Faraday's disc

[lada]

Does anyone know, what it is and who would stock it?
We have a very old one, which has 2 metal discs joined by a leather band( a bit like dynamo), with magnet attached to one of the discs.
Teacher wants a newer model
Thanks,
Lada

[smiley]

Dunna but you can buy Faraday's torches from Jaycar or perhaps Dick Smith. Same principal, different housing.

[Graham Kemp]

Does anyone know, what it is and who would stock it?
We have a very old one, which has 2 metal discs joined by a leather band( a bit like dynamo), with magnet attached to one of the discs.
Teacher wants a newer model
Thanks,
Lada

Yeap, it is a dynamo. The forerunner of dynamos rather. Invented by Michael Faraday.

The earliest design consisted of a single rotating conductive disk in a magenetic field, with one brush electrode near the axis and one near the rim. A later refinement used two disc joined by a metallic belt, with the discs in fields of opposed dirrections, so the electrode could be placed near the axis of both (thus reducing friction on the pickup brushes).

It's also called a Homopolar Generator.

[rae]

We have a Wimshurst generator. Is it a similar thing??

[Graham Kemp]

We have a Wimshurst generator. Is it a similar thing??

No, not quite. Different principle. No magnets involved.

It has two insulating discs, with metal strips inset into their surfaces, rotating in opposite directions (turned by a mechanical handle) passing crossed metal bars, with brushes, which are connected to two metal spheres forming a spark gap. The insets build up electric charge through electrostatic induction, until the accumulated charge is released in a spark.