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Faraday's disc
Posted: 20 May 2013, 09:18
by 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
Re: Faraday's disc
Posted: 20 May 2013, 11:17
by smiley
Dunna but you can buy Faraday's torches from Jaycar or perhaps Dick Smith. Same principal, different housing.
Re: Faraday's disc
Posted: 21 May 2013, 11:04
by Graham Kemp
lada wrote: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.
Re: Faraday's disc
Posted: 21 May 2013, 11:41
by rae
We have a Wimshurst generator. Is it a similar thing??
Re: Faraday's disc
Posted: 21 May 2013, 13:37
by Graham Kemp
rae wrote: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.