It poured out of him like an electric current, a feeling that the muscles and nerves of his fine-drawn body were coiling for action, and that that action would be all that he anticipated.

He devised a detonating fuse in which a short wire was caused to glow by an electric current.

It was with the assistance of one of the members of this expedition, Lauritz Esmarch, that Oersted succeeded in producing light by creating an electric discharge in mercury vapor through which an electric current was made to flow.

For a time following the abandonment of the local plant, electric current for Manchester was brought in from the south with an emergency tie-in with the Vermont Marble Company system to the north.

The ampere ( SI unit symbol: A ), often shortened to amp, is the SI unit of electric current ( quantity symbol: I, i ) and is one of the seven SI base units.

Ampère's force law states that there is an attractive or repulsive force between two parallel wires carrying an electric current.

Category: Units of electric current

The SI unit of measurement of electric current, the ampere, is named after him.

In September of 1820, Ampère ’ s friend and eventual eulogist François Arago showed the members of the French Academy of Sciences the surprising discovery of Danish physicist Hans Christian Ørsted that a magnetic needle is deflected by an adjacent electric current.

In 1800, as the result of a professional disagreement over the galvanic response advocated by Galvani, he invented the voltaic pile, an early electric battery, which produced a steady electric current.

An anode is an electrode through which electric current flows into a polarized electrical device.

The direction of electric current is, by convention, opposite to the direction of electron flow.

In fact anode polarity depends on the device type, and sometimes even in which mode it operates, as per the above electric current direction-based universal definition.

* In a cathode ray tube, it is the positive terminal where electrons flow out of the device, i. e., where positive electric current flows in.

In that paper Faraday explained that when an electrolytic cell is oriented so that electric current traverses the " decomposing body " ( electrolyte ) in a direction " from East to West, or, which will strengthen this help to the memory, that in which the sun appears to move ", the anode is where the current enters the electrolyte, on the East side: " ano upwards, odos a way ; the way which the sun rises " (, reprinted in ).

An ammeter is a measuring instrument used to measure the electric current in a circuit.

The relation between electric current, magnetic fields and physical forces was first noted by Hans Christian Ørsted who, in 1820, observed a compass needle was deflected from pointing North when a current flowed in an adjacent wire.

Earth batteries tap electric currents in the earth called telluric current.

By channeling a large electric current through the compressed carbon granules in the microphone, a small sound signal could produce a much larger electric signal.

In 1808 Davy observed that electric current sent through a solution of borates produced a brown precipitate on one of the electrodes.

In fluid dynamics, the continuity equation is analogous to Kirchhoff's Current Law in electric circuits.

Subsequently, the accelerative force on any given ion is controlled by the electrostatic equation, where n is the ionisation state of the ion, and e is the fundamental electric charge.

Therefore the ion speed can be computed with the following equation, which relates kinetic energy to energy gain due to the electric field.

Equations ( 6 ) and ( 7 ) are equal, so this results in a vector-valued differential equation for the electric field, namely

It can be shown, that, under these conditions, the electric and magnetic fields satisfy the electromagnetic wave equation:

Thus, the conservation of electric charge, as expressed by the continuity equation, gives the result:

Rather than the amount of charge and its velocity in electric and magnetic fields, this equation relates the energy flux ( flow of energy per unit time per unit distance ) in the fields to the force exerted on a charge distribution.

In the 19th century, James Clerk Maxwell showed that, in vacuum, the electric and magnetic fields satisfy the wave equation both with speed equal to that of the speed of light.

The solutions of Laplace's equation are the harmonic functions, which are important in many fields of science, notably the fields of electromagnetism, astronomy, and fluid dynamics, because they can be used to accurately describe the behavior of electric, gravitational, and fluid potentials.

Taking the divergence of the electrostatic field, we obtain Poisson's equation, that relates charge density and electric potential

In the particular case of the empty space () Poisson's equation reduces to Laplace's equation for the electric potential.

The classical sinusoidal plane wave solution of the electromagnetic wave equation for the electric and magnetic fields is

This means that the charge q in the equation above is not the charge that is creating the electric field, but rather, being acted upon by it.

Ignoring such effects, the equation for the magnitude of the electric field E is:

Taking the curl of the electric field equation we obtain,

The classical sinusoidal plane wave solution of the electromagnetic wave equation for the electric and magnetic fields is ( cgs units )

A mathematical expression for its complex electric field amplitude can be found by solving the paraxial Helmholtz equation, yielding

The classical sinusoidal plane wave solution of the electromagnetic wave equation for the electric and magnetic fields is ( cgs units )

with the element of path along the integration of electric field vector E. If the applied E field is uniform and oriented along the length of the conductor as shown in the figure, then defining the voltage V in the usual convention of being opposite in direction to the field ( see figure ), and with the understanding that the voltage V is measured differentially across the length of the conductor allowing us to drop the Δ symbol, the above vector equation reduces to the scalar equation:

The equation given above for the electric potential ( and all the equations used here ) are in the forms required by SI units.

The most famous example is the non-relativistic Schrödinger equation for a single particle moving in an electric field ( but not a magnetic field ):

As before, the most famous manifestation is the non-relativistic Schrödinger equation for a single particle moving in an electric field ( but not a magnetic field ):

Normally wave equations in physics can be derived from other physical laws-the wave equation for mechanical vibrations on strings and in matter can be derived from Newton's laws-where the analogue wavefunction is the displacement of matter, and electromagnetic waves from Maxwell's equations, where the wavefunctions are electric and magnetic fields.