Capacitors Definition and 868 Threads

Say we have a simple circuit with just a battery and two capacitors. Why must the voltage of each capacitor in series add up to the total voltage of the battery? It seems intuitively plausible, I admit. But can someone show how to go about proving this using the laws of electrostatics ( please...

A capacitor of C1 = 10 F is connected to a battery, and a charge of 100 C builds up on the capacitor. Then, the battery is disconnected, the capacitor is discharged, and a second capacitor of capacity C2 = 20 F is connected to it in parallel. Then, the two capacitors are connected to the same...

1. The problem statement The capacitors in the figure are initially uncharged and are connected, as in the diagram, with switch S open. The applied potential difference is Vab = + 210 V. What is the potential difference Vcd? Homework Equations (series) 1/C = 1/c1 + 1/c2 + ...

Homework Statement An air-filled capacitor consists of a conducting sphere of radius a, surrounded by a concentric conducting spherical surface of radius b. A charge of 2Q is placed on the inner sphere and –Q on the outer surface. Calculate the electric field strengths E(r), (i) between the...

Homework Statement so, we have a capacitor which has capacitance C1 and charge Q0. This capacitor is connected to a second one (capacitance C2) with initial charge Q=0. The capacitors are in a series fashion with no voltage source. What charge does each carry now? Also find the potential...

Capacitors in "Common Emitter Amplifier" Circuit ? Should i use Capacitors in "Common Emitter Amplifier" ( CEA ) Circuit ? As i saw many CEA circuits designed without any capacitors there ! And also hear that it's better to use two capacitors, one after the Voltage Source ( that feeds the...

Capacitors - Voltage [ Solved ] Can you explain me the steps of solving this problem and write the process/calculation ? Thank you very much.

Homework Statement The preceding problem was an artificial model for the charging capacitor, designed to avoid complications associated with the current spreading out over the surface of the plates. For a more realistic model, imagine thin wires that connect to the centres of the plates (see...

Homework Statement Find the steady state expresion for i(t) in the circuit if Vs=750 Cos(5000t) mV All componets are in series Resitor = 400 Ohms Inductor = 40mH Cap = .4 \muF Homework Equations Xc= 1/(j*w*C) Xl = j*w*L Xr = R The Attempt at a Solution Ok I know...

Homework Statement Two capacitors, with capacitances of 4.10 uF and 5.90 uF are connected in parallel across a 660-V supply line. The first questions all relate to finding the charges on each capacitor and the voltage across each one. I can do all of these with no problems. But then it...

Ok so here is the situation. Let's say I have a circuit like this. http://img525.imageshack.us/img525/2883/excap1sp8.jpg The 10 microfarad cap is connected to the 3 volt battery in series. So its charged and has 3 volts. Then we flip the switch. The 10 microfarad is connected to the 20...

Homework Statement A fat wire, radius a, carries a constant current I, uniformly distributed over its cross section. A narrow gap in the wire, of width w << a, forms a parallel-plate capacitor, as shown in the figure above. Find the magnetic field in the gap, at a distance s < a from the...

A coil, a capacitor and an AC source of RMS voltage 24 V are connected in series. By varying the frequency of the source, a maximun RMS current of 6 A is observed. If this coil is connected to a battery of emf 12 V and internal resistance 4 \Omega, the current through it will be (a) 2.4 A (b)...

Note: This is a question about a physics experiment. As such, it does not completely fit into the provided template, but I'll do my best to stick to it anyway. Homework Statement The problem is about an experiment about parallel plates capacitors. The experimental setup is the following...

Hi, If I have two capacitors C_1=1 \mu F ... C_2=2 \mu F,and I start by taking each and connecting it to 5V battery in series, so the first cap has Q_1=C_1 V=5\mu C then seperatley I connect the other cap to another 5V source so it gains charge Q_2=C_2 V=10 \mu C. Now I remove the...

Homework Statement Capacitors C1 = 5.95 μF and C2 = 1.90 μF are charged as a parallel combination across a 277 V battery. The capacitors are disconnected from the battery and from each other. They are then connected positive plate to negative plate and negative plate to positive plate...

Homework Statement Two parallel-plate capacitors A and B are connected in parallel across a 620.0 V battery. Each plate has area 100 cm2 and the plate separations are 4.5 mm. Capacitor A is filled with air; capacitor B is filled with a dielectric of dielectric constant 2.2. A)Find the...

Capacitors C1 = 10 µF and C2 = 23 µF are each charged to 9 V, then disconnected from the battery without changing the charge on the capacitor plates. The two capacitors are then connected in parallel, with the positive plate of C1 connected to the negative plate of C2 and vice versa...

Really, after I became an electrical (control) engineer, until now i do not know why capacitors like Electrolytic and Tantalum Ones, have polarity. can anybody answer me please?

Homework Statement A parallel-plate air capacitor is made by using two plates 10 cm square, spaced 4.7 mm apart. It is connected to a 15 V battery. If the plates remain connected to the battery and the plates are pulled apart to a separation of 9.9 mm. What is the new capacitance? What is...

Homework Statement Two capacitors are connected parallel to each other and connected to the battery with voltage 30 V. Let C1 = 9.8 micro F,C2 = 4.0 micro F be their capacitances. Suppose the charged capacitors are disconnected from the source and from each other, and then reconnected to each...

Hey all, I have a diode clamper (1 diode) and I had to use a capacitor in lab to smooth out the output (the input was a triangle wave - without the capacitor the output was still a bit triangular at the tips). This is just curiosity - can anyone explain to me how the capacitor managed to smooth...

I seems very simple, and I'm sure I understood it before, but for some reason I suddenly started to get confused with it when we want to know the capacitance of 2 capacitors in series, we assume they both have the same charge on them, so I just want an explanation to why does it have to be...

If two dielectric materials with dielectric constants k1 and k2 and thickness d1 and d2 are within two copper plates, how do you obtain a capacitance given that the cross sectional areas are all the same?

A 2.41microF and a 7.38microF capacitor are connected in series across a 30.0-V battery. A 10.3microF capacitor is then connected in parallel across the 2.41-microF capacitor. Determine the voltage across the 10.3-microF capacitor. How do i approach this question. do i start by finding the...

A 2.41microF and a 7.38microF capacitor are connected in series across a 30.0-V battery. A 10.3microF capacitor is then connected in parallel across the 2.41-microF capacitor. Determine the voltage across the 10.3-F capacitor. How do i approach this question. do i start by finding the total...

Okey guys, here's another difficult capacitor circuit... Homework Statement Find the proportions (the quotient) between the energies in the two capacitors when the switch is closed in the circuit below. Homework Equations (1) C = Q / V (2) W = CV^2 (3) Current division (maybe?): I2 =...

Hi Guys, I hope you can help :biggrin: A friend and I are having a debate about capcitors and now we are both a bit confused! So I have a few questions. Firstly, if you take for example a 10,000uf capacitor charged to 12v, then connect it in parellel with an uncharged capacitor that...

What is the use of having capacitors in fans, cooler motors or other electric motors ?

Homework Statement See capacitor design in attachment. Calculate the equivalent capacitance of the circuit shown in the diagram above; where C1 = 4.30 uF, C2 = 7.15 uF, C3 = 2.25 uF, and C4 = 3.75 uF. How much charge is drawn from the battery? Homework Equations Parallel C = c1...

A friend asked me this question: There is a capacitor with capacitance C, charge Q on either plate and an electric field E between the plates. The energy stored in the capacitor is then given by (C.V^2)/2, where V is E.(distance between plates). Now, take another similar capacitor, and...

You have a plate capacitor which is grounded on the bottom and is held at a potential V which is then set to 0. You are given the length of the plates and the distances between them. A test charge is brought in with the charge and mass given along with its velocity. For a vanishing magnetic...

Homework Statement a 5 microfarad capactior and a 10 microfarad capacitor are connected in parallel across a 50 volt battery as shown. the battery is disconnected and the two capacitors are separated from one another without altering the charge on either one. oil with a dielectric constant of...

[SOLVED] Capacitors with partial dielectrics Homework Statement Consider two parallel-plate capacitors identical in shape, one aligned so that the plates are horizontal, and the other with the plates vertical horizontal: vertical: The horizontal capacitor is filled halfway...

[SOLVED] Capacitors: Explain result from experiment Homework Statement I made an experiment today at school with a parallel plate capacitor. I induced 100 V and increased the distance between the plates. I measured the charge and calculated the capacitance of the capacitor, which of course...

Homework Statement The sketch below is a side view of two capacitors consisting of parallel plates in air. The capacitor plates are equal in area but the plate separation differs as shown. Individual capacitors are specified with two letters, for example WX is a single capacitor. The charge on...

It's a problem were we are given the usual - 2 plates separated in air, distance D apart, each of length L, one excess +ve charge the other exces -ve charge The question then states: the magnitude between the e-field plates is: E = q/EoL, calculate the potential (blah blah..) My question...

Homework Statement Q17. Capacitors C1 and C2 are connected in series and a potential difference is applied to the combination. If the capacitor that is equivalent to the combination has the same potential difference, then the charge on the equivalent capacitor is the same as: A. the charge...

Homework Statement Given an electric potential of Vo*sin(wt). This is applied to a parallel plate capacitor of area S, separation d and capacitance C. The questions are a) What is charge Q on the plates? b) Find the electric displacement current c) Calculate the current in the wire...

A point charge of mass 0.0836 kg and charge q = +6.84 μC is suspended by a thread between the vertical parallel plates of a parallel-plate capacitor, as shown in the figure below. If the angle of deflection is θ = 22.3°, and the separation between the plates is d = 0.0221 m, what is the...

Homework Statement I encountered the following capacitor problem on a recent test and it has brought up a couple of questions about the voltage and electric field of parallel plates. In summary my questions are: 1) How is the electric field between parallel plates quantitatively related...

Homework Statement The sketch below is a side view of two capacitors consisting of parallel plates in air. The capacitor plates are equal in area but the plate separation differs as shown. Individual capacitors are specified with two letters, for example YW is a single capacitor. The charge on...

I'm a bit stuck with rectifier circuits. can anyone tell me what the function of a capacitor is in a rectifier circuit please. Thanks, Dave

What is cause of capacitor breakdown? When we combine different capacitors in series and parallel combination, how does the breakdown voltage of the system get affected?

1. Two capacitors, C1 = 60.0 nF and C2, were connected in parallel with a power supply with E = 12.0 V. The two capacitors were then disconnected from the power supply and from each other and were reconnected with the positive terminal of one connected to the negative terminal of the other...

1. 2. Homework Equations : are too big to post here, meaning, I will give you a link to my work: http://farm4.static.flickr.com/3092/2369876018_5866bfb312_o.jpg" 3. The Attempt at a Solution : that's above as well, I know what the solution IS, it's at the top righthand corner of...

I've been working through our physics book for year 12 Physics, and only just now when we've hit electronics has it really confused me. I'd like to be able to understand it before our current 2 week school break ends. Perhaps the biggest flaw of the book is that it doesn't say how it got...

How many volts would i need to make a 100uF 10V capacitor explode if i plugged it in backwards?

[SOLVED] Capacitors VERY QUICK EASY QUESTION! PLEASE HELP! Homework Statement A parallel-plate capacitor has circular plates of 8.80 cm radius and 1.50 mm separation. (a) Calculate the capacitance.

Homework Statement http://img512.imageshack.us/img512/6864/59797183jd5.png (capacitance in micro farads). Initially the switch is at the left position and capacitors C_2 and C_3 are uncharged. Then the switch is flipped to the right position. Afterward, what are the chard on and the...