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Questions tagged [mutual-inductance]

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limit of mutual coupling

The two inductors are in parallel and are coupled magnetically. The equivalent inductance of the arrangement is, $$L_{eq}=\frac{L_1L_2-M^2}{L_1+L_2+2M}$$ This would obviously be zero when \$M=\sqrt{...
relayman357's user avatar
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5 answers
230 views

How to emulate effect of mutual inductance?

Background I don't have any background in electrical engineering. My knowledge is very superficial. I am simulating a circuit which has mutual inductance between two components. However, the software ...
FDGod's user avatar
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1 answer
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Lumped model of a load and source connected by two long paralel wires

I want to understand how to skecth an equivalent circuit model circuit composed of a load (resistor to make it simple) connected to a soruce bia two long paralel wires. Take the following figure as a ...
Santi Ospina's user avatar
0 votes
1 answer
78 views

Designing a voltage-current converter circuit to drive a coil as a mutual inductance antenna

I'm trying to design a voltage to current converter circuit to drive a coil antenna to transmit an analog signal through mutual inductance (very short range, around 3 inches). My frequency range is ...
Flint's user avatar
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3 votes
0 answers
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Resonant Coupling for Optimal Power Transfer

I am trying to read the following paper: B. L. Cannon, J. F. Hoburg, D. D. Stancil and S. C. Goldstein, "Magnetic Resonant Coupling As a Potential Means for Wireless Power Transfer to Multiple ...
ELec's user avatar
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1 vote
1 answer
150 views

Forms of Magnetic Noise Coupling

I was watching a video of Bob Pease discuss magnetic coupling of noise into the ground lead of an oscilloscope probe. See video at 5:40 https://www.youtube.com/watch?v=2vzvWUqUtb8 I noticed another ...
mrbean's user avatar
  • 812
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1 answer
88 views

What is a good way to mute antenna while keeping the aperture unchanged?

I have an 2D array of 64 antenna element. Lets say each antenna is connected to one RF chain. with this array total 64 parallel data streams can be transmitted with some pre-processing. When the load ...
MGM's user avatar
  • 103
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3 answers
190 views

About the I1N1 = I2N2 equation

I have a silly question about this equation which is very frequently used in ideal transformer relations. If I draw the electrical equivalent circuit of the core, then the MMFs of 2 coils N1I1 would ...
Aniket sen's user avatar
10 votes
2 answers
804 views

Parallel decoupling capacitors: Is inductance reduced?

Background In general, when placing decoupling capacitors in parallel, their capacitances add and their compound ESR is reduced (like for parallel resistors). But I am a bit uncertain if/how this ...
tobalt's user avatar
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4 votes
2 answers
353 views

Problem finding voltage in a circuit with mutual inductance

I'm trying to solve an example from Hayt's Engineering Circuit Analysis: let \$i_1=4i_2= 20\cos(500t-20°) \mathrm{\ mA}\$. Determine \$v_1(0)\$. Using \$k=\frac{M}{\sqrt{L_1L_2}}\$, I got \$M=0.6\ \...
ricardovaras_99's user avatar
1 vote
0 answers
229 views

Toroidal coil as current sensor

Is there a simple way to estimate the amount of flux that is caught by a toroid coil (filled by some core material, like powder iron for example), which surrounds a straight wire with a current ...
oliver's user avatar
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3 answers
1k views

Coaxial Cable with signal applied to shield and center conductor grounded

The standard way to drive a signal through a coaxial cable is to have the shield grounded, and a single-ended signal applied to the center conductor. (Throughout, I will assume that \$R_{term}\$ and \...
Math Keeps Me Busy's user avatar
1 vote
1 answer
155 views

magnetically coupled inductor equations

How come the mutual inductance for the v1(t) equation has a negative sign and the mutual inductance for the v2(t) equation have a positive sign? I don't properly understand how the signs of the self ...
Askari Abbas's user avatar
0 votes
1 answer
225 views

Non-ideal transformer transient state

So, I've encountered a problem that doesn't look that hard, but I simply can't solve it. I have a simple non-ideal transformer circuit and I want to compute V_0. What I was able to find so far are the ...
Lucas's user avatar
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2 votes
1 answer
527 views

Mutual inductance dot convention

I have a question regarding the dot convention, or more-so want to find out where I am getting it wrong. I start by defining the currents I1, I2, and I3. I1 goes through R1 and L1, while I2 is the ...
trunart's user avatar
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1 vote
2 answers
482 views

Mutual inductive coupling in a nodal admittance matrix

I have this question that has been haunting for quite a while now. To compute the nodal admittance matrix \$Y_N\$ of an electrical network, one can make use of the incidence matrix and the branch (or ...
Wallflower's user avatar
0 votes
2 answers
290 views

Why are inverter bus bars made overlapping?

A lot of literature on bus bar design suggests that bus bars should be made to overlap or have equal area such as this. The reason they mention is the total stray inductance falls due to increase in ...
Sambeet Panigrahi's user avatar
19 votes
8 answers
3k views

What precisely is the numerical (or any) meaning of mutual inductance and, is it useful, representative (of something) or important?

When we consider two inductors that are magnetically coupled, we sometimes talk about mutual inductance. As an example, consider two inductors (such as 9 μH and 4 μH) that are 100% coupled and produce ...
Andy aka's user avatar
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0 votes
1 answer
59 views

How will a PWM controlled relay affect a 800VA transformer on the primary side compared to the secondary side?

Application: A machine that seals boxes with plastic wrapping. The box is sealed by applying a heating element to the plastic for a few seconds. I have a 800VA (220VAC to 54VAC) transformer connected ...
user3760399's user avatar
1 vote
5 answers
2k views

Mutual Inductance Practical Explanation

I can't understand why the Mutual Inductance is measured in Henry. The self inductance of a coil is the abillity that has a coil to create a magnetic field that produses a voltage on itself so to ...
DarkKnight's user avatar
0 votes
0 answers
879 views

The function 'ddt' in LTspice frequency simulation

I have previously used the time derivative defined by LTspice in a time domain simulation, and I was wondering if this function could be used in frequency domain. If yes, what does it do exactly? I ...
Wallflower's user avatar
1 vote
1 answer
312 views

Taking into account the mutual inductive coupling analytically in LTSPICE

I am trying to take into account the mutual inductive coupling between three turns in LTspice differently. Instead of defining the inductive coupling coefficient K, I am using the analytical ...
Wallflower's user avatar
1 vote
1 answer
498 views

Can someone explain the dependence of coupling coefficient to inductance value to me? It seems counter intuitive

According to the formula \$K=M/\sqrt{L_1 L_2}\$, it seems that k is inversely proportional to the inductance values of the two coils. However, it seems to me that a coupling between two 2uH inductor ...
needbrainscratched's user avatar
1 vote
2 answers
262 views

Constructing Coupled Inductors with Particular Coupling Coefficient

I'm curious about the design of RF transformers with purposely designed non-unity coupling coefficient. I can see how this would be done in an IC, but how feasible is it at the discrete component ...
LetterSized's user avatar
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0 votes
1 answer
995 views

Common-mode choke on LTSpice

Can someone suggest to me how to select a three-phase common-mode choke with self and mutual inductance in LTSpice?
Ady's user avatar
  • 83
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2 answers
274 views

Confusion in modelling of total loop inductance of a rectangular loop

I was reading an article about partial and total loop inductances from this site and in a section where for calculation of total inductance of a rectangular loop is given as: In each portion of the ...
user215805's user avatar
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0 votes
1 answer
209 views

Regarding Magnetic coupled circuit

Here, all the initial conditions are : i1(0-)=0A and i2(0-)=0A When t≥0, the current i1(t) and i2(t) starts flowing. From my assumption, steady state value of i1(t) is 10A but what happens to i2(t)? ...
Camila's voice's user avatar
1 vote
1 answer
125 views

Magnetic coupled circuit

I am solving this circuit and according to the dot convension,the j6 ohm and j8 ohm have opposite polarities. Applying kvl to both loops, I got, 10 = j5I1 - j3I2 + j3I2 Or, I1 = -j2 A But I am stuck ...
Camila's voice's user avatar
0 votes
0 answers
66 views

Electrical conductivity circuit help, with two solenoids

I have a project im working on but cant seem to figure out the basic of the circuit. The principal of the circuit is two solenoids wrapped around a chemistry glass making a magnetic field. The purpose ...
Ben's user avatar
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0 answers
146 views

Why does LTSpice take so long to solve this circuit?

Using a technique to model transformers for a wide frequency range, I got at a circuit like this one: https://1drv.ms/u/s!AhR86nrv-ZA7ivoz9BZIoXfs4GwXIQ?e=L6mcKd LTSpice takes a long time to solve ...
Luiz Oliveira's user avatar
-1 votes
1 answer
156 views

Calculating inductance using PEEC Model

I'm learning of how inductance is modeled in wires by breaking them down into smaller filaments. I don't understand how the different inductances add up. Say we want to calculate the total inductance ...
Mehdi's user avatar
  • 109
0 votes
1 answer
75 views

Why Doesn't the Current in a Transformer Diverge?

I just started learning about mutual inductance and transformers, and I haven't been able to find the answer to this question. I suspect it's really basic, and that I'm just missing some understanding....
AlexP's user avatar
  • 3
1 vote
1 answer
352 views

Understanding of coupling coefficient and power transfer efficiency

I am a bit confused about my derivation to get power efficiency from the coupling coefficient. The coupling coefficient \$k=M/\sqrt{L_1L_2}\$. $$ V_2=M\frac{dI_1}{dt}=L_2\frac{dI_2}{dt}\\ V_1=M\frac{...
ONLYA's user avatar
  • 163
1 vote
2 answers
398 views

Analysis of three phase star star connected transformer

What is going on this circuit(below) and what would be current measured by ammeter(zero or non zero)? Description- These two transformers winding are star star connected and a balance sinusoidal ...
user215805's user avatar
  • 1,184
1 vote
0 answers
78 views

Loop inside a loop, where is the mutual inductance greatest?

I had a question while working a problem as to where the mutual inductance of a circular loop inside a rectangular loop is greatest. Is it at the center, because the magnetic field of all four wire ...
Hulk Remade's user avatar
0 votes
1 answer
235 views

Mutual inductive coupling and proximity effects

I am struggling a bit to differentiate between proximity effect and mutual inductive coupling. Proximity effect: if a conductor is carrying an alternative current the nearby conductors will witness an ...
Wallflower's user avatar
0 votes
1 answer
113 views

Why did the designer of this flyback circuit choose to set the oscillation frequency as high as possible with the smallest resistor tolerated?

This circuit uses a current mode controller with an oscillation frequency response of: In the circuit, the designer chose to use a 10nF cap, with a 680 ohm timing resistor, which according to the ...
James S's user avatar
  • 161
1 vote
1 answer
94 views

Wirless Power Tansfer Circuit

Hello so my university is closed because of covid. I am allowed one day into their labs to build and test my WPT device. My Tx is very large compared to my Rx. I have tested their inductance with a ...
cj91's user avatar
  • 155
2 votes
3 answers
341 views

Two questions about an AC electric circuit: Have I interpreted the dots correctly and where does the negative sign come from?

I asked this question over at the Physics Stack Exchange (https://physics.stackexchange.com/q/549814/263454) and I thought that it might stand a better chance of being answered here. So I am looking ...
truth_searcher's user avatar
2 votes
1 answer
1k views

Thevenin equivalent with mutual inductance

I was practicing for the exam I found a problem in the book as follow : I want to find the voltage Vth so here is what I did : When finding the Vth I didn't ignore the dependant voltage source in ...
Mhd Ghd's user avatar
  • 65
0 votes
1 answer
2k views

Mutually coupled inductor modelling in cadence

I used two methods to model two mutually coupled coils. Method: 1) Using 'mind' cell from analogLib. It basically lets you define a coupling coefficient k value. Method:2) Using 'Xfmr' cell from ...
Drake's user avatar
  • 1
0 votes
2 answers
2k views

How to design wireless charging coils so they are resonant?

I am continuing from this question: What can I use to increase efficiency of inductive wireless energy transfer instead of factory manufactured ferrite plates? I am trying to make somewhat efficient ...
Martynas Žiemys's user avatar
0 votes
2 answers
248 views

What can I use to increase efficiency of inductive wireless energy transfer instead of factory manufactured ferrite plates?

The Context I am a hobbyist with no education in electrical engineering. I am working on a DIY project trying to make water resistant rechargeable bicycle lights. I am doing this as a hobby for fun ...
Martynas Žiemys's user avatar
0 votes
1 answer
423 views

Equivalent circuit of identical transformers connected in parallel or series

I'm trying to figure out how to solve the equivalent circuit for two identical transformers connected in series or parallel on the primary and secondary. Mainly I want to know what the equivalent ...
DSho3's user avatar
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1 vote
1 answer
734 views

Transformer's Primary and Secondary Voltages

In general, which is the phase relationship between the primary and secondary voltages of an ideal transformer? Does it depends on the dot convention?
Kinka-Byo's user avatar
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1 vote
1 answer
2k views

Dot convention meaning

I have two questions about dot convention for the ideal transformer. I have understood how to use them in writing the voltage drops on the coils, but I have some doubts: 1) Which is the physical ...
Kinka-Byo's user avatar
  • 3,550
0 votes
1 answer
700 views

Autotransformer vs Inductive Divider

Which is the advantage of using an autotransformer instead of a simple inductive divider?
Kinka-Byo's user avatar
  • 3,550
0 votes
0 answers
145 views

Total phase inductance of three phase reactor

Consider a three phase reactor (inductor) using E-I or E-E laminations with phase winding on each limbs. Now inductance of R phase is given by: Lr=Lrr+Mry+Mrb Lrr: Self inductance of R-phase Mry: ...
chatty85's user avatar
1 vote
1 answer
123 views

Mutual inductance

I am confused about derivation of the next formula The question is about Cm term. We have coupled inductors. The voltage across first coil is And I am ok with it. I understand it. I know ...
Salekh's user avatar
  • 63
1 vote
2 answers
305 views

Resultant voltage function through two opposing coils with mutual inductance

So my question is about the type of relationship in a particular circuit. I would like to know if it is linear or something else like a power. The circuit in question is a pair of adjacent, mutually ...
user198606's user avatar