The capacitance tag has no wiki summary.
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2answers
46 views
Equivalent RC circuit to a RRC circuit?
I'm in doubt about a situation that I've seen sometimes: imagine we have a resistor in parallel with a resistor and a capacitor in series. Since I don't know how to generate figures of circuits to ...
1
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1answer
26 views
Capacitance of a conducting disk
I'm reading this(PDF) derivation of the capacitance of a thin conducting disk. The surface charge density of such a disk can be shown to be:
$\sigma(r) = \frac{Q}{4\pi a\sqrt{a^2 - r^2}}$ (in ...
0
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0answers
36 views
Work required to pull capacitor plates apart when connected to battery [closed]
For (a), I just use $F = k \frac{Q_1 Q_2}{r^2}$, then (b) $W = - \Delta U = - qE \Delta d$, correct so far? But how do I do (c)?
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3answers
82 views
Capacitor Charging and Discharging when connected to the ground
When we charge a capacitor using a battery and then remove the battery, the plates of capacitor becomes charged. One holds positive charge and the other one gets equal negative charge. o. k. ?
Now ...
0
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0answers
57 views
Capacitors discharging in series [duplicate]
If you connect positive plate of a charged capacitor to ground, it doesn't get discharged. Now consider $4$ capacitors of equal capacitance connected in series to a $10\, \mathrm{V}$ battery. Connect ...
2
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1answer
61 views
How we approach RLC circult from RLGC model?
In the text, it introduces a practical model to investigate a transmission line (like BNC cable), it considers the transmission line has resistive $R$, inductance $L$, conductance $G$ and capacitance ...
1
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1answer
27 views
Finding the Steady State Charges
Here the problem states to find the steady state charges on the condensers.
But here the capacitor have a resistance in parallel connection , so how can we distribute the potential drop across ...
0
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0answers
29 views
Experiments related to Capacitor and Prism [closed]
I want my students to learn experiments on prism and capacitor. Can you provide me different experiments related to prism and capacitor (except charging and discharging). The experiments will be given ...
0
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1answer
20 views
Work due to introducing a dieletric in a capacitor
I have a doubt about a couple of exercises tha asks to find the work done on introducing a dieletric between the plates of a capacitor. Yes, this question is in the general case, how do we procede? I ...
0
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2answers
61 views
Inserting metal into parallel plate capacitor
The plates of an isolated parallel plate capacitor with a
capacitance C carry a charge Q. The plate separation is d.
Initially, the space between the plates contains only air.
Then, an ...
1
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2answers
69 views
Flashlights and Capacitors
Why capacitors are used in flashlights of cameras instead of attaching the light directly to the battery? How this leads more light?
5
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4answers
200 views
Energy Gain with capacitor?
I have a question about energy gain in capacitors. Assume the following system:
As the electron gets accelerated inside the capacitor, it will have more kinetic energy coming out than going in. But ...
0
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2answers
60 views
Why does the area of the plates affect the capacitance?
Why does the area of the plates affect the capacitance? Lets say I have a parallel plate capacitor with a charge of 10C and a potential difference of 5V. By the definition $C=Q/V$, the capacitance is ...
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0answers
17 views
What is the principle of active voltage balancing/equalizing device?
I am wondering about active voltage sharing devices. Their purpose is to equally divide voltages on slightly unequal super-capacitors. I found some papers like this, but it is too scientific.
I want ...
0
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1answer
48 views
Where are exactly the charges of charged capacitor?
a capacitor is connected to a battery and is charged, are there charges inside the wires or they just accumulate on the surfaces of capacitor?
0
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0answers
28 views
The heat dissipated in the resistance in a C-R circuit [closed]
If an uncharged capacitor (of capacitance $C$) is charged by connecting it with an ideal battery and a resistance R (The capacitor and resistor are in series combination ), then the heat generated in ...
0
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0answers
35 views
Can you find the potential between capacitor plates with liquid dielectric in the capacitor's frame? [closed]
A magnetic field B is applied perpendicular to the plates of a capacitor whose parallel plates are separated by d. An electrically neutral liquid of relative dielectric constant k flows between the ...
0
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0answers
50 views
Energy lost when charging a capacitor: where does it go? [duplicate]
I've been wondering for a while where half the energy goes when charging a capacitor... Most textbooks say that it is dissipated through resistance in the wires, but what happens if, say, the wires ...
0
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2answers
260 views
Capacitors and resistor in series and in parallel [closed]
In this circuit, are $R_1$ and $C_1$ in parallel and $C_2$ and $R_2$ in series?
I have think that the currents that flows trought $R_1$ isn't the same that flows trought $C_1$ so, $R_1$ and $C_1$ ...
0
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2answers
60 views
Why isn't this capacitor charging?
Let's say you have a parallel plate capacitor and you connect one plate to the positive terminal of a battery and the other plate to the negative end. So this is like a static situation, you have a ...
1
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3answers
134 views
Can I charge a capacitor using 2 batteries?
1 capacitor, 2 separate batteries (Battery A and Battery B).
Connect A+ to one side of the capacitor and B- to the other side of the capacitor.
A and B are not connected, there is no closed circuit.
...
0
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0answers
122 views
Energy stored in charge capacitor [closed]
Two identical parallel-plate capacitors, each with capacitance $C$, are charged to potential difference $V$ and connected in parallel. Then the plate separation in one of the capacitors is doubled.
...
2
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2answers
135 views
Why does a capacitor discharge?
Suppose a charged capacitor (parallel plates), the negative and positive charges on two plates attract each other. Which force cause the negative charge carriers (electrons) move through the circuit ...
1
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1answer
103 views
Calculate Capacitance in Series AC Circuits?
I'm supposed to calculate the capacitance of an unknown capacitor in series, but I'm not sure exactly which equation to use.
I know the voltage across the resistor (Vr), voltage across the capacitor ...
1
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1answer
140 views
Parallel capacitors without battery. Does charge flowing after a dielectric input?
If I charge two capacitors which are connected parallel $[$the minus (-) of the one opposite to the minus (-) of the other and the plus(+) of the one opposite to the plus (+) of the other.$]$, will I ...
0
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1answer
226 views
Non conducting charged planes
I have two parallel non conducting charged planes with opposite charges $6\mu C/m^2$, area $A = 3m^2$ and distance between the planes $d = 0.004 m$. I know the potential between these two planes is ...
2
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1answer
78 views
Two capacitors sharing charge
My two capacitors:
I have these two capacitors ($C_1 = 3\mu F, C_2 = 4\mu F$) both initially under 19 volts. Then, I added a dielectric with $k=4$ at $C_1$ and entire ...
1
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1answer
43 views
What happens to this energy of the capacitor?
Let's say you have a charged, isolated parallel plate capacitor with a certain voltage. My book says that if you insert a dielectric, the voltage drops. However, that would require the energy between ...
2
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4answers
104 views
Capacitance of a capacitor
Why does the capacitance of a capacitor increase if the distance between the two plates of a parallel plate capacitor is decreased? I think, with decreasing distance between the two plates, the force ...
0
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1answer
61 views
Capacitor and hydraulic analogy
Would anyone kindly explain me the hydraulic analogy for the working of a capacitor w.r.t the article of wikipedia http://en.wikipedia.org/wiki/Capacitor... Help!!
3
votes
1answer
152 views
What do physical properties of materials trigger the capacitive touch screen?
I have watched some youtube videos about capacitive touch screen
http://www.youtube.com/watch?v=ZHzaVzYEZbw
http://www.youtube.com/watch?v=GmCE18RMEeQ
The videos show that a conductor(finger), in ...
3
votes
2answers
406 views
Capacitor circuits with light bulb
Let's say we have a normal circuit with a light bulb, with wires and a battery.
When one places a capacitor in this circuit, how is the light bulb able to light up, even when the capacitor prevents ...
4
votes
2answers
471 views
What happens to capacitor’s charge when the plates are moved further apart?
In my physics textbook there is an example of using capacitor switches in computer keyboard:
Pressing the key pushes two capacitor plates closer together, increasing their capacitance. A larger ...
3
votes
1answer
83 views
How would I explain a farad being a second per ohm?
The farad has many alternative representations in SI. I can comprehend some of them. For example, a capacitance of 1 farad means that it will take a single coulomb to create a single volt between the ...
1
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1answer
63 views
Why does the presence of a battery change whether a circuit is in parallel or series?
If I take a closed circuit with two capacitors and a voltage difference, the circuit is apparently in parallel, but if I introduce a battery, the circuit is in series. Why does the presence of the ...
8
votes
3answers
322 views
Where's the energy in a boosted capacitor?
Suppose I look at a parallel plate capacitor in its rest frame and calculate the electrostatic energy, $E$.
Next, I look at the same capacitor in a primed frame boosted in the direction perpendicular ...
0
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2answers
417 views
How does the voltage between two charged sheets change if change their distance
Suppose I have two charged capacitor plates that both are isolated and carry a charge density $D = \frac QA$. According to textbook physics the electric field between them is given by $E=\frac D ...
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2answers
95 views
How can you calculate (or convert) the Wh of a capacitor whose energy is given in Farads
When trying to compare the energy in a battery to the energy in a capacitor, the units don't match up. How can one compare a battery whose Ah are 10 and Voltage is 3 (for a total of 30 Wh) to a ...
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2answers
158 views
What's the difference between Capacitors, Ultra-Capacitors and Batteries
Capacitors are known to hold and release energy very quickly, unlike the slower release that batteries exhibit. If one were to bunch many (1000's of) capacitors together could they function as a ...
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0answers
19 views
How are current and voltage out of phase in capacitive circuit? [duplicate]
Possible Duplicate:
Physical explanation for capacitive circuit
We say that in capacitive circuit, the voltage and current are out of phase. Current is 90 (degrees) ahead of voltage. What ...
1
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1answer
72 views
Magnetic force on capacitor
I have this problem: I have a capacitor formed by two parallel square-shaped plates, of side $a$, and with distance $d$ between them. They're asking me out of other things, the magnetic force as a ...
0
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1answer
89 views
Is it possible to charge a capacitor to any potential? Does it depend on the dielectric placed between them?
Is it possible to charge a capacitor to any potential? Does it depend on the dielectric placed between them? Or, are there other factors affecting it?
5
votes
1answer
524 views
What defines the maximum charge a capacitor can store?
The formula for a capacitor discharging is $Q=Q_0e^{-\frac{t}{RC}}$
Where $Q_0$ is the maximum charge. But what property defines the maximum charge a capacitor can store?
If it depends on ...
3
votes
1answer
445 views
What is the role of battery across a Parallel plate capacitor having equal charge?
Each plate of a parallel plate capacitor has a charge $q$ on it. The capacitor is now connected to a battery. Now, which of the following options are correct?
a) The facing surfaces of the ...
0
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0answers
58 views
Explanation of NMOS processes
So, gate (poly-si + $SiO_2$) and $p^{-}$ silicon operate as capacitator.
But how are voltages and charges are applied? In order for inversion to occur, there should be charges formed in poly-Si, ...
0
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1answer
258 views
Capacitance per unit area and CMOS case
In a modern 0.35μm CMOS processor, the gate oxide thickness is around 80Å = 8nm. This gives us a capacitance per unit area of $430nF/cm^2$
I am not getting how one gets this capacitance per unit ...
0
votes
1answer
538 views
Capacitor charging and discharging
I have a conceptual question.
The circuit is shown below. Let us assume that the capacitor shown in the figure is of 2.2 micro-farads having rated level of 5 volts and we decide to charge it up to 2 ...
2
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1answer
190 views
Why does a capacitor discharge a percentage of the original energy in the same time?
If I charge a capacitor ($220\mu{F}$) using a 6V battery, and then measure the time it takes to discharge 90% of the initial energy over a resistor (${100k}\Omega$), and then charge the same capacitor ...
0
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1answer
118 views
Physical explanation for capacitive circuit
In capacitive circuit, the voltage and current are out of phase. the current leads the voltage by 90 degrees. this can be explained by these two equations:
$$V = V_{\max} \sin \omega t$$
$$I = ...
0
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1answer
48 views
Charging using a CRT TV set
I was doing an experiment with my CRT TV where I put aluminum foil on the screen wire it to a can and open the TV and a ring between 2 can will swing if I ground the other can. ...
