Capacitors Definition and 868 Threads

"water" as a dielectric in capacitors Homework Statement Why do you think water is not commonly used as a dielectric in capacitors? K=80.4 *K=dielectric constant for water thx for any help

Homework Statement A charge Q is at the origin. A second charge, Qx = 2Q, is brought to the point x = a and y = 0. A third charge Qy is brought to the point x = 0, y = a. If it takes twice as much work to bring in Qy as it did Qx, what is Qy in terms of Q? Homework Equations My main problem...

For a capacitor not connected to a battery, why does the voltage decrease with the insertion of a dielectric. Would it be because the net electric field between the conductors is decreased?

For a circuit of capacitors...can it be generalized that when the battery is removed, each capacitor approaches the same final electric potential, regardless of whether the capacitors were in series or parallel?

Edit: I found out how to solve this but I'd still appreciate some tips (see bottom). Homework Statement Homework Equations Capacitors in series: Q = Q1 = Q2 = ... V = v1 + v2 + ... 1/Ceq = 1/C1 + 1/C2 + ... Capacitors in parallel: Q = Q1 + Q2 + ... V = V1 = V2 = ... Ceq = C1 + C2 + ...

Hi, everyone I am new around here and was wondering if anybody could answer some basic questions for me? 1. I was wondering how you would make an electrical connection or for example a direct connect from a battery to switch the electrons to be only negative or only positive. 2. If you...

Homework Statement An axon is the relatively long tail-like part of a neuron, or nerve cell. The outer surface of the axon membrane (dielectric constant = 5, thickness = 1 *10-8 m) is charged positively, and the inner portion is charged negatively. Thus, the membrane is a kind of capacitor...

Homework Statement A parallel plate capacitor with the separation between the plates as 'd' has its lower plate dipped in water. Before dipping, the lower plate has charge Q, while the upper plate has charge 2Q. Let K be the dielectric constant of water. What will be the final charge on the...

[SOLVED] Infinite capacitors Homework Statement Consider the infinite chain of capacitor problem: Each of the capacitors (C) below in the infinite series circuit has a capacitance of 6.34 mF. What is the capacitance of a single capacitor that can be connected between points A and B to...

Homework Statement How does the loop rule apply to capacitors? I can't find any examples of circuits containing capacitors and resistors where the loop rule is used. I know the loop rule measures potential differences, but I'm not quite sure if that has anything to do with capacitors? All...

Capacitors...Please HELP! Homework Statement An uncharged capacitor is connected to the terminals of a 1.02 V battery, and 1.69 μC flows to the positive plate. The 1.02 V battery is then disconnected and replaced with 6.78 V battery, with the positive and negative terminals connected in the...

Homework Statement Reduce the circuit as much as possible. All resistors have R and all capacitors have same C. Homework Equations The Attempt at a Solution http://photos-a.ak.facebook.com/photos-ak-sctm/v183/24/75/1238100168/n1238100168_30112052_7338.jpg And this is my...

[SOLVED] capacitors yet another question - please help Sir, I have uploaded my two questions along with my solution. Can you just tell me if my solution is correct. The link is: http://img412.imageshack.us/my.php?image=capcitorsao1.jpg

there are two parallel plate capacitors C1 and C2 connected in series across a battery of emf V with a switch S. The capacitor C1 has some initial charge q0 while C2 is uncharged. I want to know will the final charges in the two capacitors be same? if yes, why?

The problem: A capacitor has the capacitance 35nF, the tolerance is max 10V. You have to put 30V over the capacitor . How many capacitors of same kind do you need if you want to achieve same C(35nF) that tolerate 30V? I have translated it from swedish to english, sorry if my english isn't so...

Capacitors - please, need urgent help! Homework Statement I've attached the circuit diagram but it's basically a cell connected in series with a 10kohm resistor, and then a 20microfarad capacitor and 22kohm resistor connected in parallel. The capacitor begins charging at t=0. Show that the...

Homework Statement What is the potential difference across C2 when C1 = 5.0 µF, C2 = 15 µF, C3 = 30 µF, and V0 = 24 V? http://img503.imageshack.us/img503/9994/capacitanceqb1.jpg Homework Equations C = Q/V The Attempt at a Solution I calculated total capacitance of C1 and C3...

Homework Statement Capacitors A and B are identical. Capacitor A is charged so it stores 4J of energy and capacitor B is uncharged. The capacitors are then connected in parallel. The total stored energy in the capacitors is now ____.Homework Equations U = q^2/2C The Attempt at a Solution Ok...

Homework Statement http://img158.imageshack.us/img158/9616/capacitanceqj8.jpg C = 12pF Homework Equations The basic equations for capacitance in series and capacitance in parallel, which I assume everyone knows The Attempt at a Solution Well I calculated the two capacitors in the...

So being fresh from school, a lot of times as students we dealt with unrealistic values for caps and inductors. I remember doing a textbook problem where a cap's value was 1 F. Now that I'm in the real world. What is considered to be a realistic value? To push the question further, I see a lot...

Four capacitors are connected as shown in the figure below (C = 16 mF) (a) Find the equivalent capacitance between points a and b. (b) If V(ab) = 16.5 V, calculate the charge on the the 23.0 mF capacitor. This is repeated for each capacitor in the circuit. For the sake of simplicity, C =...

A 9.0 μF and 4.0 μF capacitors are connected in parallel... Hi, I understand how to do most of this question, I completed "A", but I am confused with question "B". I think that the series capacitor would have full voltage going across it and that the parallel capacitors would have less...

My knowledge on how inductors and capacitors operate in AC/DC is a bit shaky. My textbook and online material don't help my understanding, so I am hoping someone would be able to explain it more clearly. In DC I know that capacitors store energy and charge up by time constants and then...

Two capacitors, C1 = 20 µF and C2 = 5.0 µF, are connected in parallel and charged with a 150 V power supply A.) Energy Stored I found to be is 2.81*10^-1 J B.)What potential difference would be required across the same two capacitors connected in series in order that the combination store...

Homework Statement We begin with two capacitors c(1)=6 microFarad and c(2)=3 microFarad in parallel which are connected to V=24Volts. The charged capacitors are disconnected and is being connected to each other on opposite signs (+ to -). How much Energy is got wasted in the process...

Say we have a parallel plate capacitor which is charged using a DC source. In my understanding there is a build up of excess positve and negative charge on opposing plates of the capacitor (depending on which plates are connected to the positive and negative terminals of the DC source)...

consider the plates ofa capacitor suppose u just have two capacitors connected in series then consider the two plates not connected to the battery that form a seprate system .one of them has +Q and the other -Q then how is that there is no flow of charges between them because one of them...

Ok, I have 2 homework problems that I don't really know where to even start. The first one is: A homemade capacitor is assembled by placing two 15-cm pie tins 20 cm apart and connecting them to opposite terminals of a battery. Calculate the following: a) the capacitance b) the charge on each...

Hi everyone, This is my first post on the forum, but I have used the site many times for previous help. My professor started us on capacitors today and just had time to give us a bunch of equations without much explanation of how to solve problems. A problem he gave us to solve so as so:A 20.0...

Hi. If I had 4 capacitors and three were in parallel while the last one was in series with on of the parallel ones would the charge on the c and d capacitors be the same? Capacitors Cc and Cd are in series while being in parallel with Ca and Cb.

Homework Statement Examine the figure shown. Note that C3 = 10.5 uF, and C1 = C2 = 2C3. Also the battery voltage is Vb = 39.0 volts. Homework Equations What is the equivalent capacitance for this arrangement? How much charge is stored on C1? The Attempt at a Solution C2...

Alright this has been tickling me for the past couple of days. First, I know that the E under an infinite sheet of charge is: E = \frac{p_s}{\epsilon_0}\hat{z}

Can anyone tell me the difference in capacitors. Such as the quality control in producing it, the testings, the specs (low esr), brand names, and if its worth buying a 30 dollars 1.5 farad capacitor v.s. a 170 dollars 1 farad capacitor. thanks

Homework Statement If the switch is flipped from position A to position B, what's the charge on capacitor C1 and C2? Please see the attachment below Homework Equations Q=CV The Attempt at a Solution I know that the capacitor C1 gains potential difference of 200V (=...

The voltage from point a to point b is +28V. Each capacitor has a capacitance of 4.00uF (microfarads) What is the best way to calculate the charge on each capacitor?

Homework Statement hey A 2.21 uF capacitor is charged by a 20.0 V battery. It is disconnected from the battery and then connected to an uncharged 3.60 uF capacitor (Fig. 17-29). http://www.webassign.net/giancoli5/17_28.gif Determine the total stored energy at the following points in...

Homework Statement Find the equivalent capacitance between points a and b for the group of capcitors connected as shown below. http://img250.imageshack.us/img250/7816/40ha4.th.png Homework Equations Series/Parallel combinations. The Attempt at a Solution I don't get how the...

We've been studying capacitors in series in my physics class. I have a problem tonight and I know the answer, I just don't know how to get to it. The problems is as follows: Find the voltage V1 across the first capacitor. Express your answer in terms of V.

Ok here a scanned photo oh my worksheet for physics. I tried and used what I knew for equations to solve. After looking at other sample problems, I am not sure how to find part b and c of the problem. I think I went wrong somewhere. Could someone take a look and guide me in the right direction...

Homework Statement A parallel-plate capacitor has an area of 5 cm^2, and the plates are separated by 1mm with air between them. The capacitor stores a charge of 400pC. a) What is the potential difference across the plates of the capacitor? b) What is the magnitude of the uniform electric field...

Homework Statement (Note: This is the fourth part of a single question, but it's the only part I'm having trouble with. Don't worry, it's not as simple as Q/V. :smile:) "What is the potential difference between a point midway between the [circular, parallel] plates [which are 1.43 x 10-4 m...

Homework Statement A parallel-plate capacitor has plates with an area of 445 cm2 and an air-filled gap between the plates that is 1.51 mm thick. The capacitor is charged by a battery to 575 V and then is disconnected from the battery. There is 4.311536113 x 10 ^-5 J of energy stored in the...

Homework Statement A 10.0 µF capacitor is fully charged across a 10.0 V battery. The capacitor is then disconnected from the battery and connected across an initially uncharged capacitor with capacitance C. The resulting voltage across each capacitor is 4.00 V. What is the value of C...

1. Capacitors C1 = 4.0 µF and C2 = 2.0 µF are charged as a series combination across a 95 V battery. The two capacitors are disconnected from the battery and from each other. They are then connected positive plate to positive plate and negative plate to negative plate. Calculate the resulting...

If you have two parallel plate capacitors side by side and the electric field in one is constant. If you vary the electric field in the other, will it interfere with the electric field that was constant?

My physics textbook kinda offhandly says capacitors can be charged to higher potential differences than the battery used to charge them and uses a camera flash as an example, however it doesn't say how this is done. What it does say is attaching a capacitor to a batter in a simple circuit will...

In the following schematic, will the RC time constant be the same for all capacitors using the equivalent resistance of all the resistors? When I plug it into pspice or electronics work bench, it has that the First capacitors voltage as a function of time will always be twice as much as the...

if anyone could help me on this it would be much apreciated, thanks :smile: . Question: A capacitor was joined across a digital voltmeter and charged to a p.d. of 1V. the p.d. was then measured at 20s intervals and at t=30s a resistor (R=1.5 mega ohms (1500000ohms)) was connected across the...

I'm supposed to show that while a capacitor is being charged, the energy flows into the region between the plates at the same rate as the electrostatic energy in the capacitor increases. I'm not sure exactly what is being asked of me... are there formulae for these? I feel stupid.

I picked up a good and cheap AC motor that came with its own capacitors <not wired in though> The capacitors are these http://www.weisd.com/store2/NTEMRC370V7R5.html and this is the diagram on the motor http://foxhole.kicks-ass.net/diagram.jpg" Now I tried putting this together but with no...