All Questions
17
questions
0
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2
answers
49
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Maxwell stress tensor on a capacitor late given a dielectric
Given a capacitor with large plates (area $A$) separated by a dielectric with relative permittivity $\varepsilon_r$ and thickness $g$, I believe the Maxwell stress tensor states that the force on each ...
0
votes
1
answer
83
views
What is the electric potential difference for two spheres capacitors connected in series [closed]
Consider two spherical capacitors with Identical radii for the inner and outer spheres (let them be a and b). +q and -q charges are in the inner and outer sphere on Both the capacitors. Now I connect ...
- 123
4
votes
5
answers
2k
views
Can you charge a capacitor with only voltage (without current)? If No, then how does a capacitor correct power factor?
Let me explain you why I am asking this question.
The other day I was studying about power factor correction of a (step up or any) transformer. It said that on the output side of transformer's ...
- 129
0
votes
1
answer
43
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Problem understanding the use of differentials in equation for energy stored in a capacitor
I was going through the Feynman Lecures on Physics Vol. II and arrived at section 8.1, where the equation for the energy stored in a capacitor is obtained.
We consider now the energy required to ...
- 1
1
vote
1
answer
351
views
Kirchhoff's Voltage Law does not hold for a free source RC circuit?
Say I have a simple free source RC as depicted in the image below. The capacitor initially has a charge of Q on its positive plate and at time t=0 the switch is close. I use the mesh current as shown ...
- 1,581
3
votes
1
answer
3k
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Why does a floating capacitor act differently than a grounded capacitor?
I'm having difficulty understanding why a floating capacitor will store less charge than a grounded capacitor. Imagine you have two parallel plates and a low DC voltage source like 5V, with the ...
- 35
0
votes
1
answer
794
views
Resistor and capacitor in series
If you put a resistor and a capacitor in series with a 9V battery so that the resistor is in the wire going out from the positive terminal of the battery to a plate of the capacitor.
In my opinion ...
- 323
0
votes
0
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18
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Difference between Capacitor and a battery [duplicate]
Capacitor stores electric charge and battery also stores electric charge. SO whats the difference between them?
2
votes
4
answers
34k
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Current when capacitor and resistor placed in parallel?
If the question is too long please comment to shorten it atleast , I really need an answer.
I have just started learning about RC circuits and these circuits are confusing me.My questions-1)What will ...
- 1,103
1
vote
1
answer
4k
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Why does this lightbulb glow faintly when I thouch it with my hand though it's not connected to the AC-source?
Take a look at these three pictures I made of one of our lightbulbs:
The lightbulb is placed in a fitting which can be put directly in the power socket. In the first picture the bulb is turned loose, ...
0
votes
2
answers
502
views
Confused on why energy stored in capacitor deals with moving charge from one plate to other?
According to this video, and multiple other sources, we can calculate the energy stored by a capacitor using the idea integrating the work done by moving a charge from one plate to the other at ...
- 1,177
2
votes
1
answer
1k
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Why is work done against the electric field to move charges to charge a capacitor?
I'm a bit confused as to why there is work done against the electric field when charging a capacitor, as charge is moving from high potential to low potential.
For the sake of this question, I'll ...
- 1,177
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
2
votes
5
answers
2k
views
Is voltage difference always proportional to its derivative?
We write, because of Ohm's law:
$$V=RI(t),$$
but also we have
$$C\frac{dV}{dt}=I(t).$$
From the first equation we deduce that $V\propto I$ and from the second $\dot V\propto I$. So we can conclude
$$...
- 147
22
votes
5
answers
57k
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What is the difference between a battery and a charged capacitor?
What is the difference between a battery and a charged capacitor?
I can see lot of similarities between capacitor and battery. In both these charges are separated and When not connected in a circuit ...
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