Capacitance Definition and 903 Threads

When I try to do Gauss, the permeability is not always that of the free space, but it varies: up to a certain radius it is that of the void and then it is the relative one. How can I relate them? I'm trying to calculate the capacity of a spherical capacitor. The scheme looks like this: inside I...

This is the problem. If someone asks you this question, how would you solve it? I am finding it really tough to solve when the circuit gets a bit complex. It would be nice if you share what exactly you'll do to solve complex circuits such as this (the algorithm).

Equivalent capacitance before and after remains the same. Now the 10F capacitor (which was initially connected in parallel with 20F) would have 30 C charge. Hence an additional 20C must have been supplied to it. The only path which may supply the charge is through battery. However this leads...

Can I get some help in answering this questions? As I understand, for two electrodes: C=εA/d A = 0.012 m2 d = 0.001 m on the left and d = 0.002 m on the right. Thus the capacitance of each part is: Left: C = (εx0.012)/0.001 Right: C= (εx0.012)/0.002 Firstly, is this the right...

Hello, My understanding is that capacitance ##C## is an electrical property that is possessed by devices called capacitors whose basic construction involves two conductors separated by a dielectric. The two conductors involved in a capacitor don't need to be identical either in shape or size...

For my solution I'm skipping writing out all the vectors, I just want to see if I'm in the right way or totally off. Attempt at solution: Qenc = ∫ E(r)*e0 ds = ∫ E(r)*e0 *h* r*dtheta, we integrate from 0 to phi0. This will give us Q = E(r)*e0*h*r*phi0. Now we find V by integrating E from a to...

See attached image

I attached below my attempt to solve the question.

By combining the formula for the reactance of a capacitor with Ohm's Law for a capacitor, I can solve for angular frequency, and divide by 2π to find frequency. The resulting equation is: f = I/(2π VC) Using the given values, I end up with 5.2 kHz, instead of the correct answer of 5.2 MHz. I...

First of all I believe that capacitors 1, 2 and 3 are connected in series, because the charge on them must be equal so I combined them. After that, I suspect that the result of their combined capacitor (C123) is connected in parallel to C4 because the voltages on them are the same. After that...

I'm trying to obtain the free carrier concentration vs depth profile from the CV (capacitance-voltage) measurements of a normally-on HEMT with the expressions used for a Schottky barrier, but I´'m confused about how to extract the values for depth. I found in textbooks and articles that the...

I was not able to derive the charge on the capacitor. But then, I arbitrarily assumed ##\phi=B.A## (Dot product of Magnetic field and Area) Then, proceeding as follows, ##\phi=BA\cos(\omega_0 t)## ##\frac{d\phi}{dt}=−BA\omega_0\sin(\omega_0 t)## Now at ##t=0, \phi=BA\cos(0)=BA## Therefore...

$$C=K\varepsilon_0\frac{A}{d}=C=\frac{(8.85\times10^{-12})\times1\times 0.0254469}{0.01}=0.000022531F=22.531μF$$ 6V*(1-2.71828-t/0.019Ω*0.0000225307uF) time constants 6*(1-2.71828-1) = 6*(0.632) = 3.79 sec 6*(1-2.71828-2) = 6*(0.865) = 5.18 sec 6*(1-2.71828-3) = 6*(0.950) = 5.70 sec 6*(0.982)...

Hello, I have made a capacitive water level sensor. It is a parallel plate capacitor. While measuring the capacitance of my sensor, I measure 53 pF. I then leave it for couple of minutes, still conected to the meter, capacitance then rises to 54 pF. Capacitance is slowly increasing. Why is...

The circuit is shown. The explanation says "The total potential difference is 2V." "The total equivalent capacitance is C." Since there are 4 parallel capacitors, isn't the equivalent capacitance 4C and total potential difference 4V?

Summary: Two plates side by side, not parallel to each other. Hello everyone, Purpose of this capacitor is to detect changes in water level. It is constructed of a single copper plated pcb on which middle I have made a 1 mm of space separating now two copper plates on a single pcb. So, plates...

Question Part C Part D

a) Find Electric Field at any point in the dieletric in the terms of the parameters given Making a pillbox Gaussian surface with one end in the conductor where E = 0 and the other end in the dieletric we have that $$\oint D \cdot dS = \rho_s A \implies D = \rho_s \implies E = \frac{Q}{A...

The first part (which I believe I've done correctly) asks us to find the electric displacement everywhere. For this: $$\int D \cdot da = Q_{f,enc}$$ For a < r < b: $$D = \frac{Q}{4\pi r^2} \hat{r}$$ Otherwise, D = 0 When finding the capacitance, I'm unsure how to handle the r dependence. I...

Hello, In regards to this relay, TQ2SA-1.5V Panasonic 2 Form C AS Single side stable, 1.5VDC 2A DPDT NON-LATCHING SMD Relay https://www.mouser.com/ProductDetail/769-TQ2SA-1.5V PDF 1 of Relay PDF 2 of Relay (specifically pages 5-6) is attached at the bottom as a pdf file. I was previously told...

Hi all, I have mechanical background but I came across some electrical issues when I am doing my research. I bought (ams) pcap02 to measure capacitance behavior in parallel plate capacitors for certain material using a dielectric with 4.5 relative permittivity. As known, I used the upper plate...

Seems the physics books agree that there is no difference in capacitance whether an isolated sphere is solid or hollow. And the reason mentioned for that always sounds something like the following: "The reason that the capacitance C, and hence the charge Q, is not affected by whether or not the...

Hello! I've done tons of research on a problem and can't seem to figure something out. I'm looking at operating a photovoltaic PIN photodiode. Since it's operating in photovoltaic mode, it will produce a current when light hits it, and this will produce a forward voltage. I've researched...

Hello, the problem is better illustrated at the picture below. The capacitor is isolated, with an initial charge Q0. I understand that Q0 does not distribute along the plates homogeneously. How could it be solved with the equivalent parallel circuit?

I raise this question because at a fundamental level I still do not understand how a Capacitor works and how a circuit completes thru capacitor. The live electric tester screwdriver uses stray body capacitance to lit a neon when one end comes in contact with live wire and another with a human...

The capacitance C of a conductor is given to be a constant relationship between charge Q and potential V of the conductor given by Q = CV. But how can C be a constant? Because the potential of the conductor will not be a linear relationship of the charge that I add. THe more charge there is on...

A makeshift metal detector can be made if you have an accurate INDUCTANCE meter and a coil of a large diameter. Instead, I've got a capacitance meter, this one: http://www.pw-electronics.co.uk/DMM.pdf How can a little circuit be added (like a capacitor with a resistor in series or in parallel...

I) For the first part I used: ##V = - \int E ds = \int_a^c \frac{1}{4\pi\epsilon_0} Q /r^2 dr+ \int_c^{c+d} \frac{1}{k} \frac{1}{4\pi\epsilon_0} Q /r^2 dr + \int_{c+d}^b \frac{1}{4\pi\epsilon_0} Q /r^2 dr ## And by using ##C = Q/V## We get an answer which is somehow large for writing here...

The force of repulsion between two identical point charges when kept with a separation r in air is F. Half the gap between the two charges is filled by a dielectric slab of dielectric constant K=4. What is the new force of repulsion between the two charges? This is the question. Now if I solve...

according to http://230nsc1.phy-astr.gsu.edu/hbase/electric/capsph.html#c2 isolated spheres have capacitance but how can it be measured with an instrument?

Homework Statement I plotted a graph where Capacitance is at y-axis and Inverse Distance is at x-axis. It looks like a positive, increasing function. I am asked of a best fit, also an equation. But i am not sure whether to use quadratic or linear fit. I am also asked of what the slope...

Homework Statement Question: https://imgur.com/a/EmGDW87 Homework Equations Q =VC V = IR The Attempt at a Solution I don't understand how the capacitor C_2 is in parallel with R, which would dictate that they have the same p.d, but then again the circuit is in stead state and so no current...

I was reading The Feynman Lectures on physics http://www.feynmanlectures.caltech.edu/I_23.html chapter 23, section 4. In it he derives the equation for current when inductor, resistor and capacitor is connected in series with an alternating voltage source, he derives this equation:-...

I have a question on what happens to MOS capacitance Cgs+Cgd, when Vgs goes negative in the NMOS shown. I see that when Vgs goes negative, the channel is full of holes because of p- substrate, which means we see the Cox capacitance (without any other capacitance in series), but I am not sure if...

Homework Statement A 50 kW load operates from a 60 Hz 10 kV rms line with a power factor of 60% lagging. Determine the capacitance that must be placed in parallel with the load to achieve a 90% lagging power factor. The Attempt at a Solution For Z at 0.6pf S=P/pf = 50000/0.6 = 83333.33VA I =...

HiI was reading about capacitors and potential energy. But the equation seems counter to how i thought. For potential energy you have: U = Q^2 / 2C or U = CV^2 / 2 But doesn't this suggest you lose potential energy the more capacitance you have? Since in the first equation as C increases U...

I'm considering two identical spherical conductor each of radius ##a## and separated by a distance ##d##, and trying to figure out the capacitance of this configuration. My thoughts are that since capacitance is $$C=\frac {Q}{V}$$ and that the spherical conductors are equipotential surfaces...

Homework Statement 1. A 2.01 uFcapacitor that is initially uncharged is connected in series with a 6.51 kΩ resistor and an emf source with 74.6 V and negligible internal resistance. The circuit is completed at t = 0. a) Just after the circuit is completed, what is the rate at which electrical...

Homework Statement In the attached file.. The question asks about the charge and capacitance after being separated by twice the original separation. I also need to know if it is kept connected to the battery( spearted to twice the distance,too) , what would happen to both the charge and...

Homework Statement A charged isolated metal sphere of diameter d has a potential V relative to V = 0 at infinity. Calculate the energy density in the electric field near the surface of the sphere. State your answer in terms of the given variables, using ε0 if necessary.Homework Equations Since...

i have a drawing of a circuit that converts a signal in range [-5,5] V to a range [0,1.2]V . i wish to understand how it works.. i have basic knowledge of electricity as an undergraduate in general physics but a bit rusty , thus i am here looking for answers...

Homework Statement A capacitor is made up of a pair of square plates, each of side length L, that are very nearly parallel (such that θ is very small) and separated by a distance D. The plates make an angle, θ, with one another. The capacitor may be thought of as being comprised of many...

Homework Statement A spherical capacitor has internal radius ##a## and external radius ##b##. At time ##t = 0##, the charge of the capacitor is ##Q_0## Then the two shells are connected by a resistor in the radial direction of resistance ##R##. Find the Poynting vector and the energy...

Homework Statement Between the plates of parallel plate condenser having charge Q,a plate of thickness t1 and dielectric constant k1 is placed.In the rest of the space,there is another plate of thickness t2 and dielectric constant K2.The potential difference across the condenser will be...

Hello, Could someone help me find a general derivation of the formula for addition of capacitance of conductors? I'm hoping to find something that could be applied to a general assortment of conductors, not just parallel plate capacitors. I look forward to your response, Pete

When analyzing the transient development of a circuit containing a DC voltage source, capacitor and resistor in parallel, how might one explain the fact that 1. the voltage drop across the resistor changes with that of the capacitor. 2. The first loop containing the capacitor and DC source seem...

The lower plate of a parallel plate capacitor is supported on a rigid rod.The upper plate is suspended from one end of a balance.The two plates are joined together by a thin wire and subsequently disconnected.The balance is then counterpoised.Now a voltage V= 5000V is applied between the...

Homework Statement Five plates with same area are placed as in figure. Distance between any 2 consecutive plates is d. Find equivalent capacitance(ab). (Note-Answer is given as 5C/3, in terms of C so I suppose C is capacitance of a +ve and -ve plate separated by d). The lower letter is A, it is...