What is Parallel plate capacitor: Definition and 190 Discussions
A capacitor is a device that stores electrical energy in an electric field. It is a passive electronic component with two terminals.
The effect of a capacitor is known as capacitance. While some capacitance exists between any two electrical conductors in proximity in a circuit, a capacitor is a component designed to add capacitance to a circuit. The capacitor was originally known as a condenser or condensator. This name and its cognates are still widely used in many languages, but rarely in English, one notable exception being condenser microphones, also called capacitor microphones.
The physical form and construction of practical capacitors vary widely and many types of capacitor are in common use. Most capacitors contain at least two electrical conductors often in the form of metallic plates or surfaces separated by a dielectric medium. A conductor may be a foil, thin film, sintered bead of metal, or an electrolyte. The nonconducting dielectric acts to increase the capacitor's charge capacity. Materials commonly used as dielectrics include glass, ceramic, plastic film, paper, mica, air, and oxide layers. Capacitors are widely used as parts of electrical circuits in many common electrical devices. Unlike a resistor, an ideal capacitor does not dissipate energy, although real-life capacitors do dissipate a small amount (see Non-ideal behavior). When an electric potential (a voltage) is applied across the terminals of a capacitor, for example when a capacitor is connected across a battery, an electric field develops across the dielectric, causing a net positive charge to collect on one plate and net negative charge to collect on the other plate. No current actually flows through the dielectric. However, there is a flow of charge through the source circuit. If the condition is maintained sufficiently long, the current through the source circuit ceases. If a time-varying voltage is applied across the leads of the capacitor, the source experiences an ongoing current due to the charging and discharging cycles of the capacitor.
The earliest forms of capacitors were created in the 1740s, when European experimenters discovered that electric charge could be stored in water-filled glass jars that came to be known as Leyden jars. Today, capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass. In analog filter networks, they smooth the output of power supplies. In resonant circuits they tune radios to particular frequencies. In electric power transmission systems, they stabilize voltage and power flow. The property of energy storage in capacitors was exploited as dynamic memory in early digital computers, and still is in modern DRAM.
It is known that the energy required to charge a parallel plate capacitor (thickness ##x##, surface area ##S##) with a dielectric (with dielectric constant ##\epsilon##) is
$$E=\frac{xQ^2}{2S\epsilon\epsilon_0}.$$
I would think that the work done goes only into the electrostatic energy between...
a) if I take a Gaussian cylindrical surface whose circular area are present in the meat of the two plates of the capacitor, then the electric flux through this Gaussian surface is zero ( as the electric field inside the meatof the capacitor is zero and between the capacitors, electric field is...
Because of the plate P, the capacitor becomes a piece of conductor. It contains zero net charge and has 0 potential difference. Hence, the capacitance is ## \frac 0 0 # # that is undefined.
The capacitance of a capacitor is defined as its capacity to store charge when a potential difference is...
Before I can find the force on q I must balance the charges. This problem starts of with -q and q inside the capacitor. I have added image charges on the opposite side of each plate. Would this work?
I use the following equations to understand this question/answer.
First, C = k(ε*Area)/distance = Q/V = Q/ (E*distance)
As a slab of glass is added, k increases and thus E decreases.
F=QE, as E decreases, force decreases as well. How does this relate to the 'force attracts the glass into the...
Does anyone have a reference or solution for a parallel plate capacitor in the Rindler metric? I'm particularly interested in the case where the capacitor plates are in the xz or yz planes, z being the direction of the acceleration.
The motivation is to get an idea how a transmission line...
Summary:: Griffiths problem 8.5
Problem 8.5 of Griffiths (in attachment)
I already solved part (a), and found the momentum in the fields to be $$\textbf{p}=Ad\mu_0 \sigma^2 v \hat{\textbf{y}}$$
In part (b), I am asked to find the total impulse imparted on the plates if the top plate starts...
This is the problem I'm working on. So far I know:
1. I am assuming the free charge density is +sigma for the top plate and -sigma for the bottom plate.
2. The electric field from the plates goes from top to bottom plate, in the negative z direction.
3. The electric field of the capacitors...
The question is partially taken from Griffith's book. I am confused about the physical meaning of momentum in fields. I have determined the solution and found that in part d the momentum crossing the x-y plane is some value in the positive z direction. I don't however understand the physical...
Hello,
A question came up in my head that I couldn't think of a way to math out.
Say I want to design a parallel plate capacitor. The equation for capacitance is quite simple:
Everything in this equation makes sense, besides for the distance. This is saying that an infinitely small length...
I've been given this question for my TMA2, I've tried looking at the learning material but it gives no information on how to calculate the gap? Does anyone have a formula for this? Or can someone point me in the right direction?
Thanks
Hello,
I have a question regarding the capacitor/resistor network as shown.
My question is simple. I realize that the instant the switch is closed, then the top plate of the capacitor must be at a potential (VA) of 5v.
However, I also realize that the instant the switch is closed, literally...
A while back I thought of an issue with parallel charged plates. Imagine this: a set of opposite charged resistive plates with holes in the center. In theory, there is a finite amount of energy required to push a positive charged particle through the hole in the positive plate (in theory it...
Hi!
Could you please help me with the queries below? Thanks a lot.
Question 1:
My question is about the field outside the plates of parallel plate capacitor. It is said that the field(s) between positively and negatively charged plates gets added up but the field(s) outside the plates gets...
Homework Statement
I have attached a problem from within the chapter of my book. I have a question regarding my highlighted part.
My question:
Is the reason they are saying E= -Q/(ε0A) because they defined the positive "s" axis to the right? and since E is pointing from right to left we say...
I have two isolated plates A and B, kept parallel to each other. Now I give charge +Q to the plate A, it will redistribute itself as +Q/2 on the outer plate A and + Q/2 on the inner plate A. Right?
Now this will induce charge -Q/2 on the inner plate B and +Q/2 charge on the outer plate B...
Consider the scenario
Two parallel plates
One ion particle (mass 1, charge +1) traveling parallel to the plates through the middle. Voltage of the plates is the same.
As the ion travels between the plates the voltage on the plates ramps up, and the electric field between the plates remains...
I am having a hard time understanding the whole idea behind and the difference between disconnected vs connected parallel plate capacitor in terms of voltage and charge. How does this relate to the formula C(Q/V)=ke0A/d?
Homework Statement
The capacitor (of thickness d) is disconnected from a potential source of V and a dielectric of thickness t is inserted and it has relative permitivity Er. Find the new potential between the plates
Homework Equations
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This is the answer : Vf = V/d(d - t + t/Er) The...
Homework Statement
A proton is released from rest at the positive plate of a parallel plate capacitor. It crosses the capacitor and reaches the negative plate with a speed of 50,000 m/s. What will be the final speed of an electron released from rest at the negative plate?
Homework Equations...
Homework Statement
Find the total amount of energy of a charge (q) initially at rest placed at the left plate of a parallel plate capacitor. The left plate is at V = 0, the right plate at V = V0 and the plates are a distance L apart.
Homework Equations
Etot = 1/2 mv2 + qφ(x).
φ(x) = Vx/L
The...
Homework Statement
Each plate in the figure has area a and separation d , end of battery is e find charge supplied by battery
Homework EquationsThe Attempt at a Solution . each facing plate will have half the charge supplied by battery, but I am...
hi, I wonder that inclined plate capacitor formula is the formula in last picture I shared? I am not sure because there are not enough examples about that ?
Homework Statement
Homework EquationsThe Attempt at a Solution
The force between the plates is given by (1/2)QE ,where Q is the charge on the plates and E is the electric field between the plates .
Now Q = CV and E = V/d , where C is the capacitance , V is the potential difference and d is...
Homework Statement
Homework EquationsThe Attempt at a Solution
Assuming the current is steady,
I = JA, where J is the current density and A is the cross- sectional area
##E = J/\sigma##
Can I take ##\sigma ## uniform here ?
Energy of a parallel plate capacitor with charge Q and potential difference V can be calculated in two ways:
1)Work done in bringing charge dq from infinty to the capacitor when there is potential V= q/C on the positive plate and V= 0 on the negative plate is dW = (q/C)dq
integrrating from 0 to...
How to find capacitance of parallel plate capacitor separated by conducting material with two different dielectric between
Two parallel plate of Cu(5*6*0.1)mm and distance between them is (d=2mm)
a thin Cu-plate of thickness 0.1 mm separates Mica layer & Quartz layer.
how to find capacitance?
Homework Statement
A proton is released from rest at the positive plate of a parallel-plate capacitor. It crosses the capacitor and reaches the negative plate with a speed of 51000 m/s .
What will be the final speed of an electron released from rest at the negative plate?
Homework Equations...
Homework Statement
Homework Equations
The only equations I can think to use would be:
But I'm not sure if they are useful or how they will help.
The Attempt at a Solution
I have the solution, it just isn't detailed...
I don't understand where they get E=1/2ε. Should I be considering...
Homework Statement
A parallel-plate capacitor is connected to a 100 V battery until it is fully charged. The distance between the plates is d and the space between the plates is filled with air (k=1.0). Then, the battery is disconnected. If the distance between the plates is increased to 3d...
Homework Statement
Two parallel plates 1.40 cm apart are equally and oppositely charged. An electron is released from rest at the surface of the negative plate and simultaneously a proton is released from rest at the surface of the positive plate. How far from the negative plate is the point at...
HiI’ve been reading for a while and decided to ask , suppose we have a parallel plate capacitor with a distance x between the plates , in between the plates are another two plates with a dielectric so in total 4 plates. The outer two are attached to a dc supply of 12volts for example.
Now I...
Hi,
A time-varying (sinusoidal) voltage source is applied to a parallel plate capacitor of length d. Then the E field will vary according to E(t) = V(t)/d. However, this suggests that, for any given time, the E field is constant with respect to spatial coordinates. Therefore, the curl of E is...
Homework Statement
An electron is launched at a 45∘ angle and a speed of Vo = 5.0×10^6 m/s from the positive plate of the parallel-plate capacitor towards the negative plate. The electron lands 4.0 cm away.
Homework Equations
F = ma = qE
v = d/t
s = vt -(1/2)at^2
x = 0.04 m
The Attempt...
Hi,
My setup for measuring parallel plate capacitance consists of an LCR meter and a parallel plate test fixture. The area of the parallel plates is much larger than the area of the samples I am measuring. From what I've seen in literature, and my physics classes, the sample area should be...
Homework Statement
A parallel plate capacitor of area 60cm^2 and separation 3mm is charged initially at 90 micro coulomb. If the medium between the plates get slightly conducting and the plate loses charge initially at the rate of 2.5 *10^-8 C per sec then what is the magnetic field between the...
Homework Statement
A parallel-plate capacitor has a plate area of .3m^2 and a plate separation of .1mm. If the charge on ech plate has a magnitude of 5*10^-6C then the force exerted by one plate on the other has what magnitude
Homework Equations
Q=E Ԑ A
F=qE
The Attempt at a Solution
so to...
Homework Statement
The charge on the 3.00 cm2 area plates of an air-filled parallel plate capacitor is such that the electric field is at the breakdown value. By what factor will the maximum charge on the plates increase when bakelite is inserted between the plates? (The dielectric strength of...
in deriving the capacitance of a parallel plate capacitor why do we take the field between the capacitors as σ/∈ and not 2σ/∈,when there are two plates and in the region between the capacitors, field must add up so shouldn't it be 2σ/∈?
Homework Statement
Consider a parallel plate capacitor of area A and separation d. The plates are isloated. One has charge +Q and the other -Q. An isolated conducting plate of area A and thickness t is inserted between the plates as shown.
a. Find the E fields between the conductors
b. Find...
Homework Statement
When a dielectric is partially inserted between two plates of a capacitor that is disconnected, what will be it's motion? Also what will be its motion if the capacitor is connected to a battery?
Homework EquationsThe Attempt at a Solution
For the first part. I think the...
Hi everyone. I have a problem with my device. It consists of a parallel plate capacitor with plates made of galvanized iron. Each plate's area is 1mx1inch. It's connected to a bleeder resistor and basically, the circuit is just a simple RC circuit. The source I'm using is a constant 5V DC...
Homework Statement
Consider a parallel-plate capacitor, with two square plates of side \mathrm{12.0 cm} separated by a \mathrm{4.50- mm} gap. Half of the space between the gaps is filled with a material of dielectric constant \mathrm{K = 3.40}, while the rest is filled with just air.
(a) What...
Hello! I'm hoping someone can help me with my problem. I'm currently working on a low cost parallel plate capacitor. I used a galvanized iron as the plate material since this is a low cost material. The problem is when I measure the voltage across the capacitor, the voltage read peaks at a...
Can anyone please tell me whether I have solved this question correctly or not.
1. Homework Statement
A parallel plate capacitor has a charge of 0.040µC on each plate with a potential difference of 240 V. The parallel plates are separated by 0.20 mm of air. What energy is stored in this...