What is Mutual inductance: Definition and 119 Discussions

Inductance is the tendency of an electrical conductor to oppose a change in the electric current flowing through it. The flow of electric current creates a magnetic field around the conductor. The field strength depends on the magnitude of the current, and follows any changes in current. From Faraday's law of induction, any change in magnetic field through a circuit induces an electromotive force (EMF) (voltage) in the conductors, a process known as electromagnetic induction. This induced voltage created by the changing current has the effect of opposing the change in current. This is stated by Lenz's law, and the voltage is called back EMF.
Inductance is defined as the ratio of the induced voltage to the rate of change of current causing it. It is a proportionality factor that depends on the geometry of circuit conductors and the magnetic permeability of nearby materials. An electronic component designed to add inductance to a circuit is called an inductor. It typically consists of a coil or helix of wire.
The term inductance was coined by Oliver Heaviside in 1886. It is customary to use the symbol



L


{\displaystyle L}
for inductance, in honour of the physicist Heinrich Lenz. In the SI system, the unit of inductance is the henry (H), which is the amount of inductance that causes a voltage of one volt, when the current is changing at a rate of one ampere per second. It is named for Joseph Henry, who discovered inductance independently of Faraday.

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  1. J

    How Do You Calculate Mutual Inductance Between an Infinite Wire and a Loop?

    Homework Statement Find the mutual inductance between an infinitely long wire and a single loop of wire separated by a distance d. (radius = a) Homework Equations The Attempt at a Solution I've adjusted the magnetic flux density to a coordinate system to make everything easier B =\frac{...
  2. M

    Optimizing Inductors in Series: How to Code for Mutual Inductance Coupling?

    Does anyone know how to code the following? I have six inductors in series and would like to couple them to one another. i.e. L1 1 2 1u L2 2 3 1u L3 3 4 1u L4 4 5 1u L5 5 6 1u L6 6 7 1u Ideally I'd like to do: K12 L1 L2 0.3 K23 L2 L3 0.4 K34 L3 L4 0.2 K45 L4 L5 0.5 K56 L5 L6 0.4...
  3. D

    Mutual Inductance and coupled coils

    Homework Statement For coupled coils in this arrangement (illustration attached), show L_{eq} = \frac{L_1 L_2 - M^2}{L_1 + L_2 - 2M} Homework Equations KVL (mesh analysis) The Attempt at a Solution As you can see, I get to a final answer - which is not exactly the same...
  4. K

    Square Coil, Round Hole and mutual inductance

    Homework Statement A square, single-turn wire coil L = 1.13 cm on a side is placed inside a solenoid that has a circular cross section of radius r = 2.77 cm, as shown in the figure below. Basically a big circle with a square in the center. The solenoid is 20.0 cm long...
  5. B

    How Do You Calculate Mutual Inductance Between a Filament and a Square Loop?

    Homework Statement Find the mutual inductance in air between a long straight filament and a coplanar square loop, 10cm on a side, with its nearest edge parallel to and 10cm from the filament. Homework Equations What equations should be best in solving this problem? The Attempt at a Solution...
  6. K

    Calculating Mutual Inductance of Two Rectangular Loops

    I am a student of the electrical engineering in the university of Munich. I tried to solve a homework but I have some difficulties. I have tried to use different methods. unfortunately, unsuccessfully. I will be very glad if you could help me. in fact I wanted to calculate the mutual...
  7. K

    Simple Mutual Inductance Experiment

    Hello All, I did a simple mutual inductance experiment recently which involving two coils (5 turns each) in series with a high frequency signal (MHz range) running through them. One coil is directly connected to function generator via a co-axial cable, and the other coil is connected to...
  8. S

    Mutual Inductance: Lenz's Law & Switch Effects

    In illustrating mutual inductance, there is a primary coil and a secondary coil, which houses an induced current. In applying Lenz’s Law to the direction of the secondary coil’s induced current, the status of the switch must be taken into account. If the switch is closed, does the secondary...
  9. D

    Mutual Inductance (ouch, my brain)

    Homework Statement During a 65 ms interval, a change in the current in a primary coil occurs. This change leads to the appearance of a 6.0 mA current in a nearby secondary coil. The secondary coil is part of a circuit in which the resistance is 12 . The mutual inductance between the two coils is...
  10. E

    Mutual Inductance and wire coils

    Hi..I am new here and I am really thankful for any help that I may get :blushing: I am stuck in a problem of mutual inductance. It seems fairly simple, yet I cannot get the correct answer. Two coils are close to each other. The first coil carries a time-varying current given by I(t) =...
  11. Antepolleo

    Mutual Inductance and Ampere's law

    It's electromagnetics time again. I'm horribly stuck on a homework problem. It has to do with mutual inductance, and I know how the problem works conceptually, but I'm having a difficult time with the mathematics. The problem:A very long (read: infinite) wire is a distance d from the center of a...
  12. P

    Mutual Inductance: Coil Wrapping Direction & Opposite Poles

    I have 2 inductors in series...iron core...iron yoke...with a capacitor in parallel. For best mutual inductance, does it matter which direction each coil is wrapped...or maybe a better question would be how do you insure that the poles will be opposite every cycle so they are not working...
  13. L

    Simple question about definition of Mutual Inductance

    I'm getting confused over the formal definition of mutual inductance. I've googled and searched a lot of sites, but I still don't understand, so I'm hoping someone here can explain it to me in plain English! In our lecture, this was the formula given for mutual inductance: L_{12} =...
  14. S

    Question regarding mutual inductance of two coil

    I have my question,solution and the problem I faced in the attachment that followed.Thanks for anybody that spend some time on this question.
  15. R

    Mutual Inductance of the cylinder coils

    Two coils are wrapped around the same cylinder form. When the current in the first coil is decreasing at a rate of -.242A/s, the induced emf in the second coil has a magnitude of .00165 Volts. What is the mutual inductance? What I did: E_2 = -M(\frac{d_i_1}{d_t}) .00165/-.242 = -M...
  16. M

    Mutual Inductance: Formula & Coaxial Loop Model

    Hi everyone, I'am trying to find the formulas of the mutual inductance of an one single layer coil (the cross section is rectangular i.e. the wire is rectangular or a round loop with rectangular cross section)on cylindrical winding form. Does anyone know how to calculate this mutual...
  17. O

    Calculating Mutual Inductance with Neumann Integral Problem

    I'm having problems trying solve this problem. Consider the two conductor system given below |----------------------------------------------------------------| | <------a-----> | | I2-> ______________...
  18. H

    How can I accurately calculate mutual inductance between a coil and a magnet?

    Hi, All: I am trying to calculate the mutual inductance between the coil (100 turns) and the magnet. Does anybody know any approaches that may lead a satisfactory answer. So far, I have been using Neumann's formula which is the formula for mutual inductance, M, between two loops. I...
  19. H

    How can I accurately calculate mutual inductance between a coil and a magnet?

    Hi, All: I am trying to calculate the mutual inductance between the coil (100 turns) and the magnet. Does anybody know any approaches that may lead a satisfactory answer. So far, I have been using Neumann's formula which is the formula for mutual inductance, M, between two loops. I...
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