All Questions
Tagged with electromagnetism inductance
46
questions
2
votes
1
answer
7k
views
Transformers - Why more coils in second coil causes more voltage [duplicate]
I am learning about magnetic induction and transformers.
I have coil1 which uses AC to create an oscillating magnetic field.
I have ...
- 153
2
votes
1
answer
729
views
What happens if a current flows through a wire wrapped around a magnetised material?
A cylinder of radius $a$ has a uniform magnetisation along its axis, which results in zero bound volume current density and a bound surface current density $M\hat{\phi}$. A coil with $N$ turns and ...
- 4,607
2
votes
2
answers
5k
views
How to get the magnetic field strength in space near a solenoid
I am trying to find the magnetic field strength along the axis of a solenoid.
If I know the strength of the field at the center of the solenoid, and I know the distance from the center of the ...
- 1,340
2
votes
3
answers
644
views
How is EMF still induced in an incomplete/open circuit?
I understand that current can't flow through a coil if it is not complete, but surely this means that if a magnet is dropped through the coil, no EMF would be induced either, since work is done when a ...
- 31
2
votes
2
answers
1k
views
Magnetic flux inside solenoid
Suppose that I have a small coil that is moved at a steady rate into a solenoid. The solenoid already has a current passing through (basically, it is an electromagnet). The small coil starts beyond ...
- 21
2
votes
1
answer
989
views
Does a magnetized sphere contain energy
I believe this question is similar to "does a permanent magnet contain energy", which I understand to be no, but I just want to be sure. Say we have uniformly magnetized sphere with magnetization $M_0\...
- 612
1
vote
2
answers
1k
views
How can we derive the polarity of the induced voltage in an inductor?
As we know, the voltage-current relation of a two-terminal constant-inductance inductor is:
$v_L(t) = L \, \dfrac{\mathrm di_L(t)}{\mathrm dt} \tag 1$
I've managed to prove that equation without ...
- 344
1
vote
2
answers
137
views
Why does electrical impedance have as many parameters as it has?
The impedance of a circuit is written:
$$ Z(R,L,C,f) = R + j ( 2 \pi f L - \frac{1}{2 \pi f C} ). $$
What is the line of thinking that frequency, resistance, capacitance, and inductance are the only ...
- 161
1
vote
3
answers
19k
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Why in a solenoid, do the magnetic field lines resemble that of a bar magnet?
Each loop in the solenoid will have its own magnetic field wrapped around it. In that case it won't resemble the magnetic lines formed by a bar magnet...; but we see that it is the same. Why is that?
- 494
1
vote
1
answer
1k
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Why is the magnetic flux proportional to the current (Inductance)?
I'm trying to understand the reasoning behing this formula, or how to get there, if possible, using Maxwell's equations:
$$\Phi_i = L_i I_i + M_{ij} I_j$$
From the wikipedia page of inductance I got ...
- 121
1
vote
2
answers
820
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Contradiction using amperes law to calculate magnetic field $B$
I am trying to study the influence on the magnetic field B generated by a solenoid in two different cases
the solenoid is wound around an open iron core
the solenoid is wound around a closed iron ...
- 19
1
vote
1
answer
126
views
How to demonstrate the inductance of an inductor?
I have some troubles to demonstrate this formula. Actually my problem is about how the length of the coil is integrated in the formula... I could understand, that the electromotive force $V_L$ is ...
- 177
0
votes
1
answer
133
views
Phase difference
Is there a phase difference between the magnetic field and the current producing this field?
I have simulation results for three-phase transformer at different frequencies. The spectrum of the ...
- 1
0
votes
1
answer
3k
views
How to determine the polarities of inductor?
How to determine the polarities of inductor?
I know it is determined from Lenz law but most of the time i get a wrong answer,can anyone demonstrate how it is got, through an example?
- 399
0
votes
1
answer
471
views
Mutual inductance circuit analysis
given the following circuit, I need to find $ I_1(t) $ and $ I_2(t) $
(forgive my microsoft paint skills ;) )
I've come up with a solution, and I wish to check with you if it is current or, ...
- 113