Talk:Galvanometer

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It seems to me that Tangent galvanometer refers to the same instrument described here, using a more precise word for the basic instrument, but I'm no physicist. Should the two be merged? William Avery 12:57, 29 August 2005 (UTC)

A picture in the Tangent galvanometer would help a lot in understanding exactly what that gadget is, but based on the description in that article, it sounds like that's a different device than is being described here. Which leads to the real problem with this article:

The device described in this article is another form of galvanometer more-properly known as a D'Arsonval (sp?) meter. D'Arsonval meters have a fixed magnet and moving coil that is spring-loaded so as to return to its "zero" position. Energizingthe moving coil creates a magnetic force that rotates the coil away from the spring-established zero position.

By comparison, it sounds like a tangent galvanometer has a fixed coil and may depend on the earth's magnetic field as the "return" mechanism (as compared to the spring in the D'Arsonval movement).

This article should probably contain both devices, and make clear the distinction between the two. And there are still other ways of building meter movements, including spring-returned fixed-coil movements, electromagnetic-returned movements, thermal movements, etc.

Atlant 13:09, 30 August 2005 (UTC)

I see what you mean. 'The magnetic needle is free to rotate in the horizontal plane', so we are perturbing a compass. It's odd that Tangent galvanometer isn't linked to this article at all, and there's no link to the 'Tangent law' it mentions, either. (I have some vague recollection of rules involving fingers and thumbs at right angles to each other, like radii and tangents.) By the way, I wonder if I'd be right in thinking that those pretty equations would apply to all galvanometers containing coils, or are they just applicable to Tangent galvanometers?

William Avery 20:27, 30 August 2005 (UTC)

Answering my own question, those equations are about a compass needle in the earth's magnetic field, and won't apply to the D'Arsonval gavlvanometer. William Avery 20:45, 30 August 2005 (UTC)

[edit] Removed See Also section

... because most of what was there is already wikilinked in the article itself. And I don't see why a galvanometer article should have a see also about electrical quackery? I did leave the interwikis that an anon editor deleted. --Janke | Talk 18:44, 24 October 2005 (UTC)

[edit] A Link Is Not Required At This Time

I just came across this article about Galvanometers, and am surprised to see that the discussion still remains open. Someone previously wondered as to whether "those pretty equations would apply to all galvanometers containing coils, or are they just applicable to Tangent galvanometers?" The answer is that it's relative. If the equations contain the value B_h, then only an instrument which is effected by the magnetic field of the earth would require their usage. And yes, all things are effected by the earth's magnetic field, and gravity, but the question has to do with whether that effect is negligible in relationship to the usage.

Someone else referred to the Tangent Galvanometer as being "electrical quackery". Now there's not a lot of detail concerning the TG, but that does not make it fraudulent. My initial interpretation is that the coil forms an electro-magnet, and by its vertical rotation and proximity to the compass, while perpendicular to the horizontal plane, suggests that it might have some basis in scientific fact. If you could use an opposing magnetic field to cancel or divert the position of a compass' needle, you might be able to calculate for the strength of the magnetic field of the earth at that specific longitude and latitude by identifying Theta and the Current used by the coil. Whether the wirewound coil actually needs a non-magnetic core, or air core might be irrelevant to the equations. However, I have neither tried to build one, or have any intention or time to do so.

With that said, it seems to me that the best solution is to not link the two articles together at this particular point in time. There is no provided explanation as to why one might need to use a Tangent Galvanometer, outside of a Physics Lab experiment, and no history which makes reference to its creator. If there is no history and no modern purpose, or even an indication to a modern derivative of the device, it should only be considered valid as a possible, and perhaps plausible experiment in understanding the earth's magnetic field. All of this is to say that there should be no reason to continue with this discussion at this time, and the link should not be included, provided that if more information is later added to the Tangent Galvonmeter which merits a re-opening of the discussion, one should comply. --Theaudiodog 23:07, 10 May 2007 (UTC)

[edit] What is the Unit?

we are doing a science project for 9th grade and our teacher showed us a galvanometer. we obvsered that there were no units on the thing and that is our homework for tonight. any help? —The preceding unsigned comment was added by 216.54.156.245 (talk) 00:30, 9 January 2007 (UTC).