Capacitors Definition and 868 Threads

Homework Statement I am practicing these types of problems, for example: and I am asked to find i(t) in this case, and it is in steady state. I really need someone to walk me through these types of problems, how do I get them started. Homework EquationsThe Attempt at a Solution I am really...

Homework Statement Consider the circuit shown in the figure below, where C1 = 4.00 µF, C2 = 7.00 µF, and ΔV = 22.0 V. Capacitor C1 is first charged by closing switch S1. Switch S1 is then opened, and the charged capacitor is connected to the uncharged capacitor by closing S2. (a) Calculate...

Hi, I am a bit perplexed by the codes on some old ceramic disk New Old Stock capacitors. Here are some examples. This one measures close to 68 pf. CM = MFG ? U2J = ? 75J = I assume 75 pf and the J = the tolerance of 5% 1KV = 1000 volts This one measures around 60 pf. 68J N750 1KV This one...

Dynamos and transformers have inductor coils reacting with changing magnetic fields and importing energy into the circuit in form of induced current 1. What about the counterpart of above principle in case of capacitors? 2. Will capacitors interact with...

Homework Statement I need to find Vc(t) in the following circuit: Homework EquationsThe Attempt at a Solution I was trying to follow an example in my notes. They automatically consider that t>0 it becomes closed and therefore like a short circuit. Can I do that in this case? If I do that...

I've looked at a few videos on how capacitors work, and have a fairly good, if basic, idea of how they charge (current causes collection of opposite charge in plates, creating electric field between two plates), but what I'm not seeing is how they discharge. No videos I've seen have said...

Homework Statement Assume you have C1, C2, C3 capacitors and each one of them have a specific charge. Now imagine you connect them to one circuit (Just as in the picture below). Determine the charge on each capacitor after the movement of charges stop Homework Equations Kirchhoff's law The...

Homework Statement A potential difference Vab = 46.0 V is applied across the capacitor network of the following figure. If C1=C2=4.00μF and C4=8.00μF, what must the capacitance C3 be if the network is to store 2.80×10−3 J of electrical energy? Homework Equations U=(1/2)CV^2 (1/C) = (1/c1) +...

1. Passage of current via coil creates magnetic field (fig a), similarly external magnetic field linked to coil when changed created electric current in the circuit connected ( Faraday's em induction fig b). 2. Charging of capacitor using voltage source creates electric field in the capacitor...

Homework Statement Two capacitors, one that has a capacitance of 4 μF and one that has a capacitance of 12 μF are connected in parallel. The parallel combination is then connected across the terminals of a 12 V battery. Next, they are carefully disconnected so that they are not discharged. They...

Hello! I am bit confused about kirchhoffs law with capacitors. So if I have a battery and resistance, I obtain V-RI=0. But from what I read, if I have a capacitor and resistance (so discharging capacitor), the equation reads R(dq/dt) + q/c = 0, which is equivalent to RI + q/c =0. Why in this...

Hi guys! I am fairly new to the forums so thank you for having me here :) I just wanted to ask some of you guys here who have a better knowledge about high voltage capacitors than me. I am creating a lightning impulse voltage generator as my final year project and have been provided with most...

The other day we were working on a problem which stated : Q charge is given to the positive plate of an isolated parallel plate capacitor of 10 μF. Calculate the potential difference betweeen the plates. Our teacher said that as the plate is isolated, Q charge will be divided between the two...

I have a problem that I have encountered during research. The setup for this scenario is that I am placing two contacts on top of a piece of diamond. What I need to be able to do is calculate the Electric Field at a point within the diamond when I apply a voltage to the contact. The point of...

Is it possible to combine (possibly infinite) capacitors and inductors to get a total impedance which is independent of frequency. If so, how?

i'm fairly new to the world of electricity an was just wondering why capacitors with graphine and carbon nanotubes are better than conventional. is it just due to increased surface area?

Homework Statement A voltage is applied across the capacitor network in the image shown Below (if it loaded I can only see a small panel with IMG on it), which of these individual capacitors has the highest voltage across it Homework Equations...

(Look at the level above) If you have a battery which is made by two plates having opposite charges ( constant E-Field), But outsidethe electric field doesn't cancel out. (The same applies to capacitors) not infinite So the question is why doesn't an electron get affected by a really huge...

What will happen to the force between the capacitor plates (Will increase or decrease or remain constant) if we introduce a dielectric between them? As per the answer given the physics textbook , the force will remain same? But as per my understanding the force should decrease since electrical...

Homework Statement Both diodes are ideal. Answers: (a) Vi (b) -Vi (c) -2Vi (d) none of the above Homework Equations Q=CV The Attempt at a Solution 1. For t=0 to Pi: Cap1 and Cap2 are in series and hence Q1=Q2, therefore Vc1 = Vc2. From this we get Vi = Vc1 + Vc2, hence Vc1 =Vc2 = Vi/2. 2...

Homework Statement A capacitor, is fully charged by a battery. The battery is disconnected and a dielectric is inserted into the capacitor. Which of the following is true? I. Voltage will stay the same II. Potential energy of the capacitor will increase III. capacitance will increase...

Homework Statement My teacher told me that the force will increase ##k^2## times, where ##k## is the dielectric constant, but I don't see how. Homework EquationsThe Attempt at a Solution To start with, with no dielectric, the force between the plates is given by ##\frac{q^2}{2A\epsilon_{0}}##...

So the rate at which a capacitor charges and discharges is dependent on resistance in a circuit and the magnitude of capacitance of the capacitor? So the time constant is equal to RC. So using this equation where Q=Qoe-t/RC ,time constant is the time taken (when the capacitor is discharging)...

So, is this true for when a capacitor charges through a fixed resistor (as shown in the image below, when the switch is closed to 1)- the potential difference across the resistor exponentially decreases to zero and the potential difference across the capacitor exponentially increases from zero...

Homework Statement Homework EquationsThe Attempt at a Solution 1) the first question is easy,it is (C) because these charged balls are repelled from the similarly charged plates and accelerate towards the negatively charged plate,and once thy stick to the second plate they transfer double the...

I'm trying to set up a DC power supply filter for a 2kW motor controller. I'm trying to set up inductance cancelling for the input capacitor array. When I simulate the coupled T filter in the frequency domain I get what I expect to see. However when I simulate the transient response I'm still...

Homework Statement A 4μF capacitor is charged to a charge of 200 μC,and a 3μF capacitor is charged to a charge of 300μC. Both the capacitors are connected so that the positive plates are connected together. What is the total loss of energy in the process? Homework EquationsThe Attempt at a...

When a fully charged capacitor is connected to an uncharged capacitor with different capacitance, would the p.d. across each of them be the same? I thought that only the charge stored on each would be the same so p.d. across each would depend on their capacitance? Does that mean that they will...

can a charged capacitor mathematically be represented as uncharged capacitor connected in series with battery of opposing emf ?

There are a few problems here but it would be helpful if The below solutions could be checked and some insight provided for the last one/any other mistakes The problem & The Solution Attempts A circuit with a 12V battery then on the row below in series with the battery is a 120nF capacitor...

So I basically understand the C = ε0(A/d) formula. Larger area means there is room for more electrons, smaller d means larger E field, which pulls electrons onto the opposite plate more strongly. What's tripping me up is when dielectrics come into the picture. When a dielectric is inserted, the...

Hi. I have a question about conservation of charge when two differently charged capacitors are connected in series. I know this is like a homework problem of introductory level of physics, but since this is not my homework, I decided to post it here. So, here is the story. There are two...

I live in an rv. My power comes from solar and ocassional boost from my generator. I have 3600wh in battery power. But i know its really bad for my batteries to draw lot of power fast. So i would like to create a capacitor bank that would stay charged. Ive done some calculations but not...

Homework Statement Given ZV1 = ZV2 = 100Ω, ZCCV = ZCV = 2000/j = -2000j, and VV/VC = 0.04789. I'm trying to get the given VV/VC result. Homework Equations I know that 1/ZV = 1/ZV1 + 1/ZV2 + 1/ZCV VV = ZV / (ZV + ZCCV) * VC The Attempt at a Solution 1/ZV = 1/ZV1 + 1/ZV2 + 1/ZCV = 1/100 +...

Homework Statement I am trying to derive the equation for the charge of a capacitor as a function of time: Q (t) = Qmax (1-e^(-t/tau). Homework Equations Kirchhoff's loop law I (t) = dQ(t)/dt Delta Vbat= Epsilon Delta Vresistor= -I*R = [-dQ(t)/dt]*R Delta Vcapacitor= Q/C Qmax = C*Epsilon Tau =...

Hello, I have a bit of a problem with my project and it is as follows: I am trying to discharge a capacitor bank (2x 470uf 400V capacitors in parallel). I tried making a MOSFET switch to use that as a switch, but it kept burning out the mosfets (they were rated for 600V and around 100A), then I...

When we run our Gensets individually, we are getting a Power Factor of 0.55 and 0.65 for our 250 KVA and 365 KVA Gensets respectively.3. An Electrical Engineer advised us to install a 90 KVAR Power Capacitor and an Automatic Power Factor Control Panel to get a PF of 0.85 for our existing load...

Assume you have a simple battery-bulb-capacitor circuit. If you replace the capacitor with one that has twice the area as the old capacitor, the bulb will stay on longer because there has to be more charge to accumulate on the plates of the capacitor to zero out the net electric field...

In the figure below, a potential difference V = 150 V is applied across a capacitor arrangement with capacitances C1 = 12.0µF, C2 = 6.00µF, and C3 = 16.0µF. Find the following values. Here's the diagram: http://www.webassign.net/hrw/hrw7_25-28.gif I already solved this problem but I'm having...

Homework Statement Three capacitors ##C_a = C, C_b = 2C, C_c = 3C## are positioned like in the figure. The A capacitor's electrode has a ##V_a = 20 V##, while the B capacitor's electrode has a ##V_b = 80 V##. What is the electric potential ##V_3## of the C capacitor's electrode? Homework...

so I am facing the need for low esr and high ripple current for a smps output filter after rectifier. Would it be better in terms of both ESR and ripple to put say 8x470uF in parallel or 4x1000uF ? Or maybe there wouldn't be a big difference ? Assuming both caps are with a low esr and high...

To my understanding, capacitors cause the current to lead the voltage which adds VARS to the circuit and inductors cause the current to lag behind the voltage which removes VARS (in AC circuits). Also, it is my understanding that VARS increase voltage. I work for one of the largest utilities...

Homework Statement This is not necessarily a homework question, just a conceptual one. I was reading up on capacitors, and an example said that a 25uF capacitor has TWICE the impedence of a 50uF capacitor. Can someone explain what this means? I would have thought that a capacitor with higher...

Homework Statement imgur link: http://i.imgur.com/TWB5rRu.png Homework EquationsThe Attempt at a Solution I can find the equivalent capacitance, 10F, but I'm not really sure how to find the equiv. Thev. voltage. I figured that with the voltage source present, half the voltage will be lost...

Homework Statement Fig. 25-39 shows a 12.0 V battery and four uncharged capacitors of capacitances C1 = 1.00 µF, C2 = 2.00 µF, C3 = 3.00 µF, and C4 = 4.00 µF. If only switch S1 is closed, what is the charge on (a) capacitor 1, (b) capacitor 2, (c) capacitor 3, and (d) capacitor 4? (figure at...

Homework Statement A potential difference of V = 38.0 V is applied across a circuit with capacitances C1 = 4F, C2 = 5F, and C3= 2F, as shown in the figure. What is the magnitude and sign of q3l, the charge on the left plate of C3 (marked by point A)? What is the electric potential difference...

Hey everyone! I have a doubt that relates to energy stored in different capacitors (when they're in a circuit). I understand how in capacitors connected in parallel, the capacitor with the biggest capacitance stores the most energy because: E = 1/2 CV2 So naturally the bigger the capacitance...

Homework Statement I am having trouble simplifying a circuit of capacitors that I was given. I am asked to determine the equivalent capacitance of the combination below (attached photo). Homework Equations Capacitors in series: 1/Ceq = 1/C1+1/C2+... Capacitors in parallel: Ceq = C1 + C2 +...

Hello everyone, I have a doubt about charging of capacitors in series. Suppose I connected two capacitors of same value, say,1 mF in series and put a bulb in series with them and applied a voltage 10V across the series. In steady state, the voltage across each capacitor will be 10/2=5V. Right...

Will this circuit work for maintaining a dc bias on the capacitors? I am under the impression that there is +4 v at point A; even if an emf charges and discharges the capacitors. I worry that current will flow into the battery.