Questions tagged [magnet]
The magnet tag has no usage guidance.
110 questions
0
votes
1
answer
52
views
Confused, the AS5047P sensor allows for perpendicular positioning? So the edge of a diametric ring magnet will work?
I have a rod that is suspended by two bearings.
For the rotation to be measured I'd like to add a diametric ring magnet to the rod and have the sensor read the outer edge of that ring.
Will the AS5047 ...
- 15
4
votes
1
answer
326
views
Is it possible to smooth out a power signal from a magnet being dropped through a coil?
I am wanting to try some experiments to see how much power can be generated using various magnets and coils, but my understanding is the voltage is positive as the magnet approaches the coil and ...
- 43
1
vote
1
answer
79
views
Core memory output line question
How is a bit read from the core memory pictured below? I understand current through 1 and 1 vs 0 and 0 will change the torus magnets field setting a bit. I’m confused how this field is read back using ...
- 129
0
votes
1
answer
72
views
What is the max voltage I can apply to an electromagnet? [closed]
I have a small Amazon Electromagnet 4 ohms of resistance and wound with 110 feet of 28 AWG lacquered wire. What is the maximum sustained voltage I can put through it?
- 21
3
votes
3
answers
251
views
Deflection of current in a metal plate conductor
If I have a metal plate (square in shape) and an electric current moves from one side to the other. I understand that most of the current will take the path of least resistance but all paths will be ...
- 31
2
votes
1
answer
72
views
Can a coil reversibly modify the field of a permanent magnet?
If I have (say) a rod shaped neodymium magnet and wrap it with a coil, can I use the current in the coil to add to or subtract from the permanent magnet's field in a reversible manner?
Also, would the ...
- 14.3k
0
votes
1
answer
49
views
If I have two magnets repelling each other, will they always form a peak in the middle?
If I have two identical magnets, aligned so they repel each other a distance of X apart and at a height of Z I have Hall effect sensor, the peak of the magnetic field sensed will be at the distance X/...
0
votes
1
answer
51
views
Where does the electricity in electromagnets come from if permanent magnets from generators decrease their magnetic strength?
The question has been puzzling me for some time, I presume electrical power starts from generators, the heat produced by them(generators) cause their magnets to weaken and electromagnets have to be ...
- 151
0
votes
2
answers
136
views
Re-Magnetizing A Magna-Tip Screwdriver Handle
See what I added to the bottom of this question
Sorry for the high school level question. I would rather not spend my time experimenting. I have a quality gunsmith screwdriver set. The set contains ...
- 45
-1
votes
1
answer
83
views
Would a electromagnet be used to detect the presence of a permanent magnet?
I was wondering if there is any way I could use an electromagnet to detect the presence of a permanent magnet.
I am specifically thinking of using a planar type small coil. Maybe use a core or ...
- 31
0
votes
0
answers
111
views
Why is there no torque in electric motors when the Iq current is zero and Id current is not zero?
Random vector position of stator current ( Id + Iq = Is ):
Now I draw the stator current/flux vector as shown below where “Iq = 0” and “Id ≠ 0”:
From lecture I’ve learned that the south pole of the ...
- 101
1
vote
2
answers
246
views
Electromagnet design and powering it up? (Fault prevention of DC supply for a small coiled Electromagnet)
I want to create an array of multiple electromagnet which I will be controlling using a microcontroller.
I will have around 100 such magnets lined in a squared grid 10x10. Only three or five at a time ...
- 15
1
vote
3
answers
113
views
Is there a latching switch that will activate by motion?
I am working on a mini flashlight project. I would like to avoid holes in the enclosure to ensure waterproof-ness so using a standard slide switch is not an option for me.
I want to use a version of ...
- 119
0
votes
1
answer
39
views
Why is there a potential difference between VCC and Output pins of A3144 hall sensor?
When we bring a magnet near the A3144 sensor the PD between output and GND goes to zero but how come does the PD between output and VCC becomes equal to the PD of VCC and GND. Also when the magnet ...
3
votes
1
answer
514
views
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 ...
- 191
0
votes
0
answers
64
views
Making an automated chessboard [duplicate]
I want to create an automated chessboard. At the moment, I'm making the project and deciding what technology to use to detect which piece is at what position and how to move them. I'm not so skilled ...
- 43
0
votes
0
answers
221
views
How to test if a motor's magnets are demagnetized?
I have a motor in front of me which I'm fixing because a magnet came unglued. I was given it by someone else so it's unclear why the magnet glue failed. It could have been from heat, speed, or just a ...
- 786
0
votes
0
answers
88
views
Calculating optimum shape of an air core solenoid magnet pair with given number of turns
Consider a cylindrical \$N52\$ magnet with mass \$m_0\$ travelling in horizontal x-axis with initial velocity \$v_0\$ in \$-x\$ to \$+x\$ direction. It passes through an copper air core solenoid on ...
- 101
0
votes
0
answers
83
views
Reed Switch Selection - Quality Control
I have a piece of hardware which uses reed switches and neodymium magnets. When I attempt to produce this hardware in batches I find that some reed switches that I have are more sensitive than others ...
-1
votes
1
answer
647
views
How to extract electricity from a permanent magnet generator (PMG) to charge a 48V battery bank?
Here's the setup I'm attempting;
Small DC motor -> Turns my generator -> Outputs 0-250V DC -> ((Charges Batteries)) -> 48V Battery Bank -> Inverter -> Load
I have a homemade ...
Paul Evans
4
votes
2
answers
200
views
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 (...
- 14.3k
1
vote
2
answers
322
views
Can a weak external magnetic field damage a magnetron?
I have a 40-year old microwave oven. I temporarily attached a magnetic flashlight to the side of it. Its 5/8"-diameter magnet is likely a neodymium magnet, strong enough to secure the 10-ounce ...
- 305
3
votes
1
answer
574
views
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 ...
- 1,043
0
votes
1
answer
78
views
Why doesn't a guitar pickup's top and bottom cancel itself out? [closed]
A guitar pickup is a coil of wire with some magnets in the middle. The magnets magnetize the steel guitar strings. When those strings a strummed, they vibrate, and since they're magnets they induce a ...
- 109
0
votes
0
answers
74
views
Multiple LEDs with reed switches for testing magnet placement
I'm adding MIDI to an old electric organ (saving the existing internals for dual operation). I will be using reed switches and magnets at every key for action.
For testing magnet+reed positions I ...
- 11
2
votes
1
answer
244
views
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 ...
- 21
0
votes
1
answer
318
views
NFC and magnet interference in a concrete piece
Do you know if both NFC and a magnet would work correctly in this scenario?
I´m designing small pieces of concrete (imagine chess pieces) with three layers: magnet inside, NFC tag in the middle, and ...
- 11
1
vote
3
answers
224
views
How to trigger an 8 channel relay module with an air coil and moving magnet
I just bought this 8 channel relay module on Aliexpress, and I'd like to try to trigger it using an air coil and a moving magnet, but I'm unsure how to connect the coil to the trigger and collect the ...
- 119
-1
votes
1
answer
81
views
Does DC become AC through alternating permanent magnets?
As the title suggests.
Does direct current running through a circuit become alternating current if it goes through a linear line of alternating magnetic fields of permanent magnets, such as that of a ...
- 15
1
vote
1
answer
89
views
Why don't Li-pol accumulators change the polarity of an electromagnet?
I made a simple electromagnet with a screw and a wire.
When I supply power to it via 1 AA battery (1.5v) and change + and - contacts it acts differently with other magnets (attracts and repels), but ...
- 11
0
votes
1
answer
66
views
Baking an MC on a hotplate with magnetic stir
I recently got a batch of MCs (ESP32s) datasheet that were not in a desiccated and sealed bag. Because they are humidity sensitive devices and I am reflow soldering I needed to bake them to ensure ...
- 1,293
0
votes
1
answer
108
views
Is there a way to know which magnet pole is facing the circuit?
I am not that much into magnetism, but I am facing the problem of defining the pole of the closest outer magnet it faces the circuit with. The magnet is completely out of control and might as well ...
- 103
1
vote
2
answers
1k
views
Winding an electromagnet ring coil to get radial magnetic field
How can I wrap an electromagnet ring coil radially where the north pole is in the center and the south pole is at the outer ring? Is this possible to wrap?
Example:
I know I can wrap a simple coil ...
- 205
0
votes
1
answer
2k
views
Where to get the core for an electromagnet?
I understand that using a soft iron core or a ferrite core for an electromagnet increases the strength compared to an air-core. I'm going to be using DC current and want the core to be 5-8mm in ...
1
vote
1
answer
84
views
Question about storing magnetic parts (DC motors and speakers)
I always have a problem with storing magnetic parts, namely DC motors and speakers, because I am afraid if I let them attach together their magnets could interact and weaken/damage each other.
So I ...
- 320
0
votes
0
answers
106
views
tip3055/2N2222 coil steering
i want to switch an electromagnet with a 2N2222 & TIP3055
switching should be triggered by a coil passing a magnet as optcal would be to slow
can anybody assist or give us some advice. we don't ...
0
votes
3
answers
2k
views
Why are Halbach Arrays useful in PM motors?
I understand how Halbach arrays strengthen the magnetic field on one side of the array. I also know that, in a permanent magnet (PM) motor, there is already a limit on the air gap flux you can design ...
0
votes
2
answers
168
views
How to prevent external magnet rotate a motor
A small dc motor working and moving a disc. When device/motor is power off, a hacker with a strong magnet came and rotate the motor; without touching the motor, just moving the magnet near the motor ...
- 1
2
votes
0
answers
69
views
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 ...
- 175
0
votes
0
answers
26
views
BlueRay disc reader failed to disengage, how to fix
I got a BlueRay disk player which is failing to a very stupid mechanical defect. The spin head below this cover is magnetized and when the drive is closed it will raise and slot in the disc in the ...
0
votes
4
answers
18k
views
Why can't we use magnets to create energy like this?
Won't it rotate continuously?
Why can't this happen? Energy cannot be created, right?
Then will the magnets degrade over time and stop being magnets?
But they don't have their own energy also.
Then ...
- 189
0
votes
0
answers
93
views
Is there a way to make a edge to edge connection only using external magnets and gold fingers?
This question might sound pretty stupid, but I have been searching for solutions for a few days, so all of your new ideas are highly approsciated.
I am on a hunt for a solution for modularly ...
3
votes
2
answers
3k
views
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 ...
1
vote
0
answers
76
views
Derivation of magnetising force on the axis of a short solenoid
Reference I will refer to is Textbook of Electrical Technology by Theraja, page 268
(iv) Magnetising Force on the Axis of a Short Solenoid
The derivation is already there. I just don't understand the ...
- 469
0
votes
1
answer
102
views
Can a "mini" electromagnet propel a magnet 20 cm or so in the air
I have an idea to DIY a little thing that would require to throw a piece about 20 cm into the air (straight up).
My idea is the following: To have a mini electromagnet (such as this one ) and to have ...
- 109
10
votes
4
answers
1k
views
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 ...
- 103
2
votes
1
answer
981
views
What are these magnetic connectors called? [closed]
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 ...
- 65
0
votes
1
answer
87
views
Is there a chip capable (perhaps with a loop antenna) of sensing a 400-500 Gauss magnet at a distance of several inches?
Is anyone aware of a chip that is capable of detecting the approach (within several inches) of a fairly strong Neodymium magnet (~4000 Gauss):
https://www.digikey.com/product-detail/en/radial-magnet-...
- 113
0
votes
1
answer
199
views
How do I know that enamelled wire is actually conducting the current?
I am trying to make an electromagnet so I bought magnet wire to wrap around an iron core. I am pretty sure that there is a current running through the copper wire because I attached an alligator clip ...
0
votes
1
answer
120
views
Off-the-shelf electromagnet with deterministic pole
I looking to buy an electromagnet (12v) and there are a lot of them out there on amazon and ebay in all kinds of size and shapes -some are round, some are rectangle, etc. However, in my application, ...
- 157