Questions tagged [inductance]

The property of an electrical conductor through which a change in current through it induces an electromotive force in both the conductor itself as well as in any nearby conductors by mutual inductance. Also use more broadly for electromagnetic phenomena in solenoids.

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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 ...
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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) = ...
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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 ...
Prateek Mourya's user avatar
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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 ...
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flux threading through superconducting ring

I have been confused over the wording used in this paper describing RSFQ logic circuits: http://www.mukhanov.com/uploads/LikharevSemenov-RSFQReview_IEEETAS91.pdf From page 6: " If such a single flux ...
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Can an Opposing Current Create another Opposing Current?

In Inductors when current increases it's magnetic field induces a voltage which causes an opposing current that slows down the rise of the current that initially creates it, but can this opposing ...
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Dot convention inductors in series: what is going on

So I'm really confused with mutual inductors and dot convention. If your answer is going to be a link to any website I can assure I read them all and that only left me more confused. So here are my ...
Granger Obliviate's user avatar
2 votes
1 answer
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Does parasitic capacitance contribute to the magnetic flux?

When modeling a real inductor, typically the equivalent circuit is the following one: Source A series resistance and parallel capacitor is added. This model works very well to explain the following ...
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Variation of Permeability with DC magnetising Field

For any Powder core, as DC magnetising field increases, the initial permeability decreases known as "permeability roll off". For example for an MPP core- For MPP cores the initial ...
Frost ghost's user avatar
2 votes
3 answers
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If An Instantaneous Force Causes A Charged Particle To Briefly Accelerate, Does Self-inductance Decelerate It?

Consider the following example: A charged particle initially at rest briefly accelerates in the forward direction due to an initial force. At this point the particle is carried forward only by inertia,...
Schubert Rulet's user avatar
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Mutual inductance - induced magnetic flux in the primary

Let there be two coils, L1 (with self inductance L1), and L2, with self inductance L2. The first coil is connected to a sinusoidal supply, and the second one is connected to a resistor load, as shown ...
Jonathan's user avatar
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Magnetic field due to a double tape line

I have been asked to calculate the inductance of a double tape line : Now we know that $$ N\phi = LI$$ So let's calculate the magnetic field by assuming an amperian loop like this: $$\int B.dl = ...
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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 ...
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In series RLC circuit, does decreasing the capacitance value really make the circuit more capacitive circuit?

This seems very counter intuitive to me. How can decreasing the capacitance value make the circuit more capacitive ? The math tells me so : If $C$ decreases then $X_c = \dfrac{1}{\omega C}$ ...
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Does there exist a rigorous general mathematical proof for $M <\sqrt{L_1L_2}$?

Does there exist a rigorous general mathematical proof for $M <\sqrt{L_1L_2}$? Here $M$ is the mutual inductance between two conductors and $L_1$ and $L_2$ are their respective self-inductances. (...
Derby Moose's user avatar
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Why is the electric field inside a solenoid tangential?

I have been looking at some derivations for the electric field inside a solenoid. I know how to find it, but I don't get the symmetry argument used. This is often of the form: Since if we choose a ...
Quantum spaghettification's user avatar
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Calculating magnetic field strength for a very small electromagnet

I am trying to calculate the magnetic field (in tesla/gauss) of an electromagnet that is very small and has very few windings. For example 12 windings over 0.003 meters. I know this is not going to ...
EddieP's user avatar
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How Are Electromagnetic Waves Produced?

How EM waves are produced say by a capacitor of an LC circuit here if $E$ is increasing in upward direction? My thoughts Thought 1:- If E is increasing E flux is increasing thus B field must be ...
Gaurang Agrawal's user avatar
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Coilgun projectile force calculation

Please excuse me if I am completely wrong because I am a 9th grader but I hopefully am able to explain briefly about my problem. I was trying to create a function to calculate the Force of an iron ...
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Telegraphers' equations for lossy transmission line when $R$, $L$, $G$, and $C$ are frequency dependent

The telegraphers' equations are commonly written as $$\frac{{\partial v(z,t)}}{{\partial z}} + R\space i(z,t) + L\frac{{\partial i(z,t)}}{{\partial t}} = 0$$ $$\frac{{\partial i(z,t)}}{{\partial z}} + ...
Andy Ackland's user avatar
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1 answer
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Mathematical expression for self-inductance constant $L$?

Is there a mathematical expression for what the value of $L$ (self-inductance constant) is for a given geometry? I've tried to come up with something, but I don't know if it's right or not... $$\phi_B=...
JBatswani's user avatar
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What exactly is the formula of total flux linkage? Is it $dλ=dΨ *\frac{\text { Ienclosed}}{I}$ or $λ=N*Ψ$?

In Sadiku, he used the formula $dλ=dΨ *\frac{\text { Ienclosed}}{I}$ to determine the total flux linkage for coaxial cable for $ρ<a$ and for $a<ρ<b$, but I applied this formula for the ...
Elie Makdissi's user avatar
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1 answer
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In an $RLC$ circuit, where there are multiple components instead of a single resistor/inductor/capacitor how does impedance $Z$ is calculated?

If there is an $RLC$ circuit where some components are in series with one another and some components are in parallel with one another, how does the total impedance of the circuit is calculated? I ...
Raymonk Surya's user avatar
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Please clear up the following confusion about Faraday's law, electromotive force, magnetic inductance, and current

As the magnet moves from the outside, the magnetic flux that is linked to the circuit is [pi_0 sin(wt)]. We have listed a series of processes related to electromotive force, self-inductance L, and ...
Anthony Williams's user avatar
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What is the flux linkage or inductance or induced voltage per unit length of the hollow tube conductor surrounding the inner conductor?

What is the flux linkage or inductance or induced voltage per unit length of the hollow tube conductor surrounding the inner conductor in some section due to the current in the inner thin conductor? ...
Anthony Williams's user avatar
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1 answer
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Does the presence of a disconnected coil nearby affect the self-inductance of a coil under test?

Picture two coils in close proximity. They have the same dimensions and are located co-axially, with a small gap between then (like Helmholtz coils, but much closer together than in the standard ...
germ's user avatar
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Current through a capacitor in AC Circuits

I'm a little confused on the equation for the instantaneous current through a capacitor in AC circuits. My textbook has it as: $$i_C = \omega CV \ cos(\omega t + \pi/2) = -\omega CV \ sin(\omega t)$$ ...
vigilante_fresh's user avatar
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Inductance of a coated cylinder

Say we have an infinite cylinder, through which a current of intensity $I$ flows. Say this cylinder is coated with a conductive material, of negligible thickness, through which a current of the same ...
random person's user avatar
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1 answer
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Are we always allowed to treat an inductor as a battery with the same voltage?

When there is an induced emf, Kirchhoff's Loop Rule no longer is true, because electric fields are nonconservative when there is an induced current, as stated by Faraday's Law: However, I have seen ...
Akash's user avatar
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Why is the relation between voltage ratio and frequency a linear one in a lumped transition line?

In an experiment the cutoff frequency of a lumped transmission line is determined by measursing the ratio of the output/input voltages. The lumped transmission line is a ladder network of 40 ...
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Question about the impedance of a RLC circuit

I made an experiment with a RLC circuit, and I found the resistance, the capacitance, and the inductance with measures. So I decided to calculate the impedance of the circuit, depending on the ...
Corentin's user avatar
1 vote
1 answer
132 views

Definition of inductance and volume currents

If I have a uniform, infinitely thin current. The relationship between inductance and current by definition is: $\phi_{B} = L I$ Where inductance($L$) the proportionality constant between a wires ...
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Do transformers return current to source when magnetic field collapse at primary coil?

When we close the circut containing an inductor and a battery, the current starts flowing, which builds magnetic field around inductor, changing magnetic field produces its own current in opposite ...
Yogie's user avatar
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Inductance and Mutual inductance

Question: Three coils with inductances $L_1, L_2$ and $L_3$, as well as mutual inductances $M_{12}, M_{13}$ and $M_{23}$ are connected in series. What is the total inductance? The right answer is $L_1+...
MathLover's user avatar
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Which terms in the equations for dipole impedance include inductance/capacitance and velocity factor?

In the below equations for the impedance of a center fed half wave dipole, exactly which terms include self inductance/capacitance, and which terms cater for an antenna embedded in a homogeneous and ...
Andrew's user avatar
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1 answer
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Question on Faraday's Induction Experiment

We all know that moving a magnet through a loop of wire induces a current, like in this youtube experiment here. Similarly, we know that moving one solenoid (with a battery hooked up) through a larger ...
Programmer's user avatar
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Input voltage over frequency in lumped-element delay line?

In a lumped delay lines, there is a reflected wave from the end of lines if the terminating impedance isn't equal to characteristic impedance. Therefore, at the input, the input voltage $V_{in}$ is ...
Shefield's user avatar
1 vote
1 answer
174 views

Magnetic Flux of a lone solenoid and coaxial solenoids

If you run a current through a solenoid, does it have any magnetic flux on its own of does it need an externally produced magnetic field for there to be any net flux through the solenoid? The physics ...
Aidan's user avatar
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Deriving solenoid inductance using Faraday's Law

The inductance $L$ of a long solenoid of length $\ell$, cross-section area $A$, and turns per length $n$ is given by: $$ L = \mu_0 n^2 \ell A $$ where $\mu_0$ is the magnetic constant. I am currently ...
David Egolf's user avatar
1 vote
1 answer
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How does RF communication between electronic circuit elements affect the circuit?

The other day, a friend and I were looking at a simple resistor-capacitor-inductor circuit. As we were looking at the circuit, he mentioned that the capacitors and inductors "talked" to each ...
Abstract Acumen's user avatar
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Why we take the element $ds$ in self inductance of coaxial cable

I watched on a derivation of coaxial cable and when we want to calculate the self inductance per unit lengh we first find the flux of the magnetic field,so we take the integral $\int_{a}^{b}\vec{B}\...
Sagigever's user avatar
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Crossover filter gives weird results

I was analyzing results of an experiment on a crossover filter and I was trying to take into consideration the parasitic resistance of the inductor L (called $R_L$). I know the theoretical crossover ...
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Two questions about an AC electric circuit: Have I interpreted the dots correctly and where does the negative sign come from?

So I am looking at two mutually coupled circuits that are not at resonance. In particular I am looking at a pair of electric circuits discussed on pgs: 259 - 261 of the book "Electricity and Magnetism"...
truth_searcher's user avatar
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Velocity of an Object Accelerated by an Inductor

I am currently trying to build a coil gun as a class project (for an introductory programming/electronics class), and I want to be able to determine the launch angle necessary to send an object a ...
Isaac Krementsov's user avatar
1 vote
2 answers
107 views

Transformers and basic inductor physics

1) Why does resistor reduce the lag in a RL circuit? I understand why current lags by 90° with the voltage across the inductor. (After watching this) But I don't understand why that lag, would be ...
Aravindh Vasu's user avatar
1 vote
1 answer
73 views

Confusion regarding inductor connected to an AC source

Suppose I connect an inductor to an ac source. Now a time varying current is produced and this causes change in magnetic flux linked with inductor coils and hence an induced is generated. But why ...
Sharad's user avatar
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3 answers
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Understanding simple $LC$ circuits

I'm trying understand the physics of simple inductor-capacitor circuits such that there is just an inductor $L$ and a capacitor $C$ and a switch. Imagine first that the capacitor is fully charged and ...
Jamie Smith's user avatar
1 vote
1 answer
144 views

Why does a conducting cylinder spin when held next to a conducting ring around a solenoid?

My uncle showed me this video. I understand that the magnetic field from the solenoid induces a current perpendicular to it in the ring. However, I don't see why this current would result in a torque ...
spheroidic's user avatar
1 vote
0 answers
147 views

Is the flow of charges in inductor though electric field zero?

How electric field inside the wire of an inductor is zero (i.e. material of which loop is made — note material is assumed to be a superconductor), then how electrons flow in an inductor if electric ...
user avatar
1 vote
1 answer
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Why charge induction is limited to some amount?

Polarization occurs when a charge is placed next to a conducting object. When we ground the side of the object opposite the charge, that side becomes neutral. But this neutralization disturbs the ...
harman's user avatar
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