Name: faraday disk dynamo and dc output
Uploaded: 2023-09-18T17:11:16.000Z
Duration: 1 min 23 s
Channel: JoVE

K12 Standards

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North Carolina K-12 Science Standard Course of Study

9-12

Physical Science

motion-and-stability-forces-and-interactions

Motion and Stability- Forces and Interactions

PS.PSc.6.5

Faraday Disk Dynamo

O dínamo de disco de Faraday é um gerador de corrente contínua que funciona com base no princípio da indução.
Consiste em um disco condutor girando com uma velocidade angular constante por meio de um eixo condutor, que é colocado em um campo magnético uniforme perpendicular ao plano do disco. A rotação do disco induz uma fem em movimento nele.
Considere um pequeno segmento do disco com um vetor de velocidade tangencial a ele. A força magnética neste segmento é radialmente para fora. Isso acumula cargas positivas livres em direção à borda e cargas negativas livres em direção ao centro, resultando em fem.
Integrando a equação de fem dentro dos limites do comprimento do segmento e substituindo a magnitude do vetor de velocidade obtém-se a magnitude da fem em movimento.
Este disco pode ser conectado ao circuito por meio de duas escovas estacionárias, que conduzem a corrente através do circuito fechado.
De acordo com a lei de Lenz, a corrente induzida se opõe à velocidade angular constante do disco. Portanto, o trabalho deve ser feito para manter o disco girando em velocidade angular constante.

<ol>
	<li>Young, H.D. e Freedman, R.A. (2012). Física Universitária com Física Moderna. São Francisco, CA: Pearson. Seção 29.4, páginas 971.</li>
</ol>

dínamo de disco de faraday

Um gerador de disco de Faraday é um gerador de corrente contínua, produzindo uma força eletromotriz (f.e.m.) constante no tempo. Ele consiste em um disco condutor que gira com uma velocidade angular constante em um campo magnético, que é perpendicular ao plano do disco. A rotação do disco causa uma mudança no fluxo magnético, que induz uma f.e.m., fazendo surgir cargas opostas na borda e no centro do disco. A polaridade da f.e.m. induzida pode ser determinada pela direção do campo magnético e pela direção da rotação do disco. Se o disco rotativo for conectado a um circuito externo usando escovas, então uma corrente induzida flui.

De acordo com a lei de Lenz, a f.e.m. induzida sempre se opõe à causa que a produz. Para o gerador de disco de Faraday, a f.e.m. induzida se opõe à rotação do disco. Portanto, energia externa deve ser fornecida para manter o disco girando com uma velocidade angular constante.

A f.e.m. induzida em tal gerador pode variar de alguns milivolts a alguns volts. A magnitude da f.e.m. induzida pode ser ampliada ainda mais conectando vários geradores em série ou aumentando a intensidade do campo magnético, o raio do disco ou a velocidade angular do disco.

Dínamo de Disco de Faraday

Um dínamo de disco de Faraday é um gerador DC, produzindo uma fem que é constante no tempo. Consiste em um disco condutor que gira com um ângulo constante ...

Education

JoVE Core

Physics

Física

Unit 1

Unidade 1

Electromagnetic Induction

Indução Eletromagnética

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

faraday disk dynamo and dc output

A Faraday disk dynamo is a DC generator that produces an emf constant in time. It uses a conducting disk that spins at constant angular velocity in a magnetic field. The magnetic field is perpendicular to the plane of the disk.

As the disk rotates, the magnetic flux changes and an emf is induced. This causes opposite charges to build up at the rim and at the center of the disk. The direction of the induced emf depends on the direction of the magnetic field and the direction of rotation.

If brushes connect the rotating disk to an external circuit, an induced current flows. Lenz’s law explains that the induced emf opposes the cause that creates it. In this case, the emf opposes the rotation of the disk, so outside power is needed to keep the disk moving at a constant angular velocity.

The induced emf in a Faraday disk dynamo can range from a few millivolts to a few volts. Its size can be increased by connecting multiple generators in series. It can also be raised by using a stronger magnetic field, a larger disk radius, or a faster disk rotation.

Faraday Disk Dynamo and DC Output

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faraday disk dynamo

A Faraday disk dynamo is a DC generator that produces an emf constant in time. It uses a conducting disk that spins at constant angular velocity in a magnetic field. The magnetic field is perpendicular to the plane of the disk. As the disk rotates, the magnetic flux changes and an emf is induced. This causes opposite charges to build up at the rim and at the center of the disk. The direction of the induced emf depends on the direction of the magnetic field and the direction of rotation. If...

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key terms and concepts

Learn how a Faraday disk dynamo makes steady DC output, builds charge on the disk, and uses Lenz’s law to resist rotation.

Faraday Disk Dynamo and DC Output | JoVE K12

physics

JoVE Core - Fisica apresenta a teoria e a aplicação de tópicos fundamentais da física, incluindo cinemática, dinâmica, mecânica dos fluidos, estática, ondas e acústica, com vídeos animados concisos e de fácil compreensão. Além disso, os vídeos de cientistas em ação demonstram a aplicação de conceitos relacionados em experimentos de pesquisa clássica e original realizados nos laboratórios de todo o mundo hoje em dia.

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Faraday Disk Dynamo and DC Output

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