The kind of magic without which all of this wouldn't be possible. This tag should be used for questions about the **physics** of the fields that charged particles create and how these fields interact. It should not be used for all questions involving electromagnetism, that would be everything on ...

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1answer
38 views

4x4 Switch Matrix Problem Please Help [on hold]

we are trying to built Electronic Locker Which is Controlling by a specific Combinational Password but we have a Problem with (4x4 Switch Matrix Numbering Order) In the Circuit Diagram the numbering ...
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0answers
35 views

Simple Electric Motor [on hold]

I want to make a really efficient but simple brushless motor by using a magnet, ferrite core, and coil. What are the formulas I would need to calculate the force/ power of the magnets and coils? ...
0
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1answer
30 views

Low weight split core transformer on 11kVA transmission line

I've seen transmission line energy harvester's that utilise a split core transformer. Here is an example. However, I fail to see how this is possible when a transformer cores which are small enough ...
0
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1answer
21 views

converting inductance to electromagnetic force

How might one determine the amount of electromagnetic force produced by an unshielded inductor? E.g. How much holding force does a 600uH unshielded inductor posses? Or alternatively in reverse: How ...
0
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1answer
64 views

Electromechancial locks used in a turnstile

I was looking to build a RFID operated turnstile similar to picture below. I will have RFID readers on both ends where the door would open from either end only if the RFID is authenticated on either ...
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0answers
26 views

How do I calculate magnetic flux density?

Calculate (for the kinked line conductor) the magnetic flux density (vector) at the place P. I know i should use formula: \$\vec{B}= \frac{\mu_0I}{4\pi\rho} \left[\sin(\alpha _2)-\sin(\alpha ...
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1answer
33 views

Effects on the exterior magnetic field from a field induced by a wire?

I have an experimental set-up where I place a conductive wire in a magnetic field created by an electromagnet like so: There is current flowing in a wire as well(aside from the electromagnet) ...
0
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0answers
39 views

Why Can Capicators Have All Their Charges Separated?

Conceptually, if a molecular structure separates all of its charges, like in the 2 plates of a capacitor, this should leave a uniformity of charge either holes or electrons with a large voltage ...
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2answers
75 views

Wireless energy scavenging from in-home wiring EM fields

I was wondering if it would be possible to power a little 3.3V microcontroller, by harvesting an electromagnetic field around an in-wall insulated 240V 50Hz AC power cable. Something like contactless ...
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1answer
19 views

\$2n\$ point charges on a circle at \$O\$, what's total electric field intensity \$\overline{E}\$ at \$\pm 1\mathrm{m}\$?

The problem reads is from a Schaum's Outlines of EMFT and reads: A total charge of \$1\mathrm{nC}\$ is equally distributed among \$2n\$ points which are placed equidistantly on a circle with ...
3
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1answer
46 views

accuracy of magnetic field sensors in electrical vehicles

For coordinate system alignment purposes, as demonstrated in the figure, I want to use the smartphone's virtual orientation sensor. However, the virtual sensor is using a combination of acceleration, ...
0
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1answer
88 views

Designing a generator

I am modeling the output voltage of an AC generator and I am using/I chose the following specifics: Number coil turns = 300. This is 1.02 mm gauge copper wire, so knowing the density of copper, I ...
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1answer
53 views

How to increase an electromagnet's magnetic field size

So i made this electromagnet out of a microwave oven transformer by taking out the secondary coil. It very strong but it can only attract the metals if i bring it really close. How do increase the ...
0
votes
1answer
32 views

Controlling an electromagnetic switch with Reed switches

I'm trying to power a 12v electromagnetic switch using NO reed switches. IE: when the 5 reed switches all have magnets near them then the elecromagnet switch unlocks something. However, I'm trying ...
1
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0answers
43 views

Calculate induced voltage in a wire due to mains wiring

I wish to calculate voltage induced in a short piece of wire of known length, due to mains household wiring carrying some current say 5 amps. My application is biomedical sensor wire and I can not use ...
0
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0answers
26 views

Eddy currents of a single thin wire

Given a copper wire length of 2m, and a diameter of 1mm moving in a strong magnetic field(1T+) at a high velocity(20m/s), is it reasonable to assume the Eddy currents = 0? Due to their small area, ...
0
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1answer
47 views

How does a moving magnetic field cause motion in the Al strip rotor?

Consider the following information: https://www.youtube.com/watch?v=7snjbmdYlDI How would you explain how the moving magnetic field causes motion in AL labeled rotor?
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votes
1answer
80 views

How can I describe mathematically what is happening in my home made LVDT variant?

I've built an LVDT (Linear Variable Differential Transformer) that is a little different than how it is conventionally done with 2 secondary coils positioned adjacent to a primary coil. My design is a ...
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votes
1answer
44 views

Produce current

Ok, so I was trying our an experiment to generate minute current. I got a battery operated gear motor which can produce current to light ant led bulb when rotated. I am trying to create an automation ...
-2
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1answer
105 views

DC generator without permanent magnets

I have heard that there are DC generators where resistance can be regulated by using electro-magnetic field. Where permanent magnets are substituted with electro-magnets. Are this kind of generator ...
-5
votes
1answer
46 views

Build 0.5 T solenoid with [closed]

I want to build 0.5T solenoid (Length 30 cm and diameter 0.5 cm). Can anyone provide me the formula taken into account the length, radius of the solenoid and Radius of wire, i.e. Outer radius after ...
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votes
2answers
85 views

Should I get EE or CS major? [closed]

I don't know whether this is the place to ask this. I'm sorry if this is the wrong place. I'm a first year university student in Electrical Engineering and Informatics School. In my second year, I ...
0
votes
2answers
53 views

Will this structure emit EM waves when excited by out-of-plane time varying magnetic field?

Say I create a structure from copper that looks like the figure shown below. It's an open circle whose ends terminate in protruding wires of length x. If I excite this with an out-of plane time ...
0
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2answers
91 views

Increasing efficiency of a kinetic energy battery charger

I want to use Faradays law to convert the kinetic energy from actions such as a jog/shake to produce electricity to ultimately charge a battery. Materials Neodynium Magnet 3/4 diameter (2) ...
0
votes
2answers
72 views

Ways to use electromagnets to pick up metal shavings at a distance

I work at a rotor machining plant and there is an issue for shutting a line down to clean up metal shavings, causes too much down time. I was thinking of using a strong electromagnet to have a "pick ...
0
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1answer
55 views

Propagation across a surface

How do stud sensors actually sense current, what would cause the effect to propagate across an 8x8 foot surface area and remain strong enough to be detected? I asked another group "what is ...
0
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1answer
43 views

Formula for electromagnet strength parallel, outside the coil

I am working on a electromagnet project to collect metal shavings off the floor after machining. I have a formula for the magnetic strength at a distance from the ends, but not parallel to the coil. ...
0
votes
2answers
35 views

Can we make a simple wireless device by mutual induction phenomenon

I want to make a simple wireless device (radio?) that consists of only two copper coils where changing magnetic flux in primary coil causes a current flow in the secondary. I tried, once, with LEDs ...
0
votes
1answer
79 views

Magnetic switch with no moving parts

Is there a magnetic switch (like a reed switch) but with no moving parts? I need a switch that can be turned on by a magnetic field but won't move around due to tremendous shock absorption.
0
votes
2answers
82 views

Reactive Power in Inductor and Capacitor

Suppose a RLC circuit with AC source. Why the net reactive power in the circuit is the difference of reactive power in the inductor and the reactive power in the capacitor ? As both of them store ...
0
votes
0answers
45 views

There is thermochromic pigment. Is there a magnetic variety of pigment?

I can mix thermochromic pigment with transparent epoxy resin into a brightly colored paste which changes colors when it detects a temperature threshold in the surface it is applied to. Is it ...
1
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3answers
118 views

Complex impedance of a transformer

I consider only an ideal transformer here (no leakage etc.). Let L1 and L2 be the induction coefficients of the primary and secondary resp., and M be the mutual induction coefficient. Assume that the ...
1
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3answers
126 views

Reactive Power in the circuit

Why is inductive reactive power considered positive while capacitive reactive power is considered negative in the circuit ? Both inductor and capacitor consume apparent power so I guess ...
0
votes
4answers
150 views

Make an electromagnet attract and repulse

I bought and electromagnet online hoping to make it attract and repulse metals changing the polarity of the voltage on it, but I ended up experiencing attraction all the time. Is there any way to ...
0
votes
1answer
66 views

What method do wireless routers use to break apart the received wave into different frequencies?

What method do wireless routers use to break apart the received wave into different frequencies ? Does it have anything to do with Fourier Transformations ?
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1answer
72 views

ionizing body with tesla coil?

I have made a tesla coil.Now I want to ionize my body with it so that I can give shock to people with my hands.Is it possible to shock someone with it?
0
votes
1answer
50 views

Welding Transformers?

I was thinking of making a carry handle for two microwave oven transformers in series, and also so that they can share a common ground without having to split the ground wire. I thought about bolting ...
-1
votes
1answer
64 views

What are the options for short range under six inches 3D multi point location tracking?

What methods exist to track the position of points relative to each other. Particularly what methods allow the determination of the distance between up to ten points at once. The distance ...
1
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0answers
34 views

Torque and Current Frequency Relationship in Lorentz force

Lorentz force equation shows us that current is proportional to the force. Is it safe to assume that the force generated by an AC current at 60Hz will always have the same frequency? In other words, ...
1
vote
3answers
82 views

Hall effect device for circa 1 tesla gaussmeter

I'm thinking about building an unsophisticated bench instrument for measuring magnetic field density, just to support my learning about electromagnetism and building magnetics for power electronics ...
2
votes
1answer
41 views

What is vector potential in magnetic field?

The vector potential in magnetic field (represented by A), what does that physically mean? I have serious problem in understanding it intuitively. $$\nabla^2\text{A} = -\mu_0 \text{j}$$ I read that ...
0
votes
1answer
45 views

Magnetic attraction/repulsion with motor/generator and similar systems?

With generators and motors, is there a form of magnetic attraction or repulsion between the conductive element(rotor/solenoid) and the magnet's magnetic fields? If so, what formula would be best to ...
1
vote
1answer
42 views

Interpretation of radiation resistance in receiving mode

Assume we have an antenna in receiving mode, connected to a matched load. The equivalent circuit is a voltage source in series with the antenna feedpoint impedance and the load impedance. As we know, ...
-6
votes
2answers
73 views

How electromagnetic waves works, how they are created and how thay transform to electric signal? [closed]

Few days I am trying to learn more about electromagnetic waves, induction, electromagnetic spectrum... And how it's connected. Here is what I understand now: There is a lot of electromagnetic waves ...
2
votes
2answers
63 views

Moving the magnetic field around a fixed conductor?

From this figure: And many others related to electromagnetic induction, the main component of motion would be the conductor perpendicular to a magnetic field. I know it's possible to have it the ...
0
votes
0answers
23 views

Change in induced EMF due to change in wire connection?

A copper slab moving inside a magnetic field: I can calculate the induced EMF(vBL) and given the resistance of the load, can calculate the current. However, I'm curious with how the ...
0
votes
1answer
298 views

smallest possible length of copper wire, where I can measure capacitance via multimeter

I am a new highschool physics instructor and I want to show to my students the basic concept inside capacitors and how they work. I plan on showing them 2 simple copper wires side by side , ...
0
votes
1answer
68 views

Calculating a compass angle?

I am getting data from compass( hmC5883L) and trying to detect angle. Well, i dont really care about offsets, i just want to check that if its flat on the table ...
0
votes
2answers
52 views

Magnetometer- there is no low current feature?

I have gone over all magnetometers available, most of them using I2C, and connected to some MCU, and i couldn't find even one with interrupt. That means the processor cant go to sleep, and always has ...
0
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0answers
53 views

Three Phase Permanent Magnet Rotor Generator Magnetization

I have a three phase permanent magnet rotor synchronous generator. The rotor was recently removed from the machine in order to repair the shaft. The motor when when run at the same speed does not ...