Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [field]

80 questions
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Electrical Machines based on Electric Fields

Our teacher asked us this question during the lecture for Power Electromagnetics. We know that Electric Fields and Magnetic Fields are easily transformable into one another. And they are used greatly in various systems. He asked us why is it that…
Digvijay Gusain
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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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How can two identical charges affect a point when their fields lines never even touch?

If two identical charges were to be put beside each other, their field lines will not cross but rather go to infinity. In this case, if you put a point on any part of the two fields the other field can never affect it because its field line can…
An aspiring Scientist
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Sewing machine motor repair

I'm a sewing machine mechanic, trying to increase my electric motor knowledge. I have a Bernina 830 sewing motor where the carbon brushes ran down and the wire damaged the commutator and ran a groove in it. The motor was smoking. I took it apart, I…
Billie
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How does current flow inside a grounded coax shield?

I have been trying to reconcile the fact that current flows on the inside of a coax shield with the common practice of grounding the shield. These ideas seem contradictory at the moment. For a 2-wire transmission line it seems intuitive that both…
Ian_B
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Detecting atmospheric voltages on high altitude balloon

Our High school is launching a high-altitude balloon payload and the experiment we want to perform is the detection of atmospheric voltages. My friend and I were amazed when we saw this video where someone powered a small electrostatic motor with an…
skyler
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Why is it not standard practice to integrate the output of an antenna?

This is a follow up question from my question answered here: Why does a loop antenna not measure the differential magnetic field? Essentially I just found out today that we are actually measuring the derivative of the time varying electric field…
Christian
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What causes the electric field to change over series resistors?

So for example if we have a a wider and a narrower wire of the same length in series, since v1A1=v2A2, in the narrower wire the charges will move with a greater velocity. Since v is proportional to the electric field, this means that the electric…
Kakukk777
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Detrimental impact of magnetic field on PCB and battery?

We are developing a small consumer electronics product consisting of a small 4-layer PCB along with a few PDM microphones and BLE chip/ an antenna, as well as a LiPo battery. We are locating a small but pretty strong magnet next to these components…
T. Chains
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How does a capacitor resist changes in voltage?

I was reading about how capacitors work and two sentences confused me: "A capacitor’s ability to store energy as a function of voltage (potential difference between the two leads) results in a tendency to try to maintain voltage at a constant…
DigiNin Gravy
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What is the nature of the near field at a receiving antenna (excited by a far-away transmitter)?

Near and far field are usually explained for transmitting antennas, but since antennas are reciprocal, I would expect a receiving antenna to have a near-field phenomenon. 1) Does the impinging field (from a far-away transmitting antenna) cause the…
EEatWork
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Where can I find a good theoretical treatment of conductor shielding?

Suppose one has three current carrying cylinders lying on the same plane. Some of the electric field of the first conductor ends up on the second conductor, which creates capacitance \$C_{12}\$. But also some of the field lines of the first…
user120404
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Why does the Earth's electric field affect things so little?

Starting here: http://hypertextbook.com/facts/1998/TreshaEdwards.shtml "Over land the average electric field is about 120 V/m …. Assuming an exponential increase of the conductivity with altitude, it can be shown that the electric field decreases…
shieldfoss
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Does infinite magnetic permeability (e.g. for an ideal transformer) violate conservation of energy?

The ideal transformer is supposed to have infinite magnetic permeability. Creating infinite magnetic field lines from a finite applied field sounds like... a violation of conservation of energy or something? Is energy conserved? Source: What Is…
artist_and_not_EE_by_training
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Building a solid state regulator for a vintage 6 V dynamo

There was a great discussion back a few months ago on building a regulator for a dynamo. I have a similar challenge except the vintage motorcycle I'm restoring is a racing machine - neither lights not a battery (and no place for them). To the best…
clairefromperth
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