All Questions
26
questions
2
votes
0
answers
42
views
What if two plates charged with different charges are placed face to face?
I'm asking this question because I can't solve it even if I ask a lot of smart people. (Please understand that I don't speak smoothly because I use a translator. I'm korean student..)
In the next ...
- 21
1
vote
0
answers
105
views
Capacitance of a System of Two Spheres
To explain more clearly, I am looking for how one would derive an expression for the capacitance of a system which consists of two conducting spheres of radius $a$ separated by a distance $d>2a$. I ...
- 11
-1
votes
1
answer
75
views
What is electric permitivitty?
I have read 10 different explanations for this in 10 minutes. By definition, to permit means to allow something, but some sites say that it is actually how much a material resists the electric field?
...
- 183
0
votes
0
answers
36
views
Are Idealized Transformers Realizable?
Since parasitic capacitance in an inductor is always in parallel with its inductance, would this effectively become analogous to magnetic remanence exhibited within rebars (made from carbon steel) ...
- 1
1
vote
2
answers
128
views
Is the work done in separating electron from neutral atom stored in its electric field?
This particular thought crossed my mind while deriving the expression for energy density of electric field in parallel plate capacitor.
Energy density= $\frac12 \epsilon E^2$
It appears to me that ...
- 1,568
1
vote
1
answer
88
views
Capacitance of ferroelectric capacitor in saturated regime
Consider a ferroelectric plate capacitor connected to an AC source in the presence of a strong static external electric field which sets the ferroelectric medium in the saturated regime.
The question:
...
- 1,149
0
votes
1
answer
42
views
Capacitors and voltage rating
Imagine a battery that creates a +9000V Potential difference in respect to ground (The Earth) in it's positive terminal. (The Earth is at 0V in this example)
And a +8992V potential difference in ...
- 323
0
votes
1
answer
391
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 ...
- 175
1
vote
1
answer
4k
views
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, ...
-1
votes
1
answer
908
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 $C$, ...
- 21
2
votes
0
answers
142
views
Why do ceramic magnets work on touch screens?
I know how our touch screens work by sensing changes in voltage with capacitors, and then pinpointing our fingers location. But recently I was playing with a ceramic magnet on my phone.
As I took ...
2
votes
1
answer
1k
views
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
0
votes
1
answer
248
views
How to derive and write Kirchoff loop law for circuits including capacitors?
Consider a circuit like the one in the picture
Where $V_0$ is an electromotive force.
How do I write Kirchoff "loop law" for circuits like the one in picture (i.e. with capacitors)?
Here is the ...
- 2,617
0
votes
1
answer
3k
views
EMF in capacitor circuits
In the right circuit in the attached picture, I am given a rectangular loop of wire which is situated so that one end (height $h$) is between the plates of a parallel-plate capacitor, oriented ...
- 1,023
1
vote
1
answer
81
views
Are there losses in AC when passing through a capacitor?
A capacitor allows AC to pass through. From what I've read it's caused by the changing electric field in the space between the capacitor plates which causes a change in charge on the other plate of ...
- 1,043