Important to inductors, transformers, generators, motors, magnetic fields, inductive heating, magnetic storage, permanent magnets

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Increasing the surface area of an electro magnet

I am trying to design an electro magnet with a large surface area at the end. The first design used a 1/4" rod wound with magnet wire resulting in about 10 ohms of resistance driven with 12 V. This ...
0
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1answer
57 views

How to design a magnetic vibrator?

I plan to create a magnetic vibrator to shake a small container. What I plan is to buy Two "Magnet Wire 14 AWG Gauge Enameled Copper 1.5lb 118ft 200C Magnetic Coil Winding" a custom made container ...
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0answers
39 views

Inductor stopping AC current [closed]

We know that a current opposes the change in the current and it stops the alternative current and allows direct current to flow. How does the conductor opposes the change in current and what is the ...
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3answers
70 views

How to detect non magnetic material?

I want to design a paintball counter. I have a metallic or plastic tube through which a paint ball passes. How can I detect that the ball passed? What kind of sensors do I need? I cannot see the ...
4
votes
1answer
696 views

Permanent magnets near wifi device

Background I have a small circuit that consists of a microcontroller operating on 14Mhz and a wifi module. This circuit is enclosed in a small plastic box. I am considering gluing a few magnets on ...
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3answers
70 views

Will running a DC motor below stall current damage it?

We have DC motors that power wheels on a car. Because of internal friction, the motors will not actually rotate until they are given 50%+ power. However, they do make some neat noises within this ...
2
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3answers
211 views

My DIY solenoid does not work

DESCRIPTION: Hi there, I don't know lot about electricity and I`m having problems with my first solenoid-prototype, I tried to build it watching you tube videos. I have attached the pictures of the ...
1
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1answer
69 views

When -EMF is induced can we keep current the same?

I'm confused at how Back EMF or (-V, -EMF) reduces current, and conserving the overall power. Let use the following simple example to help my understanding: A solenoid produces a magnetic field B, it ...
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1answer
89 views

How internal capacitor stud finders work?

I don't understand how can a non magnetic object like wood be detected using a stud finder For instance, stud finders find wood from dielectric constance, but I don't understand the princible. The ...
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2answers
81 views

Back EMF and opposing current of a super conductor?

A 5 meter long super conductor carries 100 Amps, and it passes through a 1 Tesla magnetic field at 0.010 seconds, Is EMF = - (BL) / (t)? And since the resistance of the super conducting wire is zero, ...
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2answers
45 views

RFID + permanent magnet

A project I'm exploring requires placing a permanent magnet in close proximity to an RFID tag (within a cm or so). Can an RFID tag be read when there's a permanent EM field so close to it?
0
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1answer
83 views

Powerful electromagnet?

Is it possible to produce over 1000 lb of magnetic force over a distance of 4 inches(0.101 meters), using an electromagnet? How difficult would it be? Explaining the general spec's of such an ...
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2answers
63 views

Resources for ferromagnetics

I am looking for experimental data on the experimental strength of magnetic fields inside ferromagnetic materials. Here is what I mean. If all of the magnetic moments of the molecules are aligned in ...
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2answers
101 views

Curie temperature

Does a ferrite core (or other material) have their magnetic characteristics changed when they reach curie temperature and goes below it (considering it does not suffer any mechanical damage from that) ...
2
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2answers
81 views

magnetics for ethernet PIC18f

I need to add ethernet connectivity to a PIC18f66j60. The datasheets tells about magnetics. But I know only very little about that. Do you know any surface-mount magnetics suitable for this use ? I ...
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3answers
88 views

Need to close or open a circuit (and keep it that way) with magnet

I need to build a circuit that closes when it detects the passing of a magnetic card. It should open again when the card passes again. So I need a simple magnetic reed (like this one). And some kind ...
4
votes
3answers
310 views

What is the difference between a transformer and a coupled inductor?

Transformers and coupled inductors seem very similar. Is there a difference in construction? Or only in use? This question asks something similar, but the answers don't address my question: Coupled ...
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2answers
127 views

What is the difference between the magnetic H field and the B field?

Wikipedia provides a mathematical explanation. Can I get the intuitive one? I'd like to, for example, understand a ferrite datasheet. These usually have graphs of H vs B, and the definition of ...
3
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2answers
75 views

Homebuilt magnetic tape head

I have seen a lot of projects that use a tape head, but there is very less information about how to build one yourself. Is this possible? I know that basically it is a metal core, with a coil around ...
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1answer
97 views

Magnetic Equivalent Circuit

Is this correct magnetic equivalent circuit for this electromagnet system ? simulate this circuit – Schematic created using CircuitLab And i am trying to solve it like this example, ...
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0answers
97 views

Simulating a magnetic field in Spice

I am trying to simulate a circuit that involves pickup coils in Spice. How would one simulate the magnetic fields that the pickup coils can sense? Additionally, how would one get a frequency response ...
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2answers
98 views

Electro-magnetism. What's it all about anyway? [closed]

Ok, so am new to electronics. I've been looking up various thing like basic theory, schematics, circuit components, logic gates, and the rest. So all of that (on an extremely basic level anyway), I ...
0
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1answer
74 views

Designing a purely reactive circuit with the following requirements

how would you design a purely reactive circuit with: Infinite impedance in f = 0 Hz and f = 800 Hz Zero impedance in f = 5000 Hz and 11000 Hz At 7000 Hz, has a reactance of 181.85 Ohms How to proceed ...
2
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1answer
231 views

Digital Compass: Can it be calibrated/shielded to prevent normal operation in the presence of ferromagnetic materials

I am currently working on a hobby project, for which I would need a reliable compass that should work in as wide a range of environments as possible (i.e.: In a field, in a car, on a train, possibly ...
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3answers
166 views

What mechanism happens inside an inductor from the point when potential difference is applied?

What happens when a potential difference is applied across an inductor? I am trying to get a picture of mechanism from start, just after potential difference is applied in detail? In resistor we can ...
4
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1answer
192 views

Magnetic field strength and bldc rotor

As a background to this project, I have taken an off the shelf bldc stator and incorporated it into a small pump, and then built my own rotor using discrete neodymium magnets. At first, everything ...
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2answers
153 views

What are the specifics of PoE ethernet magnetics

I have a PoE powered design, and it is currently equipped with magnetics not labelled as PoE, HX1188NL. There is also a transformer with a similar topology, HX2019NL. However, the only difference I ...
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1answer
153 views

Is it possible to create an external electric field using a toroid?

I would like to create a directional, "external" electric field. For example, a solenoid creates an "external" magnetic field in one direction(coming out of the ends of the solenoid). I would like to ...
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0answers
86 views

Ground plane and magnets

I am making a wheel encoder out of a Hall Effect sensor with magnets in a concentric circle on the wheel. The Hall effect sensor is on a 2-layer 9x5mm pcb. I usually fill in the layers by drawing a ...
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5answers
300 views

What is the best way to make a speaker louder

What are the pros/cons of adding more coils or getting a stronger magnet for a speaker? Are there other methods to make them louder keeping the power supplied to the speaker the same?
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2answers
898 views

Saturation current of my inductor not agreeing with formulas

I have wound my first inductor and I have verified the inductance with 2 methods. However, when I test its saturation current, its much lower than the formula gave me: \$B_{peak} = \frac{V\cdot ...
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1answer
206 views

How to detect a magnetic field going over a coil?

I have a coil with solid core, there is an small magnet that pass over it (like on the image) but not touching the coil (there is an small plastic between them, no more than 0.5mm thick). I need to ...
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2answers
91 views

Effect of magnets on LCD monitors? [closed]

Do speaker magnet's have any effect on the LCD monitor. because few month's ago one of mine went faulty dark patches produced on it which when pressed behaved like liquid i.e. when i pressed the the ...
6
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2answers
187 views

What are the physical mechanisms of core loss, and how can they be minimized?

Suppose you have an inductor in a boost converter. The core gets hot. Why? What are the physical mechanisms that cause core loss? Eddy currents? Magnetic domains flipping? Coupling to materials ...
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2answers
288 views

How do I determine safe distance from a choke to prevent accidental coupling?

In most of my power converter applications, I end up with a choke of some description, somewhere in a steel chassis. I have seen and heard tell of situations where the choke couples to the steel of ...
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4answers
293 views

How to track motion of a moving ovendoor

At work, we are measuring various parameters to test out a newly designed oven prototype. To make things more efficient, I am trying to create an electronic setup to automate the measurement, in ...
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1answer
92 views

Protective insulation for magnet installed in earth

My this question is a part of a question I earlier asked sensor to detect magnetism. So please don't refer it as non-engineering question. I had to install some neodymium magnets in the earth. Their ...
0
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1answer
154 views

How to implement a radial encoder with a diametrically magnetized magnet using a hall-effect sensor?

I want to implement a rotary encoder that doesn't use optical sensing or physical contacts. I found the following solution using a diametrically magnetized magnet on the shaft, and a dual axis hall ...
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3answers
94 views

Magnetic Field Transmission

I have heard from here that if you put 1 turn of wire around your house, you can hear music all around inside your house. It doesen't tell me very much on all of the components etc. to drive but I am ...
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1answer
144 views

Electromagnet duty cycle

I have a project where I would like to use an electromagnet to lift an item for a longer period of time. I was looking at a magnet like this one: ...
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1answer
160 views

How to Estimate Rotational Velocity of a Beakman's Motor?

What is the equation to determine the rotations per second of a Beakman's Motor (a.k.a. half-motor or single pole pulse motor, composed of a power source and a single coil with 1/2 exposed coil leads ...
2
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1answer
102 views

Electromagnet interference with motorcycle

I just got a sport bike which the frame is aluminum the engine is aluminum the swing arm as well. Basically this bike is made up of mainly aluminum and plastics with very little steel or any other ...
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0answers
266 views

How to route Gigabit Ethernet, remote PHY or remote RJ45 connector?

I need to design a 10/100/1000 BASE-T “backplane” board that contains multiple PHY outputs from Ethernet controller chips. On the board ,the LAN specifications are very strict in regard to how the ...
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1answer
449 views

Amperian loop to measure solenoid's magnetic field

My textbook proves the formula \$B =\mu_0In \$ for a solenoid by taking a rectangular Amperian loop as shown here: The problem I see with this though is that it only takes into account the ...
2
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2answers
220 views

Magnetic Encoders - Tips and Tricks

I am new to encoders in general and I am thinking about using a magnetic encoder in a personal project were I will need to make my own servo, and thus get an absolute position reading (instead of the ...
0
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1answer
417 views

magnetic field outside solenoid

It is written in our course book that the magnetic field outside a solenoid is negligible and almost zero. Why is it negligible? Is it negligible compared to the field inside solenoid or is it nearly ...
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1answer
56 views

Am I following the procedure to set the sensitivity in Try Mode for the A1362 Hall-Effect sensor correctly?

I am following Figure 5 pg. 18 of this data sheet: Vp(HIGH), Vp(MID), Vp(HIGH), followed by 0-255 Vp(MID) pulses that increase the sensitivity each time Vp(MID) is applied. However, when I bring ...
8
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1answer
419 views

Differences between a planar coil and coplanar waveguide to create a local 1D AC magnetic field

Coplanar waveguides (for example picture look here) are often used in research to create a local in-plane magnetic field. Now if compared to a planar microcoil like this, driven by a AC voltage in ...
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2answers
578 views

Sensing magnetic pulses from a rowing boat impeller

I'm a mechanical engineer at uni who has some basic experience in electronics and programming. I'm building a system for my rowing boat to help me with my training. This will give me feedback on a ...
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1answer
230 views

How to choose a reed switch and magnet?

I need to use a reed switch and a magnet on a shaft. When it get turned to a specific degree the magnet will trigger the reed switch. The shaft only turns one way and is turned by hand. The problem ...