Measuring magnetic field

eromlignod · 2005-07-20T16:44:03+00:00

Hi guys:I'm working on an application where I need a simple DC coil thatprovides a particular magnetic field strength. I have to experiment todetermine just how strong the field needs to be. So I have wound anarbitrary coil to experiment with. I will vary the voltage on it untilI experimentally achieve the necessary field in my application.Now when I know that this coil is producing the right field, how can Imeasure it? If I can get a measurment of the field intensity, I canwheel-and-deal mathematically with different voltages, wire gauges anddimensions of a coil so that I can design one to meet the fieldrequirement.Is there a simple way to do this without expensive equipment? Isuppose I could take apart my arbitrary test coil and calculate whatthe field must have been, working backwards, but is there a moredirect, emperical way? I want to be able to say, "My applicationrequires ______ teslas".DonMechanical Engineer

Jul 20, 2005 24 Replies

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eromlignod 21 years ago

This is interesting, John. Do you think that I might be able to use PCB-mount axial chokes (look like little green resistors) as my coils? Or will ferrite cores give me much pull? Maybe some other standard (cheap) inductor?

Don Kansas City

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Rich Grise 21 years ago

I just took a look at Digi-Key, and they have some reed relays for $1.19 in 100's. So I'm sure you can get coils cheap, now just look for some long E-cores, like Spehro suggested, and you might be done!

Good Luck! Rich

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John Popelish 21 years ago

I doubt it. You need a form that has the core extending out to the edge of the coil, so it is close to the string. Something like these might work:

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Especially if you cut he shrink tubing off. However supporting an axial version like these may be easier:

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Dan Major 21 years ago

"eromlignod" wrote in news:1121877843.165642.68820 @g14g2000cwa.googlegroups.com:

(snip)

How much influence does a magnetic field have on an (iron/steel) object? One way to measure the field strength would be to suspend an iron weight on a string. The deflection from vertical would give the force (do some simple vector analysis).

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