All Questions
124
questions
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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
0
votes
1
answer
115
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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
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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
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111
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How to find the canonical equations of the RLC circuit
First, I consider the LC circuit with an ion in the capacitor, which is like this:
The current $I$ can be derived easily by using Shockly-Ramo theorem
\begin{equation}
I = -\frac{qp}{dM} + C\dot{U} \...
- 68
0
votes
1
answer
585
views
Inductor EMF direction
I have some serious troubles with understanding the EMF in inductor.
Assume we change the current from value $I_0$ to zero by rotating the tumbler of the source.
Then why should we consider the EMF ...
- 258
2
votes
1
answer
290
views
Mutual inductance - induced magnetic flux in the primary
Let there be two coils, L1 (with self inductance L1), and L2, with self inductance L2.
The first coil is connected to a sinusoidal supply, and the second one is connected to a resistor load, as shown ...
- 21
2
votes
3
answers
535
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
3k
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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
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?
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201
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The self inductance of the motor of an electric fan is 10 H. In order to impart maximum powr of 50 Hz, it should be connected to a capacitance of [closed]
how can i solve this
(*)The self inductance of the motor of an electric fan is 10 H. In order to impart maximum powr of 50 Hz, it should be connected to a capacitance of
what is the concept behind ...
- 15
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votes
1
answer
61
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Behaviour of inductor (understanding equation)
If an inductor is connected to A.C. source (thinking no resistance is there), and if we travel across circuit there is voltage drop, and it is said
$$V=L\frac{\text dI}{\text dt}$$
How we write this ...
- 662
0
votes
4
answers
1k
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How to calculate the Force (in Newtons) produced by a solenoid?
How would I calculate the force on an object (in Newtons) that is under the influence of an electromagnetic field produced from a solenoid? I know it would involve using the equation $B=(μNI)/L$ to ...
0
votes
1
answer
76
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A misunderstanding concerning self induction of an inductor
If there is an inductor in a certain electrical circuit, from Faraday's Law we know that $$ \oint \vec{E} \cdot \vec{dl} = -\frac{d\phi_{magnetic}}{dt}$$
I see everywhere that when doing this line ...
- 1,038
1
vote
3
answers
597
views
Intuition in an LR circuit -- Why does rate of increase in current decreases with time?
Consider the below LR circuit.
The current law for the circuit is:
$$i=\frac VR(1-e^{- \frac {Rt}L})$$
And Voltage across inductor is:
$$L\frac {di}{dt}=V(e^{-\frac {Rt}{L}})$$
This means that the ...
- 1,568
1
vote
2
answers
445
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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}
...
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