All Questions
124
questions
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52
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How to find magnetic permeability of a mixed core?
Inserting a ferromagnetic rod into the core of an inductor increases its inductance. If the change in inductance is known, the following equation can be used (or so I assume) to find the relative ...
1
vote
3
answers
459
views
Does the unit "volt-seconds" have any interesting interpretation?
I was contemplating the units of capacitance and inductance in electrical circuit theory and noticed something that bugs me. Although there are many equivalent ways to write the farad (seconds per ohm,...
- 113
0
votes
2
answers
41
views
If we change the direction of the connections in a step-down transformer, will it become a step-up transformer?
If we change the direction of the connections in a step-down transformer, will it become a step-up transformer?
1
vote
1
answer
52
views
How can Current Flow through the Inductor in the AC Circuit? [duplicate]
It's said that if the inductor is connected to the alternating voltage source, alternating current will be created in the circuit. Changing magnetic flux through the inductor will induce a voltage as ...
- 515
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0
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27
views
Why are partial derivatives of Energy and Co-Energy with respect to x opposite numbers?
In a system where the flux linkage $\lambda = \lambda(x, i)$ is a function of dispalcement $x$ and current $i$.
Its energy is defined as
$$
W = \int_{0}^{\lambda} i(\lambda', x)d\lambda'.
$$
Its co-...
2
votes
2
answers
333
views
Inductance of air core inductor with and without load
I have an air core inductor whose inductance , as measured with LCR meter, is 45.1uH and quality factor is 4.4. When i place an Aluminum alloy (which is a Non-magnetic Material) as Load inside the ...
- 21
4
votes
1
answer
64
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
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
1
vote
0
answers
19
views
Doubt in RL circuit and Kirchoffs law [duplicate]
We know that kirchoff's second law is based on the fact that in any closed circuit: $$\oint \vec{E}\cdot\vec{dl}=0$$
Now let us take a simple LR cirucit with one battery $E$,resistor $R$, inductor $L$....
- 2,042
0
votes
1
answer
111
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Doubt in the mode of action of inductor in the RL circuit
I feel that my initial question was slightly incoherent and not precise. So instead of making addendum to the question which is making it lengthier, I am editing it completely. So, sorry about that.
...
- 436
3
votes
0
answers
194
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Wave equation derivation in a transmission line
$$
V(x, t) = L\Delta x\frac{\partial I}{\partial t}(x, t) + \frac{1}{C \Delta x}\int{I_c(x, t) \; dt} \tag{1}
$$
$$
V(x + \Delta x, t) =\frac{1}{C \Delta x} \int {I_c(x, t) \; dt} \tag{2}
$$
$$
I(x) = ...
- 1,525
2
votes
1
answer
123
views
Why is the product of the $L$ and $C$ matrices for coupled transmission lines diagonal?
Background - transmission line
$\newcommand{\ket}[1]{\left \lvert #1 \right \rangle}$
A transmission line can be modeled as an infinite sequence of inductors and capacitors:
...
- 24.6k
2
votes
4
answers
250
views
Inductor connected to an AC source
Consider an inductor connected to an AC source, $V=V_0\sin\omega t$.
Let the the switch in the circuit be closed at $t=0$. Then by Kirchoff's voltage law,
$$
V-L\frac{dI}{dt}=0
$$
where $I$ is the ...
- 23
0
votes
4
answers
200
views
Why $di/dt$ in inductor circuit reduces gradually after closing the switch?
When we close circuit having an inductor, an induced emf is generated across the inductor which opposes change in current through the circuit. This back emf depends on rate of change of current $di/dt$...
1
vote
2
answers
224
views
Doubling the length of a solenoid doubles its inductance. Two identical solenoids in series have up to four times the inductance due to M. Why?
The inductance of a long solenoid with $N_o$ turns and a length $l_o$ is
$$L_o=\pi r^2 \mu_0\frac{N_o^2}{l_o}$$
If I now make a new solenoid, $L_{new}$, with double the length of the original ($l_{new}...
- 1,581