All Questions
34
questions
0
votes
3
answers
62
views
Can an inductor increase circuit current?
Suppose there is a simple circuit with a resistor, battery and inductor. The question that came to me is, by opening the circuit breaker, can the inductor be used to oppose and slow down the circuit ...
0
votes
1
answer
53
views
Why doesn't current flow stop in LC oscillation?
Why doesn't current flow stop in a LC circuit? It is supposed to stop when the magnitude of emf developed across capacitor is the same as the inductor, right?
0
votes
0
answers
50
views
What logic is being used in Bleaney & Bleaney to prove the reciprocity theorem for mutual inductance?
I'm currently reading Bleaney & Bleaney 3rd Ed. On pg 136 they discuss the case of 2 coils. Their logic is as follows:
If a second coil is brought near to a coil carrying a current $I_1$, there ...
- 126
0
votes
0
answers
29
views
Is AC voltage across transformer pi shifted?
Suppose the voltage in the primary coil in a capacitor be
Vprimary = Vosin(wt)
According to my understanding, as the (AC) current in the circuit increases, the Magnetic flux across the secondary ...
- 153
0
votes
0
answers
26
views
Determining the condcutivity of a material by method of contactless resistance caused by putting a sample rod in the inductor of an RLC circuit
I'm doing an experiment where I'm trying to determine the conductivity of a material by putting a sample rod in the center of a coil which is a part of an RLC circuit with an AC generator.
I was told ...
1
vote
1
answer
220
views
Current and Magnetic Poles of a Solenoid (Diagram) & Right Hand Thumb Rule
Well, my doubt's pretty elementary.
Firstly I wanted to confirm whether both the cases, as illustrated in the picture, are correct. I've darkened the part of each coil that faces us. Using the clock-...
- 72
1
vote
1
answer
73
views
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...
$$\phi_B=...
- 187
2
votes
4
answers
250
views
Inductor connected to an AC source
Consider an inductor connected to an AC source, $V=V_0\sin\omega t$.
Let the the switch in the circuit be closed at $t=0$. Then by Kirchoff's voltage law,
$$
V-L\frac{dI}{dt}=0
$$
where $I$ is the ...
- 23
0
votes
2
answers
216
views
Current through a coil due to Electromagnetic Induction
If we change the magnetic flux through a coil -->
Will any current flow through this coil if it's two terminal is not connected to any kind of load, i.e - It is not in a closed loop.
If the answer ...
0
votes
0
answers
62
views
Current in primary circuit when diode in secondary circuit is reverse biased
Let's say we have an ideal transformer with a diode in the secondary circuit:
If the diode is reverse biased, there would be no current in the secondary circuit, which would mean that there is no ...
- 3
1
vote
3
answers
442
views
How can it be justified that the phase difference between voltage and current for inductor is $\pi/2?$
The inductor is an ideal one, the phase difference is with respect to current, and the voltage varies by the law $V=V_Lsin(\omega t).$
One can prove that the current function will come out to be $I=...
- 480
0
votes
1
answer
68
views
Is their an inherent flaw in using a step down transformer for a coil gun
I am currently in my first year of an engineering program so just recently learned about the many wonders of electromagnetism. For a school project this year I went on to build a coil gun using the ...
0
votes
1
answer
188
views
Is self-inductance dependent on geometry? Is $\Phi$ net flux or just flux due to cirucit?
Self-inductance of a circuit is defined as $L=\frac{\Phi}{I}.$ But it is not clear what $\Phi$ (read phi) is. Is it net magnetic flux or flux due to the magnetic field created due to current in the ...
- 480
1
vote
2
answers
515
views
What is the amplitude of current in LC oscillations
Since there is no resistance in an LC circuit (not attached to an AC source), what's stopping the current from rising to infinite. And if resistance is provided by the inductor by self induction, then ...
- 105
0
votes
1
answer
115
views
Is an increase in inductive current caused due to an increase in magnetic field?
I'm studying Inductive current in high school. I learned the Faraday law, and that the voltage produced is equal to the delta of magnetic field flux over time.
So, I was curious about this topic and ...
- 3
0
votes
0
answers
12
views
How to find the canonical equations of the series RLC circuit? [duplicate]
First, I consider the LC circuit with an ion in the capacitor, which is like this:
The current $I$ can be derived easily using Shockly-Ramo theorem
\begin{equation}
I = -\frac{qp}{dM} + C\dot{U} \ \ ...
- 68
0
votes
1
answer
2k
views
When an iron core is placed in a solenoid, why does the current increase? [closed]
Does the flux of the coil cut the soft iron core and generate emf in it? I am confused over the fact that since a stronger magnetic field, shouldn't the current increase. I believe the decrease in ...
2
votes
3
answers
534
views
Why can't the current in a solenoid be changed rapidly?
Why can't the current in a solenoid be changed instananeously? My reasoning is since the current in a solenoid is given by a integral:
$$I(t) = \frac{1}{L} \int_{t_0} ^{t_f} V_Ldt$$
then if $t_f = t_i ...
- 548
2
votes
2
answers
573
views
Does an inductor stretch or compress when a current is passed through it?
If an inductor is given to you and it is connected across a battery without any resistance in the circuit,then will the inductor stretch,compress or remain the same length?
0
votes
1
answer
52
views
Inductor Behavior for Voltages
When a DC voltage source is connected with a pure inductor.
And the switch is closed
We get a change in voltage across inductor and along with it a also an attempt to change the current across the ...
- 1,441
1
vote
3
answers
319
views
Significance of sliding switch in a LR circuit
The following image and statement are from my textbook Concepts of Physics on the chapter "Electromagnetic Induction", topic 38.6 "Growth and decay of current in an LR circuit", ...
- 5,306
0
votes
2
answers
101
views
Contradiction about the direction of magnetic force
I have encountered two contradictory directions for the force felt by current in a wire immersed in a uniform magnetic field.
Halliday says the force should be to the left in the situation pictured ...
- 41
0
votes
1
answer
133
views
Phase difference
Is there a phase difference between the magnetic field and the current producing this field?
I have simulation results for three-phase transformer at different frequencies. The spectrum of the ...
- 1
0
votes
1
answer
180
views
AC currents for self-inductance of a wire
I've been currently reading some stuff on self-inductance of a wire. There are different regimes where different approximations are used. For the AC currents the notes state that an approximation can ...
- 183
1
vote
4
answers
4k
views
Why isn't there any current in the primary if secondary circuit is opened in a transformer?
Consider an ideal transformer, with no load/resistor attached on the secondary (ppen circuit). It is said that the primary would act as if it is an open circuit too, thus no current flows through the ...
user215726
4
votes
2
answers
537
views
What does 'Oppose a Change in Current' really mean from Lenz Law?
We all know what Lenz Law is, but I have a bit of trouble conceptualizing the phrase above. Does 'Oppose a Change in Current' means it will take more time for the current to increase to its maximum ...
user215726
1
vote
1
answer
77
views
Inductors in AC circuit
We know that the current varries in an a.c. circuit if we connect an inductor to the circuit when the current is maximum the inductor oppose the current and tries to decrease the current and when ...
- 31
0
votes
3
answers
1k
views
Current in an AC circuit with only an inductor
In an AC circuit with only an inductor, we have a current that lags behind the EMF. So, at time 0 we have zero emf and max current. But in realty, how is this possible? How can we have a current ...
- 329
0
votes
1
answer
557
views
Electromagnetic induction in varying current
I know about Faraday's Law and how it states that an electric field will be produced if it will sense a change in magnetic flux that there are other sources of electric field except for an electric ...
- 99
1
vote
2
answers
3k
views
Why is the induced current greatest when a generator's loop is in the direction of the magnetic field?
This is a topic that has been confusing me for a while now.
take this picture for instance
We know that a current is induced when a conducting loop experiences a change in magnetic flux. So I ...
- 193