Capacitor Definition and 1000 Threads

So some time ago I got a bunch of electrolytic caps from a friend of mine who works at a local university experimental laboratory, the caps have been in good storage (temperature etc) they were sitting some while in my room and now I finally decided to see whether they are still any good. Some...

Homework Statement A capacitor consists of two large metal disks placed a distance ##s## apart. The radius of each disk is R ## (R \gg s)## and the thickness of each disk is ##t##. The disk on the left has a net charge of ##+Q## and the disk on the right has a net charge of ##-Q##. Calculate...

Homework Statement This is not a homework problem, I'm working through griffiths Electrodynamics on my own. Homework Equations when there is an emf source, since electrosatic fields integrate to zero around a loop The Attempt at a Solution The solution claims that since the integral of f...

Hi all, I'm trying to wrap my head around the physics behind the current that initial flows when a voltage step is applied across a capacitor. Namely, why does a large current initially flow into a parallel plate capacitor, but a large initial current does not flow if the capacitor is replaced...

1. Two identical flat plate capacitors are inserted in each other. First, none of the plates was charged, but then they have been connected to sources of current, keeping the constant voltage ## V_1 ## and ##V_2 ##. Find the potential difference between inner plates, which are kept at the...

Homework Statement An isolated parallel-plate capacitor of area ##A_1## with an air gap of length ##s_1## is charged up to a potential difference ##\Delta V_1## A second parallel-plate capacitor, initially uncharged, has an area ##A_2## and a gap of length ##s_2## filled with plastic whose...

hi everyone! i am not into physics, but need it now,i am a programmer workin on an IOT project...so kinda need help. i want to use a capacitor to see what passed between two plates...knowing, it is the change in dielectric after certain intervals...how do i measure the change at the other...

Homework Statement I have a material placed between parallel plates depleted of free electrons and contain negative ions. What would happen to the charge stored across the plates? Would it still be similar to placing a capacitor with a di-electric constant between them? Homework Equations Q=CV...

So I am stumped by why these capacitors are there, to my understanding the capacitor C3 acts as a low pass filter but then I don't quite understand the purpose of C1 and C2 as indicated on the picture.

Homework Statement There is a capacitor (llenght ##L##) made of a conductor (cylinder of radius ##R_1##) and a cylindrical surface (radius ##R_2##). It is charged with a potential ##V_0##, then it is isolated. (There is vacuum between ##R_1## and ##R_2##) Now we insert a cylindrical...

Homework Statement Hi mates, I have problems solving the third part of this exercise, I've already done all the previous calculations. Given the following circuit, where the switch S is open, the power supply = 50 volts and: The initial charge in the C capacitor: QC = 0 coulombs The initial...

Hi! Could you please help me with the queries below? Thanks a lot. Question 1: My question is about the field outside the plates of parallel plate capacitor. It is said that the field(s) between positively and negatively charged plates gets added up but the field(s) outside the plates gets...

I already have made the thread "Can a defective DRC [Dual Run Capacitor] on a heat pump cause the fan motor to go bad?" Earlier today I told my father how a defective DRC on my heat pump caused the run winding on my fan motor to burn up. My father asked me if a defective fan motor can cause a...

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...

Homework Statement Homework Equations Z = √(XC2 + XL2) XL = 2πƒL XC = 1 / 2πƒC I = V/Z The Attempt at a Solution First off, thank you for all of the help this semester. I'm sure you'll be seeing questions from me in the spring also. Here is how I'm thinking about this problem: 1. Using the...

Hello, sorry about my english it's not my mother tongue. I hope this is the right section to place this. 1. Homework Statement A cylindrical capacitor is placed in the sea so that when a wave comes (the water goes up), the water becomes the capacitors dielectric, when the wave has passed (the...

Homework Statement https://imgur.com/vQRoMjZ Homework EquationsThe Attempt at a Solution I believe that the inductor does negative work on the charges via the electric field (by way of induced EMF). I am unsure about how the capacitor would be doing positive work, though. Can anyone help steer...

In an LC circuit, the capacitor that is initially charged to a finite value starts to discharge cross the inductor, initially the current increases and the inductor opposes it, but as the current is supplied against the back emf, due to the discharging of the capacitor, won't it reduce the value...

1. We've been given a spherical capacitor with radius of 1 cm for inside electrode and 2 cm for outside electrode. Voltage between electrodes is 360 V and the task is to find largest and smalles electric field strength in capacitor.2. I'm not sure how voltage given in capacitor works and how to...

I work for a company that locates underground cables and pipes. We apply an AC signal to the underground facility and to be able to detect the location. Take the simplified drawing above. Two transformers grounded with a buried electrical cable. We use a transmitter and connect it to one...

Hello friends... I'll jump right into the deal here.. I pranked a friend by putting a raspberry pi into a yoda head like the one on his desk. There's an intro video: and the prank itself: if you are intrigued. Everything in the head runs off 3 AAA batteries. 1 raspberry pi zero w, 1 small...

Homework Statement In the circuit shown, C1= 1 microfarad, C2=3 microfarad, in steady state, the energy stored in these capacitors are? Homework Equations Kirchoff's laws, E=0.5CV^2, V=IR The Attempt at a Solution At steady state, no current passes through the capacitors, so current is...

Homework Statement So I am solving a 555 timer questions, and there is a resistor that is grounded on both terminals at one point. My question is what does this do to the resistor? Homework Equations Vc(t) = A + Be^(-t/(R*C)) The Attempt at a Solution I know that if you ground one terminal...

So the work done when charging up a capacitor is ##dW=VdQ## However, when we add a charge ##dQ## to the capacitor, ##V## also changes accordingly, so I was wondering why the work done wasn't written as ##dW=VdQ+QdV## (one that also takes into account t he change in ##V##). Thanks in advance.

Homework Statement A Metallic sphere with radius r=10cm is surrounded by a spherical metallic shell of radius 2r=20cm. The space exist between the two is vacuum. An amount of k=0.01 mol of radioactive 242Cm is strayed uniformly on the sphere, the radioactive isotope emit alpha particles which...

Homework Statement Homework Equations 3. The Attempt at a Solution [/B] Currently stuck on the question relating to the value of capacitance across X1/Q1 to reduce the voltage to 1 LSB I have calculated the voltage of the 1LSB to be 0.8507 mV ADC Range/Resolution 3.3V/2^12 I have...

Homework Statement So I need to find the equivalent resistance for the following RC circuit to calculate the time constant, but I got stuck in terms of finding out the equivalent resistance. Homework Equations V = IR The Attempt at a Solution So the thing I am not sure on is how do you...

Homework Statement A capacitor of capacitance 10 uF is raised to a potential difference of 150V. After disconnecting from the battery, it is connected to a capacitor of capacitance 5 uF. Find the energy of the system. Homework Equations Energy supposed to be equal in the first case and second...

Homework Statement We have a circuit with a battery, two resistors, a switch and a capacitor. We assume that the battery has a switch so that we can choose whether it should be a voltage source for the circuit. a) At time t = 0, we put on a voltage Vs over the battery in the circuit. What is...

Need to come up with specifications for a capacitor that can hold 20,000 or more amps How many joules or watts or how much energy can this theoretical capacitor hold how many farads, what would the current be and how many volts could it tolerate, how to increase volt tolerance. how to increase...

Homework Statement The current through a 100 microfarad is i(t) = 50 sin(120*pi*t) mA Calculate the voltage across it at t = 1 ms. Consider zero initial voltage. Homework Equations v(t) = (1/c) integral of i(t) from t = 0 to t = t The Attempt at a Solution Am getting v(t) = - 1.326 (...

Homework Statement I have attached a problem from within the chapter of my book. I have a question regarding my highlighted part. My question: Is the reason they are saying E= -Q/(ε0A) because they defined the positive "s" axis to the right? and since E is pointing from right to left we say...

Hi, today in lecture, we discussed the work done on inserting a dielectric between a capacitor. Two cases of this example: One case, where the battery is disconnected so that the charge stays constant. Other case where the battery stays connected so voltage is constant. I am confused on...

Homework Statement Working through Purcell (among others) as fun applied math/math modeling refresher. But, I have struggled all week in establishing from first principles that the potential/field/distribution for a configuration of two capacitive disks of radius 1 and separation s along the...

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...

Say there are two parallel plates separated by a small fixed distance d and charged +q, -q. The force attracting the plates is F. If a solid block of dielectric (dielectric constant k) is introduced between the plates, will the force of attraction be different from F. My answer: The electric...

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...

Homework Statement A negative charge of mass m enters into the field between two deflecting parallel plates with length 'l' separated by distance 'd' with a velocity 'v'.Assuming electric field to be uniform,find the maximum charge so that it will not hit a plate Homework Equations Kinematic...

Why is the electric potential of an electron in a capacitor measured from the negative plate and not the positive plate here? This is from Liboff Introductory quantum mechanics 1st(current is 4th) edition: I don't understand why the distance z is measured from the bottom plate if the...

Homework Statement If you put a capacitor in some circuit, why exactly do the conductors that form the capacitor have equal and opposite charge? This seems to be assumed in many cases. Homework Equations Is it possible for the conductors to have different magnitude of charge?

Is it possible to make a capacitor with a dielectric not of the same size with its conducting plates?

If a capacitor is being discharged and the electric field is varying with time producing the displacement currents, wouldn't it be possible to align a time-varying external magnetic field with the magnetic field produced by the displacement currents to increase the discharge rate? Or the...

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 A parallel plate capacitor (capacitance C) is charged with a battery of emf V volts. A dielectric slab of dielectric constant K is placed between the plates to fully occupy the space. The battery remains connected. What are the changes in-1)C 2)Q (charge on capacitor) 3)E(E...

Homework Statement Two capacitors of 1 and 2 micro-farad respectively are each charged by being connected across a 5 V battery. They are disconnected from the battery and then connected to each other with resistive wires so that plates of opposite charge are connected together. What will be the...

Homework Statement A constant potential is maintained across a parallel plate capacitor. A dielectric slab is slowly inserted between the plates (width of slab=distance between the plates). What will the direction of force applied by capacitor on dielectric be? Homework Equations All relevant...

Homework Statement [/B] After how many time constants is the stored energy of a discharged capacitor one-fourth its initial value? Homework Equations [/B] (1) U = Q2/2C (2) U = Qmaxε/2 (3) q(t) = Qie-t/RC The Attempt at a Solution The solution can be correctly attained using the first...

I was recently solving a problem that involved a circuit with a capacitor that was connected to a battery at one end(the second plate just had a wire which didnt lead anywhere). In the solutions it said that this capacitor cannot have any charge since there is no path for the current to flow...

Homework Statement I calculated the capacitance of two concentric conducting spherical shells of radii a and b (a<b) when the inner shell has charge Q and outer has charge -Q correctly by using C=Q/(V(i)-V(o)), the problem I have is described below in "attempt at a solution" Homework...

Homework Statement I was reading through the principle of a capacitor and I am unable to understand one of the statements. My textbook says the following- Consider an insulated metal plate A. Let it be connected to a voltage source and charged to a maximum. Now an uncharged plate B is brought...