Questions tagged [capacitance]

The ability of an object to store electric charge.

188 questions
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In series RLC circuit, does decreasing the capacitance value really make the circuit more capacitive circuit?

This seems very counter intuitive to me. How can decreasing the capacitance value make the circuit more capacitive ? The math tells me so : If $C$ decreases then $X_c = \dfrac{1}{\omega C}$ ...
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What is Capacitance for a Spherical Shell pair?

Consider three Scenarios : 1) In this case , we are Calculating $$\frac{d(Q_b)}{d( \triangle Vab)}$$ 2) In this case , we are Calculating $$\frac{d(Q_a)}{d( \triangle Vab)}$$ 3) In this ...
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Capacitance of octant of a sphere

What's the capacitance of octant of a sphere if the capacitance of sphere is C? I think that some combination of octants should make the capacitance of the whole. But what combination will it be ...
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Inductance and Capacitance of wire near ground plane

I'm stuck on the following question and would greatly appreciate any help: A lossless transmission line is formed by a wire of radius a placed in vacuum a distance d above an infinite conducting ...
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Potential energy on a spherical capacitor

I have been having some trouble understanding the storage of energy inside a spherical capacitor composed of two concentric spherical shells where the inside shell has radius $a$ and charge $2q$, ...
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Designing capacitor or resistor systems where capacitor or resistor can bear limited voltage

A capacitance of $2\ \mu F$ is required in an electrical circuit across a potential difference of $1.0\ kV$. A large number of $1\ \mu F$ capacitors are available which can withstand a potential ...
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LC circuit problem

I am currently working on a LC circuit problem where there were given this question that I couldn't understand which is : theoretically justify the shape of the curve (the spring curve) by ...
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Is there a theoretical limit for the Dielectric Constant

If we're being pedantic, it's a Dielectric Tensor, and I know that it changes with both temperature and frequency, but the question remains... How would one calculate the theoretical maximum ...
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How conductive must be capacitor plates?

So from equations I see that a capacitors capacitance increases with area of conductive plates and dielectrical value of dielectric between the plates. It also increases with decrease of distance ...
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Safety in ultracapacitor discharge regarding possible effects of induced voltages

Problem I am trying to analyze the safety of two experiments involving ultracapacitor short-circuit discharges. In the first experiment one has a discharge of a $0.45 \,\mathrm{F}$ capacitor with ...
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The effect of the value of capacitance in relation to the load resistance of a single capacitor in smoothing

I can't find a good explanation about: The effect of the value of capacitance in relation to the load resistance of a single capacitor in smoothing. I think it has to do with the following formula:...
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Which Direction does current flow?

Summary: To simplify, I made the voltage equal to difference in charge: V = Q1 - Q2. If you stack the voltage, current should flow counter-clockwise If you look at the individual charges, current ...
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How does a super capacitor supply extra energy to an external circuit if the electrolyte doesn't go anywhere

In a super capacitor there is a double layer effect due to charged ions moving into layers. But unlike the electrons in conventional capacitors which line up on a conductive plate and are free to move ...
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Regarding the zero internal electric field in a conductor (electrostatic case)

Let's say we have a homogenous electric field in the $z$-direction. For computational simplicity let's say we have a thin sheet of metal covering entire the $x$-$y$ plane. The answer here is straight ...
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Circuit with capacitor and battery- why same voltage?

If we connect a capacitor and a battery in the same circuit, what makes the charge move until the voltage on the capacitor is the same as voltage on battery?
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I'm learning electromagnetism from Purcell's book. He say that if we have the following circuit: $$-\frac QC + RI = \mathcal E_0\cos\omega t~,\quad I = -\frac{\mathrm dQ}{\mathrm dt}$$ The ...
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Where will the charge be stored in this capacitor?

A capacitor whose charged plate is hemispherical,concave side is facing each other then will the charge be stored on concave surface like all other capacitors(i.e. parallel plate,cylindrical etc.) or ...
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Finding Inductance in an AC RLC Circuit?

In the laboratory you find an inductor of unknown inductance $L$ and unknown internal resistance $R$. Using a dc ohmmeter, an ac voltmeter of high impedance, a 1 microfarad capacitor, and a 1000 Hz ...
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Effect of potential difference on capacitance

I've read multiple threads here discussing the relation between capacitance and potential difference and they have begun to confuse me. I have a homework question about which of the following will ...
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LCR circuit at resonance

I am studying about the LCR circuit and have a question regarding potential difference across inductor and capacitor. From the thing I have studied I came to know about that potential across inductor ...
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Physics of the capacitance of an electrolytic capacitor

In explanations about the electrolytic capacitor one often cites the formula $$C = \epsilon_r \epsilon_0 \frac{A}{d}$$ for the capacitance $C$. Then one says that by enlarging the area $A$ via ...
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What are the first couple terms of the Taylor series for the evolution of this network of capacitors and resistors?

note: This is a computational problem, and I only need approximate accuracy, so the overall goal is, for a given accuracy and $\Delta t$ to compute the state of the system at $t+\Delta t$ to within ...
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Why do we change signs arbitrarily while calculating RC circuits formulas?

When I have to calculate the formulas regarding RC circuits, for example the process of charging a capacitor, there is a discrepancy between my calculations and those of all the books I can find. Let'...
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capacitance of cube skeleton

A cube of 12 capacitors is very common problem. find capaciance accross edges we get 12c/7. But lets say we have 8 more capacitors involved now. that is we have capacitors at all sides of cube and ...
Consider the following derivation: (Source: http://www.ncert.nic.in/html/learning_basket/electricity/electricity/electrostatics/inner_sphere.htm) If a charge of $+Q$ coulombs is given to the outer ...