The standard ampere is most accurately realized using a watt balance, but is in practice maintained via Ohm's Law from the units of electromotive force and resistance, the volt and the ohm, since the latter two can be tied to physical phenomena that are relatively easy to reproduce, the Josephson junction and the quantum Hall effect, respectively.

In a similar way, accurate AC / DC non-contact ammeters have been constructed using Hall effect magnetic field sensors.

This phenomenon arising due to the nature of charge carriers in the conductor came to be known as the Hall effect, but it was not properly explained at the time, since the electron was experimentally discovered 18 years later.

The quantum Hall effect was discovered by Klaus von Klitzing in 1980 when he observed the Hall conductivity to be integer multiples of a fundamental constant.

Shortly after, in 1982, Störmer and Tsui observed the fractional quantum Hall effect where the conductivity was now a rational multiple of a constant.

The study of topological properties of the fractional Hall effect remains an active field of research.

Devices used for this include Hall effect sensors, current clamps, current transformers, and Rogowski coils.

* Hall effect current sensor transducers

In some contexts it is meaningful to speak of fractions of a charge ; for example in the charging of a capacitor, or in the fractional quantum Hall effect.

The quasiparticles of the fractional quantum Hall effect are also known as composite fermions, which are electrons with an even number of quantized vortices attached to them.

The Hall effect is the production of a voltage difference ( the Hall voltage ) across an electrical conductor, transverse to an electric current in the conductor and a magnetic field perpendicular to the current.

The Hall effect was discovered in 1879 by Edwin Herbert Hall while he was working on his doctoral degree at Johns Hopkins University in Baltimore, Maryland.

The Hall effect is due to the nature of the current in a conductor.

This cannot explain the opposite sign of the Hall effect observed.

As a result, the Hall effect is very useful as a means to measure either the carrier density or the magnetic field.

One very important feature of the Hall effect is that it differentiates between positive charges moving in one direction and negative charges moving in the opposite.

The Hall effect offered the first real proof that electric currents in metals are carried by moving electrons, not by protons.

The Hall effect also showed that in some substances ( especially p-type semiconductors ), it is more appropriate to think of the current as positive " holes " moving rather than negative electrons.

The sample inhomogeneity might result in spurious sign of the Hall effect, even in ideal van der Pauw configuration of electrodes.

For example, positive Hall effect was observed in evidently n-type semiconductors.

The Hall effect in an ionized gas ( plasma ) is significantly different from the Hall effect in solids ( where the Hall parameter is always very inferior to unity ).

But now the task is completed and the uncertainty resolved with the opening of the English-dialogue picture at the Music Hall yesterday.

Chabrier's little one-act operetta, presented yesterday afternoon at Town Hall, is a fragile, precious little piece, very French, not without wit and charm.

It is a kind of justice, too, that it should originate in London's Royal Albert Hall, where, traditionally, the loudest, if not the greatest, performers have entertained the thousands it will accommodate ( RCA Victor LM 2454, $4.98 ).

Doubleday Field is a minor league baseball stadium named for Abner Doubleday, located in Cooperstown, New York, near the Baseball Hall of Fame.

* 1924 – Adolf Hitler is sentenced to five years in jail for his participation in the " Beer Hall Putsch ".

" Hall of the Slain " i. e. " the Chosen Ones ") This heavenly abode, somewhat analogous to the Greek Elysium, is reserved for those brave warriors who die heroically in battle.

" The Covered Hall ") This abode is somewhat like Hades from Ancient Greek religion: there, something not unlike the Asphodel Meadows can be found, and people who have neither excelled in that which is good nor excelled in that which is bad can expect to go there after they die and be reunited with their loved ones.

The Residence Hall Association ( RHA ) of Arizona State University is the student government for every ASU student living on-campus.

The original fossil skeleton is assembled and stands in the Hall of Dinosaurs at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania.

Her second and last novel, The Tenant of Wildfell Hall, which is considered to be one of the first sustained feminist novels, appeared in 1848.

Mainly because the re-publication of The Tenant of Wildfell Hall was prevented by Charlotte Brontë after Anne's death, she is less known than her sisters Charlotte, author of four novels including Jane Eyre, and Emily, author of Wuthering Heights.

The War Memorial Hall ( more generally known as Memorial Hall ), which is a residence, and War Memorial Gymnasium

Today, Horton Hall is the home of the Department of Psychology and Research and Graduate Studies.

Emmerson Hall, built in 1913, is particularly interesting for the variety of building stones used.

A memorial pipe organ in Convovation Hall, Acadia University is dedicated to the members of Acadia University killed during the First World War A book of remembrance in Manning Chapel, Acadia University was unveiled on 1 March 1998 through the efforts of the Wolfville Historical Society

Carnegie Hall, built in 1909, is a large, two-storey, Neo-classical brick building on the Registry of Historic Places of Canada

The apartment where this is to have taken place is one of the most beautiful courts of the Alhambra, and is still called the Hall of the Abencerrages.

Various markets are held in the Market Hall, for example: Tuesdays – retail market, which also stretches into the town hall car park and temporarily the Cattle Market, while Brewery Yard car park is regenerated ; Wednesday – flea market ; 4th Thursday of the month a farmers ' market ; Friday – retail market ; Saturday – retail market ( also in the town hall car park ); 3rd Sunday of the month – antique fair ; 2nd Saturday – craft fair.

She also was a great-grandniece of Giovanni Schiaparelli, an Italian astronomer who believed he had discovered the supposed canals of Mars, and a great-grandniece of art expert Bernard Berenson ( 1865 – 1959 ) and his sister Senda Berenson ( 1868 – 1954 ), an athlete and educator who was one of the first two women elected to the Basketball Hall of Fame.

In 1879, Edwin Herbert Hall working at the Johns Hopkins University discovered the development of a voltage across conductors transverse to an electric current in the conductor and magnetic field perpendicular to the current.

It was discovered by Edwin Hall in 1879.

Now 16, Huxley entered Sydenham College ( behind University College Hospital ), a cut-price anatomy school whose founder Marshall Hall discovered the reflex arc.

Phobos was discovered by astronomer Asaph Hall on August 18, 1877, at the United States Naval Observatory in Washington, D. C., at about 09: 14 Greenwich Mean Time ( contemporary sources, using the pre-1925 astronomical convention that began the day at noon, give the time of discovery as August 17 at 16: 06 Washington mean time ).

Hall also discovered Deimos, Mars's other moon, on August 12, 1877 at about 07: 48 UTC.

Asaph Hall, who discovered the moons of Mars, named one Deimos, and the other Phobos.

The National Railway Museum's collection at York includes a commemorative plaque and E. H. Bailey's statue of George Stephenson, both from the Great Hall, the entrance gates and an 1846 LNWR turntable discovered during demolition.

* Superior quantum Hall Effect discovered

Asaph Hall III ( October 15, 1829 – November 22, 1907 ) was an American astronomer who is most famous for having discovered the moons of Mars, Deimos and Phobos, in 1877.

In 1944, while performing at London's Royal Albert Hall, Clark was discovered by film director Maurice Elvey, who cast her as precocious orphaned waif Irma in his weepy war drama Medal for the General.

Feinstein was close by in City Hall at the time of the shootings, and discovered Milk's body after hearing the gunshots and going to investigate.

The New York State Assembly appropriated $ 3 million for the city to buy it, but this fell through when a newspaper reporter discovered that the plan was a graft scheme by Tammany Hall boss Richard Croker.

Moyse's Hall Museum Bury St Edmunds discovered and facilitated the handing over of the collections following a VE Day ( Victory in Europe Day )/ VJ day ( Victory over Japan Day ) exhibition, to which the family had bought Brian's art and other personal artefacts.

In January 2008, construction workers discovered an unexploded Civil War-era " parrott " round shell underneath Arlington Hall.

Hall was staying at a hostel on the French Riviera when she was discovered sunbathing on a Saint Tropez beach by a fashion agent, Claude Haddad.

This Hawkman was Carter Hall, a reincarnation of an ancient Egyptian prince, Khufu, who had in the modern day discovered that the mysterious " ninth metal " could negate the effects of gravity and allow him to fly.

The museum's Great Hall is dominated by the first fossil skeleton of Apatosaurus that he discovered ( but called " Brontosaurus ").