Measuring change of magnetic field strengh over distance

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SUMMARY

This discussion centers on measuring the magnetic field strength of cylindrical neodymium magnets at a specified distance from their center. The user seeks to calculate the magnetic induction at a distance of 4 mm from a magnet with a known induction of 0.263 T. Participants recommend using a magnetometer for measurement and highlight the complexity of calculating magnetic fields, suggesting that numerical methods are typically required for accurate results. The user ultimately finds a solution through an online calculator, indicating that practical measurement tools are essential for this type of analysis.

PREREQUISITES
  • Understanding of magnetic induction and its units (Tesla)
  • Familiarity with cylindrical neodymium magnets and their properties
  • Basic knowledge of measurement tools such as magnetometers
  • Experience with numerical methods for magnetic field calculations
NEXT STEPS
  • Research the use of magnetometers for measuring magnetic fields
  • Explore online calculators for magnetic field strength calculations
  • Learn about numerical methods for modeling magnetic fields
  • Investigate the effects of neodymium magnets on electronic devices
USEFUL FOR

Engineers, physicists, and students involved in magnetic field research, particularly those working with neodymium magnets and magnetic induction measurements.

april7
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I have few cylindrical neodymium magnets of same diameter and different heights and different magnetic inductions in the geometric center of the magnetic pole surface. Knowing those values of magnetic induction, how can I measure what the induction is at a certain distance from that center?

For example height: 4 [mm] and induction: 0,263 [T]
What equation do I use to know what the induction is at distance of 4mm? I'm very much clueless about magnets and don't really know where to look.
 
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Get a Hall probe.

Trying to measure the field with another magbet is difficult, as each pole responds differently, and what you will see is the difference in the field between the two. Converting that to a field is non-trivial.
 
april7 said:
I have few cylindrical neodymium magnets of same diameter and different heights and different magnetic inductions in the geometric center of the magnetic pole surface. Knowing those values of magnetic induction, how can I measure what the induction is at a certain distance from that center?

For example height: 4 [mm] and induction: 0,263 [T]
What equation do I use to know what the induction is at distance of 4mm? I'm very much clueless about magnets and don't really know where to look.
Do you want to measure the magnetic field or calculate it? If you are "very much clueless about magnets" I suggest that you buy a magnetometer and measure it. There are apps for smartphones but I am not sure of their limitations for strong magnetic fields like yours. Also, bringing a neodymium magnet close to your smartphone might mess up its compass calibration or other "stuff".
 
Last edited:
kuruman said:
Do you want to measure the magnetic field or calculate it? If you are "very much clueless about magnets" I suggest that you buy a magnetometer and measure it. There are apps for smartphones but I am not sure of their limitations for strong magnetic fields like yours. Also, bringing a neodymium magnet close to your smartphone might mess up its compass calibration or other "stuff".
Yes, I haven't specified it but I need to calculate it
 
april7 said:
I need to calculate it
april7 said:
I'm very much clueless about magnets
Those two statements are mutually inconsistent.

What you want is very difficult and usually solved numerically. It is not for the clueless, I'm afraid,
 
Vanadium 50 said:
Those two statements are mutually inconsistent.

What you want is very difficult and usually solved numerically. It is not for the clueless, I'm afraid,
I'm doing my engineering thesis on superparamagnetic iron oxide nanoparticles (SPION) and I'm tasked with creating a model of magnetic pad we will use to stimulate particles with. I have to calculate which of few different neodymium magnets will give approximate value of 200 mT at distance of 4 mm. I want to know if I can calculate it and how I can do that without using programs.
 
Again, this is really hard. You don't even have adequately specified boundary conditions. As people have suggested, measure.
 
well I used chatgpt, asked same question and was directed to online calculator and softwares that can calculate it
I've got my answer now so I guess thread can be closed
 
Good luck.
 

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