All Questions
25
questions
0
votes
1
answer
50
views
Voltage drop across an ideal inductor
I was afraid to type the title of the question though there are lot of answers to similar questions. I spent half a day going reading these questions and trying to understand the answers posted and ...
- 65
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
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
1
answer
182
views
Are we always allowed to treat an inductor as a battery with the same voltage?
When there is an induced emf, Kirchhoff's Loop Rule no longer is true, because electric fields are nonconservative when there is an induced current, as stated by Faraday's Law:
However, I have seen ...
- 323
4
votes
1
answer
299
views
Why can voltages be summed around a circuit if there is magnetic induction?
So there is this class I'm attending on Electronic Instrumentation which involves mostly circuit analysis. For example, RCL circuits, and circuits that also contain opamps, transistors, diodes, etc. ...
- 117
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
2
answers
435
views
Is the voltage drop across an inductor in a purely inductive circuit equal to $X_L\times I$ or back EMF?
In a purely inductive circuit, due to Kirchoff's voltage law we say that voltage drop across the inductor is equal to (negative of) applied AC voltage. However whenever we calculate the voltage drop ...
- 21
0
votes
1
answer
1k
views
Formula for The Voltage of a Coil
I've seen 2 different formulas being used for the voltage of a coil in a circuit. The first one is $$U_L=L\cdot\dot{I}$$ and the second one is $$U_L=-L\cdot\dot{I}$$ The first formula was used in a ...
- 3
2
votes
2
answers
3k
views
I have a doubt in applying KVL when an inductor comes to play in a circuit
When we apply KVL in a circuit containing R and L elements connected to a battery, we write the voltage (or EMF?) across the inductor as EMF= L di/dt. But, according to Faradays law and Lenz law, we ...
user281845
1
vote
2
answers
446
views
Does Ohm's Law still hold in the presence of a time varying magnetic field?
Ohm's law is often motivated by the microscopic relation
\begin{align}
\vec{j} = \sigma \vec{E}
\end{align}
From this you can easily derive
\begin{align}
U = RI
\end{align}
, given that
\begin{align}
...
- 6,773
1
vote
2
answers
410
views
How can current flow in a circuit if back emf is equal and opposite to applied voltage?
Ok, I've seen this question on this site before and other forums as well.
A similar argument can be made if a resistor is connected to a voltage source through wires. The voltage across the resistor ...
- 11
1
vote
1
answer
285
views
How is the rate of current change in an inductor present in a circuit maintained / decreased?
Considering an ideal circuit of DC voltage source and an inductor connected together with a switch in between them. When the switch is closed at t=0 the current starts increasing which causes induced ...
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
1
vote
1
answer
456
views
Electrons in an Inductor
What basically happens to the electrons, does the magnetic field produced by the electron moving in the inductor affect itself. what are the forces involved? Please elucidate the mathematics.
The ...
- 455
4
votes
2
answers
539
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
2k
views
Relation between Voltage and EMF of a solenoid
I've been working an a senior design project for school that uses solenoids, I needed to characterize the solenoids since they came from china and didn't have a datasheet. One of the tests that I ...
- 1
1
vote
3
answers
4k
views
Crossover frequency in RC filter circuits
When the resistor's voltage equals the capacitor's voltage, crossover frequency is defined to be $1/(RC)$. I am aware that below crossover frequency, there will be a low pass area where only low ...
- 81
2
votes
1
answer
11k
views
Is the number of turns in a loop part of the magnetic flux?
In all both my physics textbooks, the number of loops $N$ is left out of the equation for magnetic flux $\phi_B = \int_s \vec B \cdotp\hat n dA$ and only when calculating the Emf induced by an ...
- 411
6
votes
3
answers
4k
views
Why do Capacitor Inductor circuits Oscillate instead of reaching equilibrium?
When the capacitor is fully charged there is a potential difference between its poles and that creates a current.
This current would create a magnetic field that is changing in the Inductor (because ...
- 411
0
votes
4
answers
1k
views
Spherical magnet inside a solenoid
When passing a bar magnet through a long solenoid why is it that the induced emf when the magnet is in the middle of the solenoid is zero? And if a spherical magnet is put inside the solenoid, will ...
- 27
2
votes
1
answer
7k
views
Transformers - Why more coils in second coil causes more voltage [duplicate]
I am learning about magnetic induction and transformers.
I have coil1 which uses AC to create an oscillating magnetic field.
I have ...
- 153
0
votes
1
answer
297
views
Self inductance & time constant formula
Is this a correct formula for calculating the induced EMF of a wire after the current stabilizes/ or while it stabilizes in the beginning of a DC circuit?
What is the difference between the above ...
- 1,110
0
votes
1
answer
188
views
EMF due to self-inductance? [closed]
I'm trying to calculate the induced $-V$ in a DC circuit when current starts to flow, and reaches it's maximum value.
The inductance of the conductor is 1000nH it carries large amounts of current (...
- 1,110