# Questions tagged [capacitance]

The ability of an object to store electric charge.

244 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
34 views

### Wouldn't extra surface area from a thicker active material layer in super capacitors be more important than minimizing the gap distance

Capacitance is proportional area, and inversely proportional to gap distance. I've read all over the internet that you need to make capacitors have as small a gap distance as possible, but I wonder if ...
129 views

### Charge density on a capacitor plate

Is charge uniformly distributed on a capacitor plate? For a conductor, charge density is more at sharp ends. So, shouldn't charge density be more on the corners of the plate?
81 views

### If you would replace ITO, would it ideally have a lower or higher relative permittivity?

ITO is used as the conductive layer in a touchscreen. If you would replace ITO in a capacitive touchscreen, would it ideally have a lower or high relative permittivity? The relative permittivity (...
132 views

### What causes resistance when moving parallel plate capacitor plates?

The electric field is perpendicular to the direction of the movement, so the vector product is zero, and thus the force should not exist. What causes it?
118 views

92 views

### How is the capacitor affected?

I know that a capacitor stores electric energy or electric charge and understand how, but I don't understand how the distance and the voltage affects its capacitance (I mean what are the mechanisms ...
193 views

### Currents in an isolated metal exposed to an alternating uniform electric field

For example, let's look at a metal sphere between a capacitor's (infinite) plates. Let's run an AC current through the capacitor, resulting in an oscillating electric field. The charges will move in ...
37 views

### Potential of 2 parallel plates

How can I write down a potential of 2 parallel plates (area $A$) with charge $+Q$, $-Q$ such that V(inf)=0 and V(in) is what I would expect, $Ed = Qd/A\epsilon_0$. Do I have to write a discontinuous ...
60 views

### Can Van Allen Radiation belts act as a capacitor?

There are two Van Allen Belts at rougly 5000Km and 17000Km from the surface of the Earth each of them containing majority of one of the charges electrons and protons). Can these belts like a ...
152 views

### Negative charge on capacitor, Kirchoff differential equation with step function

I'm solving a differential equation of the form $$200q'+\frac{200}{3}q=3U_o-6U_6+3U_{12}$$ Where $U$ is the Heaviside step function. $q(0)=0 [Coulombs]$ After solving it, I get that at time $t=18$ ...
131 views

### Energy of moving capacitor

On the following link were a discussion about energy in capacitor moving parallel to its field: Where's the energy in a boosted capacitor? My question is what happen if capacitor is moving ...
65 views

### Capacitance changes by a factor of 3 or 9?

This is an example problem with solution in a book I am reading on electrostatics. "We have two square parallel plate capacitors with length $a$ and separation $d$ with $d<<a$. If we triple ...
80 views

### Charging a spherical capacitance

How could one charge a spherical capacitor with a battery or any other emf source?
476 views

### Does the Fringe effect occur in capacitors in the interdigitated form?

I am currently doing my undergrad dissertation on graphene supercapacitors. I have read that the fringe effect is a well established phenomenon on parallel plate capacitors, but does it also occur in ...
132 views

65 views

### Energy stored in the battery of a circuit (single electron box)

Consider the following, a closed loop circuit with two different capacitors in series plus a battery that provides a voltage $V$ (in series with the capacitors). You may add a resistance if that helps....
236 views

### Discharging a LC(R) Circuit

Reading through my lecure script I encountered this example which I don't quite understand: Given is the following Circuit: At time $t= 0$ the circuit is closed, before that the circuit was open, ...
338 views

### Electric energy density

The electric energy density for a parallel plate capacitor is $\frac{1}{2}\varepsilon E^2$ where $\varepsilon$ is the dielectric constant and E is the magnitude of electric field. In my textbook it ...
628 views

### dielectric slab inserted into constant charge capacitor

I derived the equation for the force $F$ acting on a dielectric of dielectric constant $K$ being inserted into a constant voltage (connected to battery) parallel plate capacitor of capacity $C$, ...
425 views

### Gauss Law use in an example question

In the textbook (Modern Physics for Scientists and Engineers by Douglas Giancoli) it asks for a capacitance calculation. However, I want just the explanation of the electric field calculation between ...
491 views

### What book will help me understand Electric Circuits?

I have a problem having a clear picture when it comes to solving electrical circuits. I am talking about complex circuits which contain Inductors and capacitors . The methods introduced are clear to ...
220 views

### Connecting spheres of different capacitance

If I connect a sphere of capacitance $C_1$ to a charged sphere of capacitance $C_2$, will the charge be distributed evenly on both spheres (is the charge density going to be equal on both spheres?). ...
2k views

### No change in voltage in a capacitor

While trying to solve this question: Photo copy of the question and answer: Question:On charging a parallel plate capacitor to potential V the spacing between the plates is halved and a dielectric ...
96 views

### How to simplify such structures to calculate equivalent capacitance?

I am self studying electrostatics for competetive examinations but there is this series of questions demanding equivalent capacitance and I direly need a intuitive understanding of these situations.
850 views

### What happens in the RC circuit when being charged?

Say I have this RC circuit and at the start, the switch is off (current going from left to right and the starting point is just above the battery). I understand that then the capacitor acts just like ...