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

K12 Standards

north-carolina-k-12-science-standard-course-of-study

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

Dynamo dyskowe Faradaya to generator prądu stałego, który działa na zasadzie indukcji.
Składa się z przewodzącego dysku obracającego się ze stałą prędkością kątową za pośrednictwem wału przewodzącego, który umieszczony jest w jednolitym polu magnetycznym prostopadłym do płaszczyzny dysku. Wirowanie dysku indukuje w nim ruchomy emf.
Rozważmy mały fragment dysku z wektorem prędkości stycznym do niego. Siła magnetyczna działająca na ten segment jest promieniowo skierowana na zewnątrz. To gromadzi wolne ładunki dodatnie w kierunku obręczy i wolne ładunki ujemne w kierunku środka, powodując emf.
Całkowanie równania emf w granicach długości segmentu i podstawienie wielkości wektora prędkości daje wielkość emf ruchu.
Dysk ten można podłączyć do obwodu za pomocą dwóch stacjonarnych szczotek, które przewodzą prąd przez zamkniętą pętlę.
Zgodnie z prawem Lenza, indukowany prąd przeciwstawia się stałej prędkości kątowej dysku. Należy więc wykonać pracę, aby dysk obracał się ze stałą prędkością kątową.

<ol>
	<li>Young, H.D i Freedman, R.A. (2012). Fizyka uniwersytecka z fizyką współczesną. San Francisco, Kalifornia: Pearson. Sekcja 29.4, strony 971.</li>
</ol>

dynamo z dyskiem faradaya

Dynmo z dyskiem Faradaya to generator prądu stałego wytwarzający siłę emf stałą w czasie. Składa się z przewodzącego dysku, który obraca się ze stałą prędkością kątową w polu magnetycznym, prostopadle do płaszczyzny dysku. Obrót dysku powoduje zmianę strumienia magnetycznego, co indukuje emf, powodując powstawanie przeciwnych ładunków na krawędzi i w środku dysku. Biegunowość indukowanego emf można określić na podstawie kierunku pola magnetycznego i kierunku obrotu dysku. Jeśli obracający się dysk zostanie podłączony do obwodu zewnętrznego za pomocą szczotek, wówczas popłynie prąd indukowany.

Zgodnie z prawem Lenza indukowany emf zawsze przeciwstawia się przyczynie, która go wytwarza. W przypadku dynama dyskowego Faradaya indukowany emf przeciwdziała obrotowi dysku. Dlatego należy zapewnić zewnętrzne zasilanie, aby dysk obracał się ze stałą prędkością kątową.

Siła indukowana w takim dynamo może wynosić od kilku miliwoltów do kilku woltów. Wielkość indukowanego emf można dodatkowo zwiększyć, łącząc szeregowo wiele generatorów lub zwiększając natężenie pola magnetycznego, promień dysku i prędkość kątową dysku.

Dynamo z dyskiem Faradaya

Dynamo dyskowe Faradaya to generator prądu stałego, wytwarzający stałe w czasie pole elektromagnetyczne. Składa się z przewodzącego dysku, który obraca się ze stałym kątowym ...

Education

JoVE Core

Physics

Fizyka

Unit 1

Jednostka 1

Electromagnetic Induction

Indukcja elektromagnetyczna

KEY TERMS AND CONCEPTS

Kluczowe terminy i pojęcia

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

induction

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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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induced electric fields: applications

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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

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Faraday Disk Dynamo and DC Output

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