Questions tagged [capacitance]
The ability of an object to store electric charge.
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1answer
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Capacitance and it's intuitive explanation
I was looking for an intuitive explanation for the capacitance between two plates, couldn't find any suitable though. So I tried to figure it out myself and I am wondering if it is correct.
...
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1answer
16 views
Polarized Vs Non-Polarized Capacitors
I am wondering what makes a polarized capacitor physically different than a non-polarized capacitor. I am aware they are functionally different.
I understand the physics of a non-polarized capacitor, ...
-1
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2answers
62 views
RC circuit series and parallel [on hold]
R and 2R are in parallel.
4R and 3R are in parallel.
I dont know where to go after calculating the the parallel Rs.
Do you become in series? If so, how?
It is right after the switch is closed. So ...
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0answers
28 views
Series LC circuit capacitive frequency control [on hold]
if I had a series LC circuit with an air core inductor and a varyable capacitor (whose capacitance can be varied by a large margin) could I in theory be able to drive my resonator across a wide range ...
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0answers
20 views
Capacitance of two parallel cylinders of finite length
I've got some big troubles calculating the capacitance of two parallel cylinders of finite length.
If the cylinders are infinite everything is fine but I need an excat solution or at least a good ...
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1answer
22 views
How can a charged hollow sphere induce charge on a neutral conducting sphere kept inside it?
In case of a charged conducting hollow sphere charge resides on the surface and the field is radially outwards or inwards depending on the charge.Due to the symmetric consideration field inside the ...
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6answers
75 views
Telling if Capacitors are in Parallel or Series
So C1 and C2 are in series. But if each one is placed in red boxes, they are in parallel?
It's confusing going jumping between current, capacitors, and resistance.
For me it's kinda confusing ...
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0answers
18 views
Motion of dielectric inserted between plates of parallel plate capacitor [closed]
If a dielectric is inserted between the plates of a parallel plate capacitor a force will act on it, so will it oscillate or not?
Two cases would be considered:
1: battery not connected
2: battery ...
2
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4answers
94 views
Internal resistance and Instantaneous current?
Okay, this would probably seem a pretty basic doubt but I can't understand this thing. I know that when the current is not flowing in the battery the voltage across the terminals is the emf of the ...
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1answer
24 views
Question on capacitance between two parallel cylinders
We are asked to prove that the capacitance of two infinitely long
uniformly charged conductors with coaxial cylindrical surfaces is given by
\begin{equation}
C= \dfrac{2\pi\epsilon_0L}{\mathrm{ln}\...
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0answers
25 views
What is the Potential difference in $C_1$? [duplicate]
I can not seem to figure this out. My try so far:
put C2 and C4 as C' by parallel
put C' and C1 as C'' by series
Finally, Put C'' and C3 and C5 as Ct by series
find Qt by Qt=Ct*V
after finding the ...
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1answer
15 views
Electric field in capacitor arrangement with different dielectric media
Please consider the following arrangement of infinitely extended charged plates. In z-direction the system also extends to infinity. The charged plate in the middle of the figure is 2x negatively ...
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2answers
23 views
What is it that drives the electrons from one plate to another through a battery in a capacitor?
The situation is as follows:
You have a parallel plate capacitor, disconnected from a battery on both ends.
We know the battery tries to maintain a constant potential difference between its two ends. ...
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4answers
57 views
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 ...
2
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0answers
85 views
A pendulum connected to a capacitor [closed]
A mathematical pendulum of length L whose rod is made of a conducting material
moves so that its inferior end slides without friction on a metallic support in
the shape of an arc of circle. The rod ...
1
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1answer
31 views
Charges on conductor
So i was reading an answer to question Why are the two outer charge densities on a system of parallel charged plates identical?
Points that I didn't understand
that how come -Q1+x charge can get ...
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0answers
26 views
Connecting one lead of capacitor to a certain charged object (to get a potential difference)
Setup-A charged sphere , connected to one plate of capacitor , other lead of capacitor is free. Question-Will the capacitor plates go through a charge redistribution ? Arguments/Counterarguments-I ...
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3answers
72 views
Is a complete circuit required for capacitors to redistribute charges?
Suppose I have two capacitors of different capacitance $C_1$, $C_2$and they have been charged prior connecting by voltage of $V_1$ and $V_2$ respectively the positive plate of one capacitor is ...
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2answers
50 views
How do we extract energy from capacitors?
I have an intuitive reasoning for the use of capacitors. I think that it is used to store electrical energy.
Without going in much detail in engineering and being at an introductory level of ...
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0answers
29 views
How to use energy conservation in following case [duplicate]
A capacitor of capacitance C is intially uncharged is connected with a battery of emf ε.Find the heat dissipated in the circuit during charging?How can we apply energy conservation although there are ...
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0answers
17 views
Is the potential difference across any capacitor equal for n identical capacitors connected in series? [duplicate]
(https://i.stack.imgur.com/Pfit8.jpg) Is the potential difference equal for n identical capacitors connected in series? Please go through the image as my confusion lies there.
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1answer
31 views
How does the stud finder work?
My textbook explains how a type of stud finder works by an illustration. What I can’t understand is how does the piece of wood have an effect on the capacitance of the plates when it is so far away ...
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2answers
48 views
Impedance of an LCR circuit
So I am trying to understand how to find the impedance of the parallel LC component of this filter circuit. I am given that the transfer function $\mathbf{T}_C = \dfrac{\mathbf{V}_{out}}{\mathbf{V}_{...
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3answers
56 views
Why is the force required to keep a parallel plate capacitor EQ/2?
In our electrostatics course we were talking about how if you increase the separation of the plates by a tiny amount, then as the field is still constant, the potential difference increases. This ...
7
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4answers
1k views
Why is there no current between two capacitors connected in series?
I want to ask a question about the figure below.
Why the current does not flow from $-Q$ term to $+Q$ term or from a to b since there is a voltage?
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2answers
66 views
Does Kirchhoff's rule break down as it applies to capacitors
A homework problem asked me to find the voltage across a series of capacitors after they came to equilibrium.
Essentially a capacitor C1 with a capacitance of 6.0 F is charged until the potential ...
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5answers
83 views
If current through a resistor is zero, does the circuit break?
I'm really confused. I'm studying about how capacitors are charged, and I learnt that there's a resistor attached in series with the capacitor when it is being charged. When the capacitor is fully ...
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3answers
64 views
Charging capacitor in an incomplete circuit [closed]
I have 2 confused questions regarding the below circuit. please help me out
How will the capacitor even charge in the following scenario when the right side of the capacitor is not connected to ...
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1answer
29 views
Conduction current for parallel-plate capacitor
I am reading Sadiku's Elements of Electromagnetics and here is the proof given to show that conduction current = displacement current for parallel-plate capacitor.
Displacement current:
\begin{align*}...
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vote
1answer
23 views
Repulsive force from charge accumulation in a capacitor plate?
During a charged state of a capacitor (Regardless of the type of capacitor),
Simple parallel plate:
.png
Parallel plate with dielectric material in the gap:
]3
Supercapacitor:
How is the ...
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votes
1answer
22 views
Is it possible to create and control a magnetic field in a dielectric material?
A capacitor is usually formed by an insulater between two conductive plates. By applying voltage difference between the plates we create an electric field within the insulator in one direction. If you ...
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1answer
40 views
Electric potential and voltage
A capacitor is connected to a battery with constant voltage. If you approach one of the plate to the other, what happens to electric potential?
I already have an answer to this question but it's ...
1
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0answers
37 views
Calculating the self capacitance of a rectangular electrode with a dielectric on one side
I am trying to derive an expression for the capacitance of a rectangular electrode with a dielectric material of thickness $t$ and relative permittivity $\epsilon_r$ in contact with one side, sized ...
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1answer
46 views
Neglecting capacitor from circuit
Take a look at this circuit :
This question is answered in $Serway$ $7th$ ,And the book neglected 8 Farad capacitor because the voltage between $c$ and $d$ is zero.
My questions is :
$1.$Should not ...
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1answer
26 views
How can we analyze electronic capacitors in series? [closed]
Two capacitors are in series, such as in this circuit diagram:
When doing a circuit analysis, how can we describe the voltages and charges across the two capacitors?
1
vote
1answer
67 views
Does the voltage of the battery change if you use it? [closed]
If you use the battery to charge a capacitor does the voltage of the battery decrease or still the same? Does the voltage of a capacitor decrease if you use it to charge another capacitor?
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1answer
42 views
Redrawing circuit rules
Take a look at this circuit:
Is it allowable to redraw the circuit like this ? Can I move cd wire until it merge with b junction ? Can I move e point like what I did in the figure ?If yes why this ...
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1answer
44 views
How to solve these kind of electric circuit? [duplicate]
This question from Physics For Scientists And Engineers 7th page 746.
After redrawing , Actually I cant see any two clear capacitors that we can be combined , First we cant combine $C$1 with $C$2 ...
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1answer
23 views
How is current affected by a charging capacitor in parallel to a resistor?
Imagine a circuit with a battery followed by a lightbulb and an uncharged capacitor in parallel. Next to it is an open switch. When I close the switch completing the circuit, does the brightness of ...
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0answers
19 views
Regarding induced magnetic field due to changing electric field
I am trying to solve this question:
My approach was to first notice that the electric field is decreasing, therefore the change in electric field is to the left. If I point my thumb in the direction ...
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0answers
12 views
Effects generated from a supercapacitor placed in a time varying external magnetic field?
The diagram above, showcases the simple outlook of a supercapacitor's interior and combining it with a full circuit loop.
If an exterior magnetic field is introduced in all the operating states of a ...
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1answer
51 views
Calculating the potential difference of a capacitor [closed]
As far as I know the voltage between the plates of a capacitor will be reduced due to discharging. I wonder how much the voltage would be changed if the capacitor lost %25 of its stored energy.
...
2
votes
2answers
89 views
Parasitic capacitance in real resistors
Typically, I'd assume (A) is only a justifiable answer when the two metal end caps have essentially infinite area, or when the spacing between end caps is far smaller than their respective areas, in ...
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1answer
43 views
My fingers are sparking large source of electricity when I touch plastic boards covered with polythene
Still I don't understand why am getting such voltage & it's the same feel that I touched 250 voltage of current. Also when I put two fingers on opposite direction (when I am removing polythene ...
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0answers
24 views
$j$-$\omega$ method alternating current circuit help [closed]
I'm suppose to calculate the current and the phase angle. Can someone please tell me if this is the correct solution?
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1answer
34 views
CombinationsDielectrics in parallel
I was reading about dielectrics and wondered why there was no formula for their parallel connection between two parallel plate capacitors. So I thought of deriving it myself.
Let $k_1$ and $k_2$ be ...
0
votes
4answers
39 views
Finding the charge on a capacitor (RC circuit)
I am having trouble finding the charge on the capacitor for $t\rightarrow \infty$ after the switch has been closed at $t=0$. I already know the current $I$. I also have to find out on which sides the ...
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2answers
52 views
How Do I Calculate the Potential of System?
I was doing my homework when I came across this question:
Three equal point charges, each with charge $1.40 \, \rm\mu C$ , are placed at the vertices of an equilateral triangle whose sides are of ...
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2answers
53 views
Railgun design, which is preferred, voltage or farads?
I am building a rail gun for a physics project, but I am confused on whether to use capacitors like 2.7V 500F capacitors or a 400V 3300uF capacitor. Most tutorials seem to use many 400V ones in ...
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0answers
41 views
Proper utilization of Ampere’s Law
I am tasked with finding the magnetic field due to a bus bar, which seems to have the exact same set up as Problem 7.62 in the fourth edition of Griffiths' textbook on Electrodynamics.
To which I ...
