electrical machinery to communications.
Faraday’s name survives directly in physics. The farad, the SI unit of electrical capacitance, was named in his honour.
Yet perhaps the clearest measure of his legacy is less visible. Every time a large generator produces electricity through electromagnetic induction, or a transformer changes voltage as electricity moves through a power network, the principle demonstrated in Faraday’s London laboratory remains at work.
The apparatus that helped reveal it was remarkably modest: an iron ring, copper wire, a battery and an instrument capable of detecting current. On August 29, 1831, those components provided evidence for a relationship between electricity and magnetism that would eventually help power the modern world.
Sources:
Royal Institution — Michael Faraday’s Ring-Coil Apparatus
https://www.rigb.org/explore-science/explore/collection/michael-faradays-ring-coil-apparatus
Royal Institution — Michael Faraday’s Generator
https://www.rigb.org/explore-science/explore/collection/michael-faradays-generator
Royal Institution — Michael Faraday (1791–1867)
https://www.rigb.org/explore-science/explore/person/michael-faraday-1791-1867
Royal Institution — History of Research at the Royal Institution
https://www.rigb.org/explore-science/explore/collection/history-research-ri
American Physical Society — September 4, 1821 and August 29, 1831: Faraday and Electromagnetism
https://www.aps.org/apsnews/2001/08/faraday-electromagnetism
Smithsonian Institution Archives — Electromagnetism
https://siarchives.si.edu/history/featured-topics/henry/electromagnetism
Smithsonian Institution Archives — Henry’s Early Research in Electromagnetism
https://siarchives.si.edu/collections/siris_sic_329
Smithsonian Libraries — Michael Faraday, Terrestrial Magneto-Electric Induction; Force and Direction of Magneto-Electric Induction Generally
https://library.si.edu/digital-library/book/terrestrialmagne00fara
About the Author
Brad Socha is the founder of The Universal Record, focused on sourced, factual global reporting. Coverage includes international news, geopolitics, technology, and major developments.