Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [electromagnetism]

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 the site.

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My "nail and wire" electromagnet isn’t working

I’m trying to teach myself electrical engineering. I am trying to make an electromagnet using a 9V battery, alligator clips, and a steel bolt. Steps -> Wrap wire Connect power I have no magnetism. In fact my multimeter shows no current. The…
The Thinkrium
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How does a guitar body affect electromagnetic pickups?

If the pickups are just electromagnets detecting vibrations in metal strings, what effect does the guitar (size, shape, type of wood, solid body, hollow body) have on the pickups? Most argue that the pickups are similar to microphones. However,…
user4345
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How does a "coilgun" work?

I was wondering how that so-called "coilgun" works, I know what it does but I was wondering how it works under-the-hood and eventually how to make a basic one ? Also, how much energy would be required ?
Alexandre Cassagne
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Does heat affect the magnetic field of an electromagnet?

I know that heat destroys perm magnets, but how about electromagnetics? Does heat affect the strength of an electromagnetic field?
user3045
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What is the dielectric constant of a fly?

Kind of a random question, It has been a topic of debate in my lab. I guess the more specific question is: what materials is a fly's body made out of, and what are their dielectric properties?
CodeLikeSpaghetti
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Is there a magnetic field between capacitor plates while the capacitor is charging?

I've just began studying Maxwell's equations today and what really had my attention is Ampere's law, the second term in particular. $$\int\vec B \cdot d\vec l=μ_0I_{encl}+μ_0ε_0\frac{dΦ_E}{dt}$$ Does this mean that a changing electric field can…
John Katsantas
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Inductors & magnet - no vibration

I was trying to make a device which can vibrate - so I took inductor, some 220uH 22uH, put 12V pulsed current through it (~10Hz), and put neodymium magnet - I was expecting to feel 10Hz vibration of a magnet in my hands when holding it 1mm from the…
BarsMonster
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Why do electromagnets have itty bitty wires?

In videos like this one by electroboom, people make electromagnets with itty bitty wires. It seems the intuition is more turns, greater magnetic field. But I'm not so sure about that. Suppose we have some annealed copper wire at 20°C. (I used this…
Joseph Summerhays
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Best way to affect a compass in 2 meter distance

Visitors of two public exhibitions A and B are equipped with compasses. Exhibition A: I want to guide these visitors along a certain path throughout the exhibition by "overriding" the earth magnetic field so that they can follow there compasses…
InteractiveCube
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How does a "neon tester" work?

I have seen the different answer posted in internet. Many people are saying glow of neon light on tester is due to stray capacitor formed by our body and ground. I am ok with that until I found out tester also works on DC. So I get confused…
Beni Nepali
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How to build a constant magnetic field source for a "railgun"?

I'm trying to build a device similar to railgun. It will have two rails and a conductive movable bar in-between. At one side, I'll provide voltage source and a resistor. If I put it in a strong enough magnetic field, it will move. The idea is that…
AndrejaKo
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Voltage source connected to single inifinitely long wire

I have in my mind a thought experiment which I cannot figure out. Imagine a voltage source working on let's say 1 GHz. One end is connected to a ground, which is very small (we can abstractly assume it is just a point in space) and keeps constant…
Andrzej Dąbrowski
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EMF Induced Between Parallel Conductors

If two conductors (A and B), separated by a distance R, are parallel for a length ℓ and conductor B has an AC current flowing through it (I), what would be the equation to calculate the EMF (voltage) induced in conductor A between points 1 and 2.…
Chris Brown
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Driving an electromagnet with a 556 timer

I'm trying to drive an electromagnet with a 556 timer in a push pull configuration. The magnet has to change polarity rather quickly and sharply about 10 to 20khz. The voltage also has to be variable, between 3 to 15 volts the current draw is in the…
Chippyjames
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Can't get simple electromagnet to work

I'm trying to make a very simple electromagnet. I found a inductor, took it's copper wire and wrapped it around a nail. When I connect my bench power supply and crank it up to 20v, but I can't even pick up tiny metal pieces, it just seems like…
0x29a
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