Inductance Definition and 460 Threads

Hi, I know that the permiability (mu) changes as the core material saturates and I would have thought L1 = N12 / reluctance L2 = N22 / reluctance and they'd both share the same reluctance length, this would indicate to me that L1 and L2 are only a function of mu. Is this correct? I know also...

Hi, So if you wind a bifilar core in parallel and: connect it up in series, then it will have twice the N of if you connected them in parallel, i.e. The inductance is proportional to (2*N)^2 rather than just N^2, as connecting them up in parallel just increases the cross sectional area of the...

Odd question, would anybody know what would happen if a parallel plate capacitor (good conductor) had a soft magnetic material (fairly poor conductor) as a dielectric? What would be the DC/AC electrical characteristics of this?

I was reading textbook and felt confused about this-- when trying to deal with inner inductance of transmission line, only the fraction (x/r)^2 of total current, which interlock with magnetic lines should be considered. However, isn't the inductance or even flux linkage an intermediate...

Homework Statement A resistor and a capacitor are connected in series to a variable frequency supply. A voltmerter is connected across the inductor and another across the resistor. The supply voltage is kept constant as frequency of supply is increased. State and explain the changes in the...

A d.c circuit consists of a switch, lamp and inductor. The inductor is replaced with an inductor with twice the number of turns in the coil of wire, nothing else about it is changed. State the effect on A) maximum current B) the time to reach max current I thought increasing the turns would...

I know that- The change in current of primary coil changes the magnetic flux linked with the secondary coil and this an emf will be induced in secondary coil (which also has an inductor in the circuit) so current grows in secondary coil and the current in secondary coil produces magnetic field...

When they teach transformers, they give you the Ampere's law, the Faraday's law, etc. and then derive this well known formula L = μ * N^2 * A / ℓ. And everything is no nice, all these parameters are used to define some other relationships, like the concept of reluctance in magnetic circuits...

How to explain mutual inductance with the image I attached? There are two conducting frames, one has a source of DC and a variable resistor, the other just a galvanometer. What I should conclude from this picture that the flux is F1=alpha*I and F2=c*F1, and Ein=-M*dI/dt. How? Is the current I...

Homework Statement Homework Equations The Attempt at a Solution

I found two ways to solve this problem, but I get two different solutions, it's confusing because I can't see the flaw in wrong solution. 1. Homework Statement Long cylindrical inductor of diameter D1 and inductance L1 is connected to battery and creates magnetic field B1. Inductor is then...

Hi To detect position of a metal we can use the eddy currents induced by a current carrying inductor. It is described in this link. http://www.marktec.co.jp/e/product/ndt/ect/principle.html Would this still work if the target is a magnet enclosed in a metal casing. Basically I need to detect...

Could someone give me an intuitive explanation as to why the current lags the voltage in an inductive circuit. I can understand it through the equation E=ldi/dt. But how exactly does the current lag, on a molecular level?

Can't find an answer to my question. Why do capacitors are so special when it comes to purity, unlike resistors and inductors. I know the capacitor somehow impedes the inductance in the circuit, but how? I just began studying the ac theory, and it boggles my mind.

Hi All, I'm just trying to get my head around circuit theory at the moment (really, really basic stuff, like what a capacitor is etc) and I've run up against some difficulties in separating out some definitions. The main one I'm wrestling with right now is the difference between the inductance...

Hi, I'm been spending way too much time this weekend, wrestling with the equations provided in the paper [The mutual inductance of two thin coaxial disk coils in air, Babic S., DOI: 10.1109/TMAG.2004.824810], but I just can't seem to verify the results obtained in the examples in the journal...

Hello all, There are a million threads and a million Google hits out there on the topic of switching the polarity of an electromagnet. Very simple stuff. But none seem to touch on the issue of inductance. I am building a small linear actuator that will be a coil wrapped around a thin plastic...

Homework Statement A coil with zero resistance has its ends labelled a and b. When a current is passed through the coil the potential at a is higher than the potential at b. Which of the following would be consistent with this situation? (Note, there may be more than one correct alternative.)...

Homework Statement An inductance is connected across an AC current generator. Homework Equations v= L di/dt = Vsinωt The Attempt at a Solution i=∫di= V/L ∫sinωt dt= -V/ωL cosωt This is what is written in my book. But wouldn't there be a constant at the end of the indefinite...

Good evening all, I am looking for some clarity on a question I am answering at the moment. An inductor of negligible resistance and an inductance of 0.2H is connected in series with a 330ohm resistor to a 12v d.c. Supply determine: A - the time constant of the circuit B - the voltage...

I've been looking for a good formula to calculate the inductance of a multilayer solenoid within about 10% accuracy or greater. I've used several formulas derived from Wheeler's formula, as well as a few online calculators, however, my results seem to differ wildly depending on what formula or...

Homework Statement Find the mutual inductance between a coil with N loops and an infinite straight line with current I on its axis. Homework Equations M12 = M21 = flux 1/I 2 = flux 2/ I 1 emf = -d/dt flux i = emf /R R = eta*l/S The Attempt at a Solution I have done this...

In a DC circuit(Yes, keep going), when current starts to flow, and that current needs a bit of time to stabilize to its maximum value. Since there is change in current(increase) there is an increasing magnetic field, a changing flux... that will induce a -V to the circuit. Eventually when...

Homework Statement An inductor is connected to a 20.0-Hz sinusoidal power supply that produces a 50.0-V peak voltage. What inductance is needed to keep the instantaneous current in the circuit below 77.4 mA?Homework Equations X(L)min = V(rms)/I(rms) I(rms) = I(max)/√2 X(L) = 2pi*f*LThe...

Homework Statement Please see attached images. 2. Relevant Questions I'm fairly certain the mesh equations are incorrect. I'm having a hard time accounting for the mutual inductance and the voltage/current loss between each mesh. When we account for the lost voltage (using j300 in...

three inductors in-series, of increasing inductance , say 1μH , 10μH and 100μH , wire-gauge constant and wire has some resistance which is constant per unit length. Is it possible to make the middle inductor, (10uH), the hottest of the three by adjusting the frequency of the AC passing...

An inductor of negligible resistance and an inductance of 0.2 H is connected in series with a 330 Ω resistor to a 12V d.c. supply. Determine: (a) the time constant of the circuit (b) the voltage drop across the inductor after two time constants (c) the voltage drop across the resistor after...

Homework Statement A small, thin coil with N2 loops, each of area A2, is placed inside a long solenoid, near its center. The solenoid has N1 loops in its length L and has area A1. Find the mutual inductance as a function of θ, the angle between the plane of the small coil and the axis of the...

Homework Statement My textbook has two problems, based on the same premises, but the solutions manual solves each of them differently, so I was wondering why? Here are the two problems... 1. In the circuit shown in Fig. P29.49, the capacitor has capacitance C = 20μF and is initially charged...

Homework Statement Hi again guys, been stuck on this problem for a while now, thought it would be a simple bumping in some values in a given equation question but I can't get the correct answer :confused: Heres the problem: What is the inductance of a 600 turn coil wound on a core of cross...

Homework Statement A 5.0V battery is attached to an RL circuit. The current is given by the formula: I = V0/R(1-e-t/τ), where I0 is the steady-state current, and τ is the time constant for the circuit. Using the data table provided, determine τ, R, and L for this circuit. I(mA) | t(μs)...

Hello everyone, I want to have a simple example of an inductance calculation. The magnetic field normal to a filamentary circular current loop is not constant over the circle but if we approximate the value as that for the center, multiply by the area of the circle and divide by the current...

Hi there, I'm doing a home study course including a section on dynamic fields and waves. I am trying to understand how to find capacitance using initial charge, inductance and energy. From a previous section, I know I can find the maximum current using Um=1/2 LI2 However, I can't see...

Homework Statement Compute I1, I2 and I3 instantly after the switch is opened in the below attached circuit. Homework Equations The Attempt at a Solution I don't know L and I don't know E. All I know is the currents while the switch is closed. I can't find tau, which I...

Homework Statement I am designing a solenoid for a project to meet several specifications. I am attempting to induce an emf of approximately 2V in my circuit by moving a magnet in and out of the coil. I know the magnet has an approximate field strength of 1T. I am trying to determine necessary...

Hi, This is a cascode LNA. Please help me with the question in picture. Thank you.

Can some check my answer, please? I only did number 1 because I have no idea how to do number 2. NOTE: Calculators are not allowed, so no need to give the exact value. For example, if the answer has √2, just leave it as √2, instead of writing it as 1.41... Power source voltage e(t) =...

A coaxial cable is modeled as a long thin cylindrical shell with radius b concentric with a solid wire of radius a (the wire is inside the shell). Calculate the inductance of a length l of this cable. (Example 32.5 Here) ---> https://echsphysics.wikispaces.com/file/view/APPhysicsCH32.pdf...

Homework Statement Determine the resistance of a 0.2H coil used to replace the inductor if the circuits time constant falls to 0.55ms. Homework Equations l/R The Attempt at a Solution L/R = 0.2H/R = 0.55ms Transposing for R... R = 0.2/0.0055 = 36.36Ω is the resistance of the coil?

Self inductance of a coil : how does it happen ? I've got some hardtime trying to imagine how it happens , the phrase which confused the most while studying was "each turn acts as a small magnet ",so why does it change polarities at the moment of switching the circuit on or off ? Also the whole...

Hello! How do I calculate the capacitance of a twisted wire pair in 3D? The pair of wire would have two different dielectric(air and insulation) mediums and hence I am not able to figure out how to calculate it by hand. My plan was to create a 3D Model, mesh it and put it up in...

Homework Statement An inductor has an inductance of 0.45 H and internal resistance of 2.5 . If the H inductor is connected to a 120-V (rms) source at 60 Hz, what is the current (rms) through it? Homework Equations XL=2pi*f*L V=IR The Attempt at a Solution I don't have any idea...

Hello all, I do apologize if this is in the wrong section as this is my first post. If I have posted in the wrong area please let me know. I have a basic understanding of the concept of inductance but have read many formulas which I think are trying to express the same idea but from...

Homework Statement Homework Equations F = I\vec{l} \times \vec{B} \varepsilon = BLv The Attempt at a Solution Every direction i go seems real wrong F = I\vec{l} \times \vec{B} F = \frac{\varepsilon \vec{l} \times \vec{B}}{R} F = \frac{\varepsilon LB}{R} ma =...

Homework Statement Derive TEC between terminals "ab". Homework Equations The Attempt at a Solution I figured I'd add the mutual inductances to the inductors, and solve it as a normal RLC circuit, since no current is passing through the 80j coil, it's inductance wouldn't change...

Dear all, I would like to estimate the inductance of a rather arbitrarily shaped coil composed of multiple single loops. For example, I am wondering about the inductance of sandglass like coil which has many turns at the edge and less in the middle. The inductance of a single loop seems to...

why inductance's current represent with di/dt? ps) and how do you make image big...

Consider a solid cylinder of radius R. an varying current of current density δ flows through. what would be self inductance of that cylinder

Hi All, If anyone could help me with a problem I'm having, it would be great. I've been using Ansys Maxwell for about 6 months now, and I've gotten the hang of it. I mainly simulate 2 phase inductors. Until yesterday, I've had no problem, but for some reason, I'm not getting any...

The inductor below is conducting an arbitrary current, with the switch on. Suddenly the switch is set off and and voltage over the inductor raises to the negative infinity according to Vl = L*di/dt However, voltage is defined as energy per charge. V=J/C The energy stored "in" the...