Name: hall voltage and charge carriers
Uploaded: 2025-05-22T09:05:51.000Z
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K12 Standards

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North Carolina K-12 Science Standard Course of Study

9-12

Physical Science

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Motion and Stability- Forces and Interactions

PS.PSc.6.4

The Hall Effect

Rozważmy prostokątny przewodnik przewodzący prąd z elektronami jako nośnikami ładunku. Kiedy pole magnetyczne jest przyłożone prostopadle do płaszczyzny przewodnika, elektrony poruszające się w linii prostej dryfują z powodu odchylającej siły magnetycznej.
Elektrony gromadzą się po jednej stronie przewodnika, pozostawiając nadmiar ładunków dodatnich po drugiej stronie. Ta separacja ładunków wytwarza pole elektryczne w przewodniku, które wywiera siłę elektryczną na każdy elektron przeciwny sile magnetycznej.
W stanie równowagi wielkość siły elektrycznej równoważy siłę magnetyczną, zatrzymując dalsze dryfowanie elektronów. Różnica potencjałów między dwiema stronami przewodu to napięcie halla.
Wyrażając prędkość dryftu w postaci prądu, napięcie Halla można również wykorzystać do pomiaru gęstości liczbowej nośników ładunku.
Sondy Halla mierzą wielkość nieznanego pola magnetycznego na podstawie napięcia Halla i znanych parametrów przewodnika.
Znaczącym zastosowaniem tego odkrycia jest to, że polaryzacja napięcia Halla implikuje, czy nośniki ładunku w przewodniku są ujemne czy dodatnie.

<ol>
	<li>Protokół OpenStax. (2019). Fizyka uniwersytecka Vol. 2. [Wersja internetowa]. Pobrano z 514-516 <a href="https://openstax.org/books/university-physics-volume-2/pages/11-6-the-hall-effect">https://openstax.org/books/university-physics-volume-2/pages/11-6-the-hall-effect</a></li>
</ol>

efekt halla

Edwin H. Hall w roku 1879 obmyślił eksperyment, który można wykorzystać do określenia polaryzacji głównych nośników ładunku w materiale przewodzącym. Z historycznego punktu widzenia ten eksperyment jako pierwszy wykazał, że nośniki ładunku w większości metali są ujemne.

<img alt="Figure1" src="/files/ftp_upload/13772/13772_Figure_1.png" style="text-align: center" />

Rozważmy metalową płytę o szerokości L umieszczoną w stałym polu magnetycznym. Elektrony poruszają się od prawej do lewej, więc działająca na nie siła magnetyczna wypycha je w stronę górnej krawędzi płyty. Pozostawia to nadmiar ładunku ujemnego na górnej krawędzi płyty i nadmiar ładunku dodatniego na dolnej krawędzi płyty, co skutkuje polem elektrycznym skierowanym od dołu do góry. Stężenie ładunku na obu krawędziach rośnie, aż do ustalenia stanu równowagi. W stanie równowagi siła elektryczna działająca na elektrony w jednym kierunku jest równoważona przez siłę magnetyczną w przeciwnym kierunku. Ten scenariusz, w którym pola elektryczne i magnetyczne są do siebie prostopadłe, nazywany jest sytuacją pola skrzyżowanego.

Prąd w płycie I można zapisać jako prędkość dryfu, vd i pole przekroju poprzecznego płyta, A. Różnica potencjałów pomiędzy krawędziami paska, zwana inaczej napięciem Halla, jest określona przez,

<img alt="Równanie1" src="/files/ftp_upload/13772/13772_Equation_1.png" style="text-align: center; height: 40px;" />

Polaryzacja napięcia Halla pokazuje, czy nośniki ładunku są dodatnie, czy ujemne. Innym ważnym zastosowaniem tego efektu są materiały o znanej gęstości nośników ładunku. Zmierzone napięcie Halla może dać wartość nieznanego pola magnetycznego. W laboratoriach badawczych, w których pola elektromagnesów używanych do precyzyjnych pomiarów muszą być bardzo stabilne, stosowana jest sonda Halla. jest powszechnie używany jako część obwodu elektronicznego do regulacji pola.

Efekt Halla

Edwin H. Hall w roku 1879 opracował eksperyment, który można było wykorzystać do zidentyfikowania biegunowości dominujących nośników ładunku w przewodzie ...

Education

JoVE Core

Physics

Fizyka

Unit 1

Jednostka 1

Magnetic Forces and Fields

Siły i pola magnetyczne

KEY TERMS AND CONCEPTS

Kluczowe terminy i pojęcia

hall voltage and charge carriers

Hall voltage and charge carriers are explained through Edwin H. Hall’s 1879 experiment. His setup helped identify the polarity of the main charge carriers in a conducting material. It also showed, for the first time, that the charge carriers in most metals are negative.

A metal slab is placed in a constant magnetic field. The electrons move from right to left, so the magnetic force pushes them toward the top edge of the slab. This leaves excess negative charge at the top and excess positive charge at the bottom. As a result, an electric field forms from the bottom edge to the top edge.

The charge buildup continues until equilibrium is reached. At that point, the electric force on the electrons balances the magnetic force in the opposite direction. This is called a crossed-field situation because the electric and magnetic fields are perpendicular to each other. The current in the slab, I, can be written in terms of the drift velocity, v d, and the cross-sectional area, A.

The potential difference between the two edges is called the Hall voltage. Its polarity reveals whether the charge carriers are positive or negative. When the density of charge carriers is known, the Hall voltage can also be used to find an unknown magnetic field. In research labs, a Hall probe is often used in electronic circuits to help regulate electromagnet fields so they stay steady for precise measurements.

Hall Voltage and Charge Carriers

magnetism

Magnetic Poles and Everyday Uses

Magnetism appears in many everyday objects, from toys and hangers to elevators, doorbells, and computer devices. Magnets have two poles, called north and south. Like poles repel each other, while unlike poles attract. Both poles can also attract unmagnetized iron. A single magnetic pole cannot be isolated, because every part of a magnet contains both a north pole and a south pole. A compass needle is a simple example of a magnet. It is a thin bar magnet suspended at its center, so it can turn...

magnetic fields

Magnetic Force on Moving Charges

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magnetic field lines

Reading Magnetic Field Lines

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motion of a charged particle in a magnetic field

motion-of-a-charged-particle-in-a-magnetic-field

Charged Particle Paths in Magnetic Fields

A charged particle in a magnetic field follows a path that depends on the direction of its velocity. When the field is uniform and the particle moves perpendicular to it, the magnetic field is the main factor that controls the motion, especially in a vacuum. The magnetic force is always perpendicular to the direction of motion, so the particle curves into a circle. Because the force stays perpendicular to velocity, it does no work on the particle. The kinetic energy and speed stay constant...

magnetic force

Magnetic Fields and Moving Charges

Magnetic fields and moving charges create magnetic force. A moving electric charge, or a current made of many moving charges, produces a magnetic field. When another current or moving charge enters that field, it feels a magnetic force in response. At the atomic level, magnetic forces come from interactions between moving electrons in the atoms of two bodies. The strength of magnetic force depends on several factors. It increases with the size of the charge and with the strength of the...

magnetic force on a current-carrying conductor

magnetic-force-on-a-current-carrying-conductor

Current and Magnetic Field Around a Wire

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magnetic force on current-carrying wires: example

magnetic-force-on-current-carrying-wires-example

Balancing Weight with Magnetic Force

Magnetic force can balance the weight of a current-carrying wire when the wire sits in a magnetic field. Moving charges in the wire feel a force, so the wire itself can be pushed upward or downward. This example uses a flexible wire that is 40 cm long and has a mass of 10 g. It is held in a horizontal position inside a constant 0.40 T magnetic field. The goal is to find the current needed to remove the tension in the supporting leads. To do that, a free-body diagram is drawn first. The diagram...

force on a current loop in a magnetic field

force-on-a-current-loop-in-a-magnetic-field

Current Loops and Torque in Motors

Current loops in a magnetic field create the torque that drives a DC motor. A DC motor converts electrical energy into mechanical work. In a motor, wire loops sit inside a magnetic field. When current flows through the loops, the magnetic field pushes on them and makes the shaft rotate. The current is reversed when the loop lines up with the magnetic field. This keeps the torque on the loop going in the same direction. A commutator and brushes handle this reversal. The commutator switches the...

torque on a current loop in a magnetic field

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Current Loop Torque in Electric Motors

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the hall effect

Hall voltage and charge carriers are explained through Edwin H. Hall’s 1879 experiment. His setup helped identify the polarity of the main charge carriers in a conducting material. It also showed, for the first time, that the charge carriers in most metals are negative. A metal slab is placed in a constant magnetic field. The electrons move from right to left, so the magnetic force pushes them toward the top edge of the slab. This leaves excess negative charge at the top and excess positive...

thomson's e/m experiment

Electron Speed Selector in Thomson’s Tube

A velocity selector uses electric and magnetic fields to choose charged particles with one speed from a beam. Many beams from a heated cathode contain particles moving at different speeds, so this setup helps produce a uniform beam. The electric and magnetic fields are perpendicular to the particle’s motion and to each other. In this arrangement, a particle with charge q, speed v, and mass m enters from the top. The magnetic field points into the plane of the paper, and the electric field...

key terms and concepts

Learn how Hall voltage forms in a magnetic field, how it reveals charge carrier polarity, and how Hall probes help measure and control magnetic fields.

Hall Voltage and Charge Carriers | JoVE K12

physics

JoVE Core Physics introduces the theory and application of fundamental physics topics, including kinematics, dynamics, fluid mechanics, statics, waves, and acoustics, with concise and easy-to-understand animated videos. Additionally, the scientist-in-action videos demonstrate the application of related concepts in classical and original research experiments performed in today's laboratories worldwide.

Virginia  Standards of Learning

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PS.9

PS.9.d

Alabama Course of Study Science

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Waves and Their Applications in Technologies for Information Transfer

9-12.PS.2.3.b

Position and Displacement

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Average Velocity

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Instantaneous Velocity - I

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Instantaneous Velocity - II

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Average Acceleration

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Instantaneous Acceleration

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Analyze and interpret data to explain the motion of an object moving with a constant velocity or that is accelerating.

PS.PSc.4.1

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Drift Velocity

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Current Density

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Resistivity

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Resistance

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Ohm's Law

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Non-ohmic Devices

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Construct an explanation to compare simple series and parallel circuits in terms of Ohm's Law.

PS.PSc.6.2

Continuity Equation

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Boundary Conditions for Current Density

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PS.PSc.6.3

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magnetic-force-between-two-parallel-currents

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To evaluate the divergence of the ...

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Lenz's Law

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Motional Emf

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Faraday Disk Dynamo

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Induced Electric Fields

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Induced Electric Fields: Applications

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PS.PSc.6.5

Analyze motion in terms of speed, velocity, acceleration, and momentum.

Hall Voltage and Charge Carriers

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