Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [magnet]

97 questions
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Does Shielding "Electrically" shield "Magnetically" too?

I know it sounds like a newbie question but I can't wrap my mind around it. An electromagnetic field is electric + magnetic field. So this means that when shielding an equipment offensively, for example from avoiding causing interference with other…
user138887
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Construction for a homogeneous field using permanent magnets

Please let me describe what I am trying to achieve and I will pose my question in the end. I am trying to design a small chamber which can have a uniform magnetic field inside. I want to see if a design using permanent block magnets is feasible in…
tony31
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Are lithium ion batteries damaged by strong magnets?

I'm wondering if it is okay to put a lithium ion battery directly next to a strong permanent magnet. Would this affect the functioning of the battery? Can it lead to early failure? In the worst case, can it lead to an internal short circuit? In…
Alex I
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How an AC electric magnet works?

I want to know how an AC electric magnet works since the polarity of an AC current changing 100 times in each second (for 50Hz mains supply) so its magnet polarity(N & S) also will changed 100 times in each second. But i see AC solenoid always moved…
M.A.K
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Maintaining constant magnetic field strength with temperature

We use SmCo magnets to create a field strength of around 300mT. We choose this material, rather than NdFeB because the former has a much smaller change in field with temperature. For SmCo it is (apparently) around 0.03%/degC or roughly 1 part in…
Dirk Bruere
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Using Neodymium Magnets as wire connectors?

A new project I'm working has to be highly modular. All the electronics will be hidden in a case, so I was wondering if there's any way to use magnets and pass current through them for the project? It's well known that neodymium magnets could lose…
user33335
3
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1 answer

Why does a Hall sensor use a solid magnet?

I have disassembled two motor circuits that use a Hall sensor. One is a cooling fan blower and the other is a 230 VAC motor. The blower has a brushless motor and has its Hall sensor on the stator board with the coils. The rotor is a solid magnet…
metsik
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How to add a magnet to a coil's center without disturbing coil's charging effect?

I have a very nice wireless charger which can charge my smartwatch. Smartwatch itself contains a neodymium magnet on its back (and there are chargers which also contain another neodymium magnet to align the charger and chargee). This is how it looks…
Daniel
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Would a magnet interfere with NFC devices in this scenario?

I am thinking about manufacturing an interactive chessboard as a personal project. The circular pieces (resembling more or less poker chips in shape) would contain NFC tags, so it is possible for the devices hidden inside the board to collect…
francofeliardo
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Can strong magnets cause permanent damage to RFID tags?

I have an RFID-enabled ID card for work that is used for building access. While I can use a lanyard, cord-reel, etc. to carry the card and still have convenient access to it, I'd like to simply put it between my phone and its case. (I have…
FreeMan
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How to drive a magnet with a coil from an amplifier (to test acoustic guitar resonant frequencies)?

I wish to attach a rare earth magnet to pieces of wood and to acoustic guitars and drive the magnet with a signal generator through an amplifier to a coil. In essence, turning the wood into a loudspeaker. The purpose is to find the resonant…
D. Payne
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Impact of permanent magnet on component storage

This may sound like a silly question, but it got me thinking. Apart from my lab at work, I have an electronic workbench at home. Most of my components are stored in small, plastic cylindrical jars (imagine the ones used for storing medical pills,…
user68591
2
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1 answer

Problems of optimal commutation depending on number of pole

I am trying to design a three phase 4 pole motor, control with six-step. My problem appears when I draw the commutation to try to see how everything work. First, with a basic three phase 2 pole, there is no problemand the switching sequence seems…
Cyril
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How to apply Ampere's law with the integration path crossing a permanent magnet?

I read several books on permanent magnet synchronous machines (PMSM), and they tend to describe the relationship between H and B as \$B_{mag}=\mu_0\mu_{r,mag}H_{mag}+B_{rem}\$. Then when they apply Ampere's law \$\nabla \times H=J\$ with the…
8cold8hot
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What are these magnetic connectors called?

For a project, I am looking for a specific kind of magnetic connector. You can often find those on Apple products. It usually looks something like this: AliExpress Magnetic Connector The little pins are spring loaded I guess. The search for…
Maik
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