Capacitor Definition and 1000 Threads

Homework Statement A parallel plate capacitor (capacitance C) is charged with a battery of emf V volts. A dielectric slab of dielectric constant K is placed between the plates to fully occupy the space. The battery remains connected. What are the changes in-1)C 2)Q (charge on capacitor) 3)E(E...

Homework Statement Two capacitors of 1 and 2 micro-farad respectively are each charged by being connected across a 5 V battery. They are disconnected from the battery and then connected to each other with resistive wires so that plates of opposite charge are connected together. What will be the...

Homework Statement A constant potential is maintained across a parallel plate capacitor. A dielectric slab is slowly inserted between the plates (width of slab=distance between the plates). What will the direction of force applied by capacitor on dielectric be? Homework Equations All relevant...

Homework Statement [/B] After how many time constants is the stored energy of a discharged capacitor one-fourth its initial value? Homework Equations [/B] (1) U = Q2/2C (2) U = Qmaxε/2 (3) q(t) = Qie-t/RC The Attempt at a Solution The solution can be correctly attained using the first...

I was recently solving a problem that involved a circuit with a capacitor that was connected to a battery at one end(the second plate just had a wire which didnt lead anywhere). In the solutions it said that this capacitor cannot have any charge since there is no path for the current to flow...

Homework Statement I calculated the capacitance of two concentric conducting spherical shells of radii a and b (a<b) when the inner shell has charge Q and outer has charge -Q correctly by using C=Q/(V(i)-V(o)), the problem I have is described below in "attempt at a solution" Homework...

Homework Statement I was reading through the principle of a capacitor and I am unable to understand one of the statements. My textbook says the following- Consider an insulated metal plate A. Let it be connected to a voltage source and charged to a maximum. Now an uncharged plate B is brought...

Hi, I was reading the capacitor and its operation and it is written there that when the DC is applied to the capacitor it becomes open circuit. The main mechanism behind this phenomena is explained as below:- "When DC voltage is applied the charge started accumulating on the plates of the...

I have a plate capacitor connected to a battery with a known potential difference. Now the plates are moved apart by dx and I must figure out the change in energy stored in the battery. Question 1: When a plate capacitor is connected to a battery charges must flow until the potential difference...

Hi. Is it correct to say that an inductor with a state, that is some level of current inside it, and a capacitor with some voltage, are equivalent to a current source (in the case of an inductor) and a voltage source (in the case of a charged capacitor) respectively at that instant of time? Of...

Hi all, I'd appreciate help in calculating the voltages in the circuit shown. I thought it should be fairly straight forward, but it has me stumped. This is a sample-and-hold circuit for an ADC -- the switch is closed to charge the hold capacitor with the sample voltage and then opened to...

If voltage is the difference in charge between 2 points, then why for a capacitor of a larger area or thinner dielectric cross section, do they say that it can store more charge given the same apppied voltage? Isnt voltage the difference in charge between 2 points? So if you can store more...

Suppose a spherical capacitor is being charged. In this case the E field between the plates is growing with time which implies a displacement current which in turn implies a B field. How would one find this B field if it does exists? I'm guessing the B field is zero because of symmetry. I...

I'm not really sure if this is even scientific but while calculating how much energy is stored in electromagnetic coils and capacitors, pretty much the same formula is used: For electromagnetic coils it's U=0.5LI2 For capacitors it's U=0.5CV2 Why I think they're the same is that in a sense L to...

Homework Statement Homework Equations V = I R Q= CV The Attempt at a Solution When the switch is connected to position a : 20-106 * I = 0 ( KVL) Vc = 0 , because the switch is connected for a long time. I = 2*10-5 A When the switch is connected to position b : Q/(4*10-6) - 106 *2*10-5 = 0...

Homework Statement The capacitor is changed so that the largest possible current is supplied by the source. Enter the value of the capacitive reactance when this change is made. Give your answer in Ohms (Ω). A unit is not required with your answer. Homework Equations The circuit is powered by...

Homework Statement Defibrillation[/B] is a common treatment for life-threatening cardiac arrhythmias and ventricular fibrillation. The defibrillator applies a current across the heart (shown by the red arrows in the image below) for a short time (a few milliseconds), disrupting the arrhythmia...

Problem: At the instant ##t=0## the capacitor C1 has a charge ##Q_0>0## and the capacitor C2 has no charge. (I forgot to draw the switch to close and open the circuit), so the switch is closed and the current start flowing. Let the circuit goes to ##t\to\infty##. a) What's the energy stored in...

Homework Statement Homework EquationsThe Attempt at a Solution Force between capacitor plates is Q2/(2Aε0) . If the distance between the plates is small as compared to the area , then force between the plates does not depend on the distance . But I am not sure how to deal with this problem .

See attached photo for circuit diagram. The switch S has been open for a long time. Determine the magnitude of the electric charge stored by the capacitor. Use the following data: C = 3.43 mF, ε1 = 11.0 V, ε2 = 31.9 V, R1 = 3.66 Ω, R2 = 5.04 Ω. I understand how to determine the magnitude of...

Homework Statement Homework Equations ##Q=CΔV## ##V=IR## The Attempt at a Solution Is my answer correct ?

Homework Statement Homework EquationsThe Attempt at a Solution I don't understand why would the current be zero in any of the branches . May be I am missing something very fundamental . Please help me understand this question .

Homework Statement Homework EquationsThe Attempt at a Solution [/B] Sorry for the unclear image . There is a wire across the combination of 2μF and 3μF capacitors which means the two capacitors are shorted . The whole of 6V drops across the 1μF capacitor . In that case charge on the 2μF...

Homework Statement Homework EquationsThe Attempt at a Solution In the steady state , there will be no current through the two branches containing the two capacitors . The capacitors can be replaced by open circuit . I need to find potential difference across the two capacitors which will...

Homework Statement Homework EquationsThe Attempt at a Solution I often do circuit. But still there is always stuff i don't get.. I was asked to find 1) I1 I2 I3 immidiately after S closed 2) I1 I2 I3 after sufficient of time 3) I1 I2 I3 immidiately after S opened Just give me clue please...

Homework Statement Two parallel-plate capacitors with the same plate separation but different capacitance are connected in parallel to a battery. Both capacitors are filled with air. The quantity that is NOT the same for both capacitors when they are fully charged is: A. potential difference...

Hi, I have a problem understanding the ac capacitive circuit, where Vc = Vm * sin(ωt), and, current leads the voltage, so at t = 0, v = 0 which means no emf, no pushing energy for the electrons, I think, then how current is max? what is the energy source that supplied the electrons with the...

Homework Statement I am very lost, I tried everything I can do to find the voltage/stored energy for each capacitor, but no luck. I know that for parallel, V1=V2=V3 etc and stored energy is Q1+Q2 etc. And for series it's the opposite, but I'm getting completely different numbers for both of...

When capacitor is leaking ie, when charge is leaking or when it is discharging then will there be any magnetic field between the parallel plates of capcitor?

Homework Statement A capacitor with initial charge q0 is discharged through a resistor. What multiple of the time constant τ gives the time the capacitor takes to lose (a) the first 1/8-th of its charge (b) 7/8-th of its charge? Homework EquationsThe Attempt at a Solution since ı know...

An ideal capacitor has power factor of zero degree leading as current leads the voltage in capacitor.But it also means that capacitor is generator of lagging reactive power.What does that mean.How does it do so.Capacitor is used for reactive power generation at inductive load sites.

Homework Statement I have to rearrange the equation V=lnVo -t/RC to calculate C. The gradient from graph = -1/RC Homework EquationsThe Attempt at a Solution I got R/C=ln(Vo-V)/t but the answer I get is wrong

Homework Statement Homework Equations I am to use korchkoffs method to solve this problemThe Attempt at a Solution I already solved for the overall current which is the same throughout because C1 and C2 impeded current flow in sections of the circuit and i have found the charge on c1 BUT I...

Hi everyone, I'm new to this forum so I apologise in advance if I may have posted in the wrong forum or made a similar error. I recently conducted an experiment with some peers where we measured the voltage across a charging capacitor in an RC circuit over a period of time. The diagram is...

[FONT=verdana]Dear Everybody, Using the exact exponential treatment, find how much time (in s) is required to charge an initially uncharged [FONT=verdana]140 pF[FONT=verdana] capacitor (C) through a [FONT=verdana]77.0 M[FONT=&quot]Ω[FONT=verdana] resistor (R) to...

Homework Statement fig 1 : Area of each plate is S, separated by 2d, charge Q in the capacitors fig 2 : uncharged conductors of area S, thickness d, inserted parallel between plates What is the ratio of electrostatic energy in fig 2 to electrostatic energy in fig 1? Homework Equations Q =...

Homework Statement C1 = 4 micro F C2 = 8 mF R1 = 4 ohm R2 = 8 ohm V = 12 Questions : 1) Find current I when S not closed 2) find Vb, when Vc is 0 3) find Vd, when Vc is 0 4) total charge move from B to D Homework Equations Vf - Vi = F.d/q (not sure this below is useful equations) I = E/Z E...

hello, can somebody help me? i found this am receiver, but is using variable capacitor, how can i replace of do with varicap this circuits(i hava varicap bb112)

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...

Homework Statement A parallel plate capacitor has area A = 1 cm2 and a plate separation of d = 0.01m. Water at room temp (20°C) is poured into a ziplock bag and placed between the plates filling the volume of 1cm3. Find the maximum capacitance, voltage and charge for the capacitor. Homework...

Homework Statement (a) A parallel plate capacitor has area A = 1 cm2, a plate separation of d = 0.01m, and is filled with air. If the breakdown field is E0 = 3 × 106V/m, calculate the maximum voltage and charge the capacitor can hold. Homework Equations dielectric constant of air = 1 Q=CV...

Homework Statement Homework EquationsThe Attempt at a Solution Apologies for the question image not being very clear . I will refer capacitors by numerical value of their capacitance . The 6 , 4 , 8 capacitors are in parallel . 9 , 9 , 7 are shorted out .So , we can remove them from the...

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 Ignore those darkened black lines as they are just consequences of my editing and there's a SWITCH" between A and C2 which is opened initially So here's the question I was working with. The switch is closed at t=O,find the charges on the capacitor.The batteries are both 2OV...

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capeng2.html#c1 So I have some doubts in this. All I could understand from the derivation is that the battery is doing external work in pushing the electron from the positive plate to the negative plate and this is what is converted into energy...

I understand the basics of how capacitors work. If you hook one up to a power source, negative charge will build up on one plate, and positive charge will build up on the other plate. As the charges build up, an electric field forms between the plates and a potential difference is established...

Homework Statement A charged capacitor consists of two large flat plates, one with positive charge +Q and the other negative charge -Q. An external agent trans an electron from the positive plate to the negative and also transfers a proton from the negative plate to the positive plate. There is...

Could the space (air gap) between two DC charged parallel plates be considered to be a "non-linear" medium with respect to an EMF radiated by a coil contained within that space?

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 [/B] This is the answer : Vf = V/d(d - t + t/Er) The...

hello i buy allmost all thing needed, for buil you own radio circuits 2013, but in electronics shop he told me , there are old, you can find it only in old radio he can't help, those components don't sell anymore, maybe somebody can help me how to find online those component VC1: two-gang...