All Questions
Tagged with electromagnetism inductance
384
questions
58
votes
7
answers
21k
views
Cyclist's electrical tingling under power lines
It's been happening to me for years. I finally decided to ask users who are better with "practical physics" when I was told that my experience – that I am going to describe momentarily – prove that I ...
- 180k
21
votes
4
answers
41k
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Derivation of self-inductance of a long wire
Currently I am stuck, trying to derive the self-inductance of a long wire. According to literature it should be
$$L=\frac{\mu_r\mu_0l}{8\pi}$$
and in literature its derived by looking at the energy ...
- 1,573
19
votes
2
answers
999
views
Are there analogs to resistance, inductance, capacitance, and memristance connecting the weak force to electromagnetism?
A question was asked over at EE.SE recently which I tried to answer, but much of my answer was speculative. I'm hoping someone here can help my ignorance.
In electronics design, there are four ...
- 429
18
votes
3
answers
11k
views
Faraday's law - does the induced current's magnetic field affect the change in flux?
I've had this conceptual problem with Faraday's law and inductance for a while now.
Take the example of a simple current loop with increasing area in a constant field (as in this answer). So Faraday'...
- 533
11
votes
3
answers
9k
views
When mutual inductance is occurring between two coils, is self inductance always occurring in each individual coil?
When a coil connected to an AC generator creates an EMF in another nearby coil (mutual inductance), is self inductance simultaneously occurring in both coils?
- 545
10
votes
4
answers
4k
views
Where does the extra energy come from in an LC circuit?
In an LC circuit, or an LC tank, the capacitor discharges in one direction
through an inductor and then the inductor seems to carry energy in the form of a magnetic field , to charge the capacitor ...
- 607
10
votes
3
answers
3k
views
Does a thermal inductor exist?
There is an analogy between electric and thermal circuits.
A voltage difference is equivalent to a thermal difference.
$$\Delta V \equiv \Delta T$$
Electric charge $q$ is equivalent to heat $Q$.
...
- 281
10
votes
5
answers
10k
views
Magnetostatic energy density -- derivation without introducing inductance?
I was looking for a derivation of the expression for the energy density at any point in a static magnetic field. I do know that it is
$$u_B=\dfrac {1}{2 \mu_0}\left|\mathbf{B}\right|^2,$$
I was just ...
- 625
8
votes
1
answer
1k
views
Reluctance of torus shaped iron core with embedded wire loop
Imagine a circular wire loop (r = 50mm), the wire has an assumed diameter of zero, which is embedded in a torus shaped iron core with a circular cross-section of R = 10mm.
A current in that loop would ...
- 153
7
votes
1
answer
538
views
Is Back EMF produced in household wires?
Since we use AC for domestic purpose, shouldn't Back EMF (Counter-EMF) be produced in household wires? If yes, then the output voltage in the appliances will be less (that's what my stupid brain says! ...
- 93
6
votes
3
answers
2k
views
Confusion in understanding the behavior of inductor in RL circuit with DC source
When we have a DC voltage source with a switch in series with $RL$ and the switch is closed at $t=0$ then it is said that current is zero initially, but the voltage across inductor is same as that of ...
6
votes
3
answers
4k
views
Why do Capacitor Inductor circuits Oscillate instead of reaching equilibrium?
When the capacitor is fully charged there is a potential difference between its poles and that creates a current.
This current would create a magnetic field that is changing in the Inductor (because ...
- 411
6
votes
2
answers
1k
views
Why is all of the energy from a battery stored on an inductor but only 50% on a capacitor?
I am learning about inductors and capacitors and we derived the energy stored on a capacitor to be 50% of that delivered by the battery. We did this considering a circuit of a capacitor connected to a ...
- 3,997
6
votes
2
answers
7k
views
How to calculate required current and specifications for a "wet coil" to generate x Tesla of magnetic field?
A water management project requires a "wet coil" (coil will be submerged in aqueous media) designed to generate a steady-state electromagnetic field of adjustable magnetic magnetic flux density at the ...
- 163
5
votes
5
answers
2k
views
Where does the energy stored in inductor go on opening the switch?
Suppose we have a simple RL circuit. At $t=0$, I close the switch so that current starts flowing in the circuit. When the steady state is achieved, current $i=\frac{\epsilon}{R}$ would be flowing in ...
- 123
5
votes
4
answers
4k
views
Why do magnetic coils consist of many thin wires?
Magnetic coils are usually made of thin wire turned into spring shape:
Magnetic field which is generated by this solenoid is proportional to the number of turns N. ...
- 1,732
5
votes
2
answers
23k
views
Relationship between inductance and number of turns in a coil in loudspeaker
I am in the process of designing a loudspeaker and have a question regarding the number of turns in the multilayered solenoidal coil and the speaker impedance of $8\:\Omega$. I understand that the ...
- 51
5
votes
1
answer
532
views
Current through a solenoid: magnetic field gives a staircase graph
We were running current through a solenoid coil with an iron core, and measuring the resultant magnetic field strength. We expected a purely linear relation for the "current-field strength" ...
- 51
4
votes
2
answers
352
views
What does the metres squared represent in the dipole moment?
If I were to do an experiment measuring the magnetic field strength (in tesla) of an iron core solenoid magnet, how would I determine the value for the dipole moment in the formula displayed in https:/...
- 53
4
votes
4
answers
2k
views
What are the practical use of LC oscillations?
I understand how energy is transferred between the capacitor and the inductor in an LC circuit, but I am not sure what are the practical applications. Could someone please help?
- 1,481
4
votes
5
answers
49k
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What is the difference between electromagnet and solenoid?
What is the difference between electromagnet and solenoid? Both these terms seem as the same thing to me. The only difference that I can find seems to be that an electromagnet contains a soft iron ...
- 179
4
votes
2
answers
6k
views
Magnetic moment of an iron-core solenoid
I'm currently developing a Simulink model for the attitude control system (ACS) of an undergrad-developed CubeSat. The ACS uses magnetorquers for attitude actuation.
The magnetorquers are iron-nickel ...
- 93
4
votes
1
answer
299
views
Why can voltages be summed around a circuit if there is magnetic induction?
So there is this class I'm attending on Electronic Instrumentation which involves mostly circuit analysis. For example, RCL circuits, and circuits that also contain opamps, transistors, diodes, etc. ...
- 117
4
votes
2
answers
3k
views
Why does the current increase in an LC circuit while the capacitor is being discharged?
From the maths governing an LC circuit (eg. $E_B=\frac{LI^2}{2}$) we can deduce, that the current through the inductor will have a maximum value, when there's no energy stored in the capacitor, or ...
- 773
4
votes
1
answer
48k
views
Magnetic field due to a coil of N turns and a solenoid [duplicate]
I have learnt that the formula for calculating the magnetic field at the centre of a current-carrying coil of $N$ turns is:- $$ B = \frac {\mu N I}{2r}$$
(where $r=$ radius of the loop,
$I=$ current ...
- 197
4
votes
1
answer
63
views
Why In the following $RL$ circuit, the connection to $b$ must actually be made an instant before the connection to $a$ Is broken? [duplicate]
In Resnick halliday, student 10th edition page - 795. In the topic current decay in RL circuit, the following statement is used, the connection to b must actually be made an instant before the ...
- 43
4
votes
2
answers
537
views
What does 'Oppose a Change in Current' really mean from Lenz Law?
We all know what Lenz Law is, but I have a bit of trouble conceptualizing the phrase above. Does 'Oppose a Change in Current' means it will take more time for the current to increase to its maximum ...
user215726
4
votes
5
answers
2k
views
Isn't the inductor equation negative?
The inductor "resists" change in current. So say you measure the voltage across the inductor from point A to point B - the current is flowing in from A towards B. Now say the current is increasing. ...
- 2,009
4
votes
2
answers
2k
views
inductance value of a single turn thin circular coil
the question may seem simple but I haven't found any fitting formula yet. The problem is the following:
consider a single-turn, circular coil made of reasonably thin wire (diameter of the wire much ...
- 506
4
votes
1
answer
401
views
Calculating the internal inductance of a long wire without the concept of flux linkage
I did read the following questions: "Flux linkage inside of a conductor", "Derivation of self-inductance of a long wire" and "Trouble understanding fractional flux linkage"
The answers to them are ...
- 211
4
votes
1
answer
4k
views
Why do knots and kinks appear in domestic Iron power cords?
Our domestic steam clothing Iron has a rating of 2400W, and the house supply supply is 220V.
After about three months of use, the heavily cloth braided power cord of a new iron develops kinks, which ...
user167453
3
votes
2
answers
10k
views
Self-induction in a circular coil
There's a formula for self inductance: $$ L=\frac{n\Phi}{i}$$ where n is the number of loops.
But the book also says self inductance is directly proportional to $ n^2 $
I totally agree with the ...
- 366
3
votes
5
answers
19k
views
Transformer: primary side & secondary side current 180 degree out of phase
I am a novice in electrical engineering. I notice that in transformer the secondary side current & current referred to as primary are 180 degree out of phase from each other.
But why it is so, I ...
- 347
3
votes
1
answer
89
views
Why do we not have devices like inductors or capacitors to hold gravitational field? [closed]
I know that a capacitor can store electric field and an inductor can store magnetic field. So is there a way that gravitational field field can be stored in any such device. Also we do not have a law ...
3
votes
3
answers
11k
views
Reluctance and inductance are opposites, but both store magnetic energy?
Is there a (relatively) simple way to explain this? Inductance is the creation of stored magnetic energy that resists a change in current direction, but reluctance resists the creation of a magnetic ...
- 4,509
3
votes
2
answers
7k
views
A wobbly pan on an induction cooker, is it less effective?
According to the Wikipedia, one of the limitations of the induction cooker is that the bottom surface of the pot should be flat.
Accordingly, I commented on a question on Seasoned Advise, but I'd ...
- 69
3
votes
2
answers
246
views
Using Faraday's law twice
I have trouble understanding Faraday's law when there is an induced current which in turn induces another current in the same circuit. I shall illustrate my confusion with an homework problem and I ...
- 963
3
votes
1
answer
3k
views
Magnetic Flux conservation
My teacher said that after switch is shifted (after very long time), $\phi_i = \phi_f$ $\implies i_oL = i3L \implies i = \dfrac{i_o}{3} $ where $i_o$ is $\dfrac{\varepsilon}{R}$
So the initial ...
- 375
3
votes
1
answer
445
views
Inductance - a better analogy than the fact that it is similar to inertia
This question is to get a feel and good definition for what inductance actually is.
I have read about the analogy where inductance can be compared to inertia-that the flux through an inductor resists ...
3
votes
1
answer
216
views
What is the electric field around an inductor?
This question comes from this Walter Lewin video at 35:00 where he says "I'm going to confuse you even more" (and I suppose he somewhat succeeded). Walter Lewin claims there is an electric ...
- 8,640
3
votes
1
answer
782
views
External magnetic field produced by a solenoid at a given distance
I am trying to determine the external magnetic field of a solenoid at a given distance from its $z$-axis. Currently, I have been able to find the Biot-Savart law for a current loop:
$$B_{z}=\frac{\mu_{...
3
votes
4
answers
4k
views
Inductance in superconducting wires (and the math)
I'm very curious about inductors in general, and how similar they are to capacitors.
In the above picture the formula of current over time in an inductor with wire resistance $R$ is written.
I'm ...
- 33
3
votes
2
answers
846
views
Energy stored in the magnetic field
While deriving energy density of a magnetic field via using an inductor, why dont we consider the energy stored outside of inductor also?
As initially the field was there outside the inductor, (may ...
- 451
3
votes
1
answer
65
views
Is there a limiting frequency for transformers due to the time required to establish the magnetic field?
I was just wondering if there were some upper frequency at which a field would not fully form in a transformer and the output would be clipped.
- 31
3
votes
1
answer
173
views
Will adding a superconducting ring inside solenoid increases the inductance of it?
Consider a solenoid having $N$ turns and cylindrical length, a superconducting ring is placed inside having its plane perpendicular to axis of solenoid, if ring (having self-inductance $L$) is very ...
- 512
3
votes
3
answers
1k
views
Kirchhoff law and Inductors
I am struggling with using Kirchhoff's rule in circuits with Inductors. Looks like if you have an inductor, we have Electric field (E) that is created using a time varying magnetic field and that E is ...
- 1,481
3
votes
2
answers
266
views
Drum head coupled with an RLC circuit
I'm thinking about the possibility of an electroacoustic drum that would be tuned with some kind of RLC circuit.
The drum head would have an electromagnet attached to its center, which would be ...
- 133
3
votes
0
answers
194
views
Wave equation derivation in a transmission line
$$
V(x, t) = L\Delta x\frac{\partial I}{\partial t}(x, t) + \frac{1}{C \Delta x}\int{I_c(x, t) \; dt} \tag{1}
$$
$$
V(x + \Delta x, t) =\frac{1}{C \Delta x} \int {I_c(x, t) \; dt} \tag{2}
$$
$$
I(x) = ...
- 1,525
3
votes
1
answer
145
views
What do we mean exactly by inductance of two conductors?
I'll illustrate what I mean with a problem, but the question is not about this particular question. Instead I am looking for a general principle.
The problem is:
Calculate the inductance of a unit ...
- 326
3
votes
0
answers
124
views
Force vs Stroke for Open-ended Solenoid
If I understand correctly, the force (F) versus stroke (x) curve for a solenoid which is open ended (there is no plunger stop in the middle) is something like the curve below:
The plunger is forced ...
- 131