Capacitor Definition and 1000 Threads

Homework Statement Determine the potential difference across the plates of the capacitor of the network shown in the figure. Homework Equations kirchoff's loop rule q=vc 3. The attempt at a solutio applying kirchhoffs law starting at bottom right point, q/c2-E1+q/c1+E2=0 =>E2-E1=-q/c1-q/c2...

All sites and books give different answers for this question:( Homework Statement predict the polarity of the capacitor in the diagram below Homework Equations right hand thumb rule AB is capacitor The Attempt at a Solution The side facing south pole becomes south and north facing side...

Hi, I'm trying to form an expression for a rectifier supplying a DC link with current, without actually rectifying a 3-phase input. Usage of the model is really only concerned with the RMS values and the active power drawn from the AC supply. The DC link is just a capacitor so that: dVDC/dt =...

Homework Statement Homework EquationsThe Attempt at a Solution I have difficulty in solving part (C). The surface bounded by the Amperean loop is like an open drum. The current enclosed by the loop is ## I_{en}## = I through the bottom of the drum + I(s) through that part of the curved...

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 ?

Homework Statement Homework EquationsThe Attempt at a Solution A)Clearly, ##V_A - V_B >0 \\V_C - V_D >0## as the current flows from higher potential to the lower potential. As the time passes on, the potential difference across the capacitor as well as the resistor goes on decreasing...

Homework Statement Uploaded question(the formula in c part) And can you tell me in which all cases that formula is used. Homework Equations Just want to know where the formula in c part has come from. The Attempt at a Solution Sum of magnetic fields due to circular plates calculated and added...

Homework Statement You charge a parallel-plate capacitor, remove it from the battery, and prevent the wires connected to the plates from touching each other. When you pull the plates apart to a larger separation, do the following quantities increase, decrease, or stay the same? (a) C (b) Q...

Homework Statement A capacitor of capacitance C is charged to a potential difference v from the cell and then disconnected from it. A charge Q is now given to its positive plate. The potential difference across the capacitor is now? Homework EquationsThe Attempt at a Solution V is the...

Hi everyone. I need to calculate E-field(AC source / DC/ point charges) in leaky capacitor( epsilonr= a dielectric with relative permittivity and finite conductivity). But I do not how to calculate or write the equations for them. any idea or reference is very welcome.

This post is inspired by a lesson on the allaboutcircuits education website. In chapter 15 of Direct Current there is a heading "Inductors and Calculus" - https://www.allaboutcircuits.com/textbook/direct-current/chpt-15/inductors-and-calculus/ At the bottom of the topic there is a circuit...

So I have been watching his videos trying to get ready for second year engineering (electrical). However, I am very confused as to what exactly is going on when he is pressing the enable/pulse switch during the run-through at 14:45. He has the enable connected to a capacitor, and he calculates...

I have a hard time comprehending excess charge in capacitor plates. Let's say we have two identical capacitor and we charged them to identical amount of charge. Next we connect them in series by opposite sign electrodes and we get double the voltage on the open ends. Now a single capacitor has...

Hello all, I have a simple question about capacitors. We are learning about them in class and in some questions, I seem to come up with different answers than the solution sets, always by 2. I apparently am using the area of each plate in a capacitor to derive my results. My question is when...

Homework Statement I have to find the charge ##q## on the capacitors (all have capacity ##C= 4 \mu F##) and ##\mathscr{E} = 12 V##, ##R=50 \Omega##Homework EquationsThe Attempt at a Solution I wrote the nodes current equations ##\begin{cases} i_{1}+i_{2}=i_{3}\\ i_{3}=i_{4}+i_{5}+i_{6}\\ ...

If a capacitor is charged to 10V where the negative side is connected to ground (0V), when the capacitor is disconnected from the power supply on both the positive and negative sides; 1) Will the negative side of the capacitor still be 0V relative to the ground it was just connected to? 2) Say...

Homework Statement A capacitor of is connected as shown in the circuit. The internal resistance of the battery is Amount of charge on capacitor plates will be : Homework Equations no relevant euqations given. The Attempt at a Solution I don't even know how to begin with the question:(...

Hi, Out of interest, today I was mucking around with a 160W LED, 240V, 50hz, outdoor light. I looked at the Power Factor (it was 0.96) and the THD was 14.something %. I then wondered what would happen if I put a capacitor in parallel with the light. It was a three phase 90uF cap, so since they...

Homework Statement 1. V for C1 2. Let's Say "C" is Resistor then C1 = R1 etc. how to get Eq Resistance for this Circuit ?[/B]Homework Equations Faraday's Law, Kirchoff Law The Attempt at a Solution [/B] for no 1 :I just want to make sure. point A is transfering negative charge to C2 and...

I have question, why can condesator get charged, when connected to voltage source, if for current to flow, there most be closed wire, but here it is not, but there still is current? Thanx for answers.

I am trying to create a high DC voltage output(with extremely low current output). I thought of something like this. The left coil would be the tesla coil. Can I use this to charge the capacitor and create high DC voltage? What would happen if capacitance was really high?

So, I was studying force between the plates of a capacitor when a dielectric is inserted. Here is my question https://ibb.co/cenvXk Shouldn't it be like this picture below https://ibb.co/kOUsCk So, why is my teacher saying that the electric field inside the dielectric cancelling. So, what...

Homework Statement Hi, I've run into two different equations for the voltage of a typical RC circuit, one resistor, and one capacitor. Please explain the different between the two. One has a 1 - the natural log and the other one doesnt. Homework Equations 1. V(t) = Vo*e^(-t/RC) 2. Vc =...

Consider empty spacetime containing a charged capacitor. Is there a simple expression for metric for the spacetime between the capacitor plates in terms of Kaluza–Klein theory? We are told that spacetime tells matter how to move; matter tells spacetime how to curve. Is there a Kaluza–Klein...

Homework Statement A capacitor with C is charged by a battery to a voltage V and then disconnected. The distance between plates is slowly increased by an external force. What is the change of the electrostatic energy of capacitor during this process? Homework Equations I have two ways to solve...

This is a pretty simple question, one that there is likely a simple answer to. So, I need to use a capacitor as a rapid dump battery, not a filter or anything. The required current for this application is 1.7 Amps, and only 0.23 volts is necessary. I'm not too sure as to what amount of farads a...

Homework Statement Homework Equations ##q = CE(1 - e^{-t/RC})##The Attempt at a Solution I assumed that, since the problem specifies that sufficient time has passed, it meant to say that enough time passed. thus making the exponential term in the equation go down to 0, and the charge in the...

Hi PF, I am in need of a capacitance in the zF (zeptofarad = E-21) range. Of course, they aren't sold this small, so I was wondering if maybe someone with more physics knowledge could help me create my own zF capacitor. Thanks in advance!

I guess it is a trivial fact that field must be ##(\phi_1 - \phi_2)/s## but I don't get how ? is there a derivation for it ?

I don't have clear concept on voltage. I am a Mechanical guy. If the gap is irregular in large capacitor, how voltage is derived in theory. Using software I can divide the surface into many pieces and calculate voltage of individual small piece. I attached my problem.

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...

I have a capacitor from a fan. The electrician says it's dead, but I think he is lying. I want to test it with a multimeter. But I can't identify which terminal is positive or negative as it's old and from local company. A poor video of the capacitor is below: A few pics from the video...

Homework Statement : [/B]Two conducting spheres of radii R1 and R2 are kept widely separated from each other. what are their individual capacitances? If the spheres are connected by a metal wire, what will be the capacitance of the combiation?Homework Equations Capacitance of a sphere of radius...

Homework Statement A 2200 µF capacitor is charged to a potential difference of 12 V and then discharged through an electric motor. The motor lifts a 50 g mass through a height of 24 cm. The capacitor is charged to 12 V again and then discharged through a 16 Ω resistor Determine the time...

Homework Statement Question : How much charge is stored on the capacitor C2 ? 2. Homework Equations Q = C . U The Attempt at a Solution [/B] Since Q2, the charge stored on the capacitor, is C2 . (Va - Vb) , I thought that I just had to multiply 1.0 x 60 = 60. But in fact, the expected...

Hi, the solution of my exercise says that the potential difference in the capacitor C1 is zero. Can you please explain me why it's the case ? Thank you.

This is a question from an a level textbook. The R starts at 8k ohms (thought its not relevant) Switch S is closed - C fully charges up. Question:Switch S is opened. Explain why the current decreases and REVERSES direction in the ammeter. This is what I think. The decrease in current is...

Homework Statement I would like to know the initial voltage across the capacitor terminals in the following diagram. Homework Equations when a capacitor is connected to a DC source for a long time, it acts an open circuit. The Attempt at a Solution for t < 0, we get the diagram below and I...

I was reading about bipolar plate batteries, where the plates function as both the anode for one cell and cathode for the next cell, in series. It seems to me that the same idea should work to create a capacitor of higher voltage. If I had a dielectric material that had dielectric strength of...

Homework Statement I have an elementary doubt with the calculation of the capacitance of a capacitor of parallel plates that has a dielectric in the middle. https://ibb.co/b0W4BQ Homework Equations ∫D⋅ds=Q D=E+γP C=Q/V The Attempt at a Solution Suppose the top plate has a positive charge...

Homework Statement 2. Homework Equations [/B] No equations needed The Attempt at a Solution I know that capacitors are used to store charge but what exactly is the 40 micro-farad capacitor doing? No emf/voltage is shown so is the 40 micro-farad capacitor acting like the emf/voltage? or is it...

Homework Statement I'm trying to find the output voltage ripple of a buck converter by using just the waveforms and the inductor ripple. Homework Equations [/B] I know that the answer is supposed to be D(1-D)Vin/(16*L*C*f^2) but I keep getting D(1-D)Vin/(8*L*C*f^2)The equations I end up...

Homework Statement Homework Equations V=Ed Q = CV W = 1/2 QV The Attempt at a Solution Hi. My instructor gave me this problem as a homework. Actually he didnt teach us this subject. So what should i know to solve this question or from where can i study to this subject? Of course it would be...

Homework Statement A capacitor with a capacitance of C = 5.95×10−5 F is charged by connecting it to a 12.0 −V battery. The capacitor is then disconnected from the battery and connected across an inductor with an inductance of L = 1.50 H . What is the charge on the capacitor after a time...

I am researching whether or not there is an equation that calculates energy used by a DC battery to keep a capacitor charged over time in a capacitor circuit. I know a capacitor in a circuit acts as a break when it is fully charged, but does the battery continue using energy to keep the...

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 This is a switching circuit for a switched reluctance motor. At the right hand side of the circuit attached below, there's a 47μF capacitor. What is the need for that? The attempt at a solution Is it to reduce harmonics or ripple, or something of the sort?

Homework Statement The plates of a parallel-plate capacitor are maintained with constant voltage by a battery as they are pulled apart. During this process, the amount of charge must... (decrease , increase , remains the same) Homework Equations C=Q/V C=E0(Area/Distance) The Attempt at a...

Hi , I was measuring the inductor and capacitor value of a resistor bank with a 100Hz and 1kHz using a LCR meter by fluke. I realize that with different frequency, the L and C values were different. If the measured values were the inductance and capacitance I can understand that it changes...

Homework Statement A capacitor (A) of capacitance 4.0uF is charged to a potential difference of 20V. An uncharged capacior (B) is connected in parallel to capacitor A. What is: (a) the initial energy stored on capacitor A (b) the p.d. across A after B has been connected (c) the final energy...