Lightning and urban lighting are some of the most dramatic effects of electricity
Faraday's experiment showing induction between coils of wire: The liquid battery (right) provides a current which flows through the small coil (A), creating a magnetic field. When the coils are stationary, no current is induced. But when the small coil is moved in or out of the large coil (B), the magnetic flux through the large coil changes, inducing a current which is detected by the galvanometer (G).
Thales, the earliest known researcher into electricity
A diagram of Faraday's iron ring apparatus. The changing magnetic flux of the left coil induces a current in the right coil.
Benjamin Franklin conducted extensive research on electricity in the 18th century, as documented by Joseph Priestley (1767) History and Present Status of Electricity, with whom Franklin carried on extended correspondence.
Faraday's disk, the first electric generator, a type of homopolar generator.
Michael Faraday's discoveries formed the foundation of electric motor technology
Alternating electric current flows through the solenoid on the left, producing a changing magnetic field. This field causes, by electromagnetic induction, an electric current to flow in the wire loop on the right.
Charge on a gold-leaf electroscope causes the leaves to visibly repel each other
Faraday's homopolar generator. The disc rotates with angular rate {{mvar|ω}}, sweeping the conducting radius circularly in the static magnetic field {{math|B}} (which direction is along the disk surface normal). The magnetic Lorentz force {{math|v × B}} drives a current along the conducting radius to the conducting rim, and from there the circuit completes through the lower brush and the axle supporting the disc. This device generates an emf and a current, although the shape of the "circuit" is constant and thus the flux through the circuit does not change with time.
An electric arc provides an energetic demonstration of electric current
A wire (solid red lines) connects to two touching metal plates (silver) to form a circuit. The whole system sits in a uniform magnetic field, normal to the page. If the abstract path {{math|∂Σ}} follows the primary path of current flow (marked in red), then the magnetic flux through this path changes dramatically as the plates are rotated, yet the emf is almost zero. After Feynman Lectures on Physics {{Rp|ch17}}
Field lines emanating from a positive charge above a plane conductor
A pair of AA cells. The + sign indicates the polarity of the potential difference between the battery terminals.
Magnetic field circles around a current
The electric motor exploits an important effect of electromagnetism: a current through a magnetic field experiences a force at right angles to both the field and current
Italian physicist Alessandro Volta showing his "battery" to French emperor Napoleon Bonaparte in the early 19th century.
A basic electric circuit. The voltage source V on the left drives a current I around the circuit, delivering electrical energy into the resistor R. From the resistor, the current returns to the source, completing the circuit.
Surface mount electronic components
Early 20th-century alternator made in Budapest, Hungary, in the power generating hall of a hydroelectric station (photograph by Prokudin-Gorsky, 1905–1915).
Wind power is of increasing importance in many countries
The light bulb, an early application of electricity, operates by Joule heating: the passage of current through resistance generating heat
The electric eel, Electrophorus electricus

It is the fundamental operating principle of transformers, inductors, and many types of electrical motors, generators and solenoids.

- Faraday's law of induction

Further analysis of this process, known as electromagnetic induction, enabled him to state the principle, now known as Faraday's law of induction, that the potential difference induced in a closed circuit is proportional to the rate of change of magnetic flux through the loop.

- Electricity
Lightning and urban lighting are some of the most dramatic effects of electricity

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Faraday c. undefined 1857

Michael Faraday

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English scientist who contributed to the study of electromagnetism and electrochemistry.

English scientist who contributed to the study of electromagnetism and electrochemistry.

Faraday c. undefined 1857
Portrait of Faraday in his late thirties, ca. 1826
Michael Faraday, c. 1861, aged about 70
Three Fellows of the Royal Society offering the presidency to Faraday, 1857
Michael Faraday's grave at Highgate Cemetery, London
Equipment used by Faraday to make glass on display at the Royal Institution in London
Electromagnetic rotation experiment of Faraday, ca. 1821
One of Faraday's 1831 experiments demonstrating induction. The liquid battery (right) sends an electric current through the small coil (A). When it is moved in or out of the large coil (B), its magnetic field induces a momentary voltage in the coil, which is detected by the galvanometer (G).
A diagram of Faraday's iron ring-coil apparatus
Built in 1831, the Faraday disk was the first electric generator. The horseshoe-shaped magnet (A) created a magnetic field through the disk (D). When the disk was turned, this induced an electric current radially outward from the center toward the rim. The current flowed out through the sliding spring contact m, through the external circuit, and back into the center of the disk through the axle.
Faraday (right) and John Daniell (left), founders of electrochemistry.
Faraday holding a type of glass bar he used in 1845 to show magnetism affects light in dielectric material.
Michael Faraday meets Father Thames, from Punch (21 July 1855)
Lighthouse lantern room from mid-1800s
Faraday's apparatus for experimental demonstration of ideomotor effect on table-turning
Faraday delivering a Christmas Lecture at the Royal Institution in 1856.
Statue of Faraday in Savoy Place, London. Sculptor John Henry Foley RA.
Plaque erected in 1876 by the Royal Society of Arts at 48 Blandford Street, Marylebone, London
Chemische Manipulation, 1828
Michael Faraday in his laboratory, c. 1850s.
Michael Faraday's study at the Royal Institution.
Michael Faraday's flat at the Royal Institution.
Artist Harriet Jane Moore who documented Faraday's life in watercolours.
Portrait of Faraday in 1842 by Thomas Phillips

His inventions of electromagnetic rotary devices formed the foundation of electric motor technology, and it was largely due to his efforts that electricity became practical for use in technology.

His demonstrations established that a changing magnetic field produces an electric field; this relation was modelled mathematically by James Clerk Maxwell as Faraday's law, which subsequently became one of the four Maxwell equations, and which have in turn evolved into the generalization known today as field theory.

U.S. NRC image of a modern steam turbine generator (STG).

Electric generator

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Device that converts motive power into electric power for use in an external circuit.

Device that converts motive power into electric power for use in an external circuit.

U.S. NRC image of a modern steam turbine generator (STG).
Early Ganz Generator in Zwevegem, West Flanders, Belgium
The Faraday disk was the first electric generator. The horseshoe-shaped magnet (A) created a magnetic field through the disk (D). When the disk was turned, this induced an electric current radially outward from the center toward the rim. The current flowed out through the sliding spring contact m, through the external circuit, and back into the center of the disk through the axle.
Hippolyte Pixii's dynamo. The commutator is located on the shaft below the spinning magnet.
This large belt-driven high-current dynamo produced 310 amperes at 7 volts. Dynamos are no longer used due to the size and complexity of the commutator needed for high power applications.
Ferranti alternating current generator, c. 1900.
A small early 1900s 75 kVA direct-driven power station AC alternator, with a separate belt-driven exciter generator.
The Athlone Power Station in Cape Town, South Africa
Hydroelectric power station at Gabčíkovo Dam, Slovakia
Hydroelectric power station at Glen Canyon Dam, Page, Arizona
Mobile electric generator
Protesters at Occupy Wall Street using bicycles connected to a motor and one-way diode to charge batteries for their electronics

Before the connection between magnetism and electricity was discovered, electrostatic generators were invented.

The principle, later called Faraday's law, is that an electromotive force is generated in an electrical conductor which encircles a varying magnetic flux.