Capacitors Definition and 884 Threads

Homework Statement Wire up a circuit with C3 in parallel with C1 and C2 in series. You will need to measure the current arriving at the capacitors (before they are fully charged) and the voltage across capacitor C2. The Attempt at a Solution I'm not sure if I'm measuring the current before...

I'm impressed by the specifications of the newest capacitors. They are sold in the form factor of a D cell battery for at little as $8 each. I have no question. I'm just amazed at how fast that technology is improving. It may be time to consider applications for capacitors that we pooh-poohed...

I learned about surface charge feedback theory in electrical circuits a few months ago and it has been extremely helpful for me to intuitively understand many concepts in electrical circuit analysis including conservative and non-conservative fields. I initially referred the paper written by...

Homework Statement A parallel plate capacitor was lowered into water in a horizontal position, with water filling up the gap between the plates (gap d=1.0mm). Then, a constant voltage V=200volt is applied to the capacitor. Find the increment of pressure in the water between the gap. Homework...

Homework Statement Show the the induced charge density on a dielectric placed inside a capacitor is given by $$\frac{k-1}{k}\sigma$$ where ##\sigma## is the charge density of the capacitor plates and ##k## is the dielectric constant. Homework Equations $$E=\frac{E_0}{k}$$ The Attempt at a...

Homework Statement What charges will flow after shorting of the switch (Sw) in the circuit below through sections 1 and 2 in the direction indicated by the arrows? Homework Equations Kirchoff's laws The Attempt at a Solution Initially, both capacitors will have a charge of...

Homework Statement The Attempt at a Solution Now, they're in series, so I found the equivalent capacitance to be about 0.57 microFarad. And I have technically gotten the correct answer according to the back of the text. The question in the text clearly asks for the charge on each...

Why do capacitors need dielectrics (insulators) in between the two plates(conductors)?What if there is no dielectric in capacitors ?Function of a capacitor is " a capacitor stores energy in the form of an electrostatic field between its plates" Let's say there is a conductor is between them...

1)The charge on the positive plate of a capacitor is called the charge on the capacitor.Why? I think it is just a convention. 2)There is a passage in my textbook. Any conducting object that carries a charge is characterized by an electric potential that is constant everywhere on and within that...

Homework Statement What is the entropy change of the universe as a result of the following processes: (a) a 1μF capacitor is connected to a 100V electrochemical cell at 0°C, (b) the same capacitor after being charged to 100V is discharged through a resistor kept at 0°C? Homework Equations...

A sheet of gold foil (negligible thickness) is placed between the plates of a capacitor and has the same area as each of the plates. The foil is parallel to the plates, at a position 1/2 of the way from one to the other. Before the foil is inserted, the capacitance is 7.9μF. What is the...

Problem: When a dielectric slab is inserted between the plates of one of the two identical capacitors in Fig. 25-23, do the following properties of that capacitor increase, decrease, or remain the same: (a) capacitance, (b) charge, (c) potential difference (d) How about the same properties of...

In an example from my textbook, two capacitors are fully charged and then disconnected from the battery. (The full text is on the bottom of the thread). Initially, the positive charge is on top, negative on the bottom. How did this occur? This is the part that I don't understand...

Two capacitors (lets call them C1 and C2) in series are connected to a voltage source and charged. While still connected to the source one of them is filled with a dielectric (lets say C2 is filled). I know the charge on C2 will change by a factor of K because the source keeps the potential...

Homework Statement My lecture notes say that no current flows through capacitors as the dielectric material is a poor conductor. It goes on to say that the capacitor appears as an open circuit to a DC voltage source. It then says that charge will accumulate on the plates with an equal amount of...

I just had a test, and I'm wondering how to do one of the free responses on it. The first couple parts, which I'll omit, were pretty simple, but I got kind of lost toward the end. Two Capacitors (C1=10microF C2=40microF) are connected in parallel to a 10V battery. The capacitors are then...

Homework Statement [/B] I have come upon a number of problems where there are two or three different dialectrics inside a capacitor. according to the solutions manual I can often treat the dialectrics as capacitors in series or parallel. My question is why can you treat them as capacitors...

Hey guys, I know I have left some topics unanswered. I'm working on reading more about electricity to improve my understanding. Thank you for having helped me in earlier topics, I have certainly begun to comprehend a lot more. Now, right to the question. So I got a capacitor being charged up by...

Homework Statement In the given DC circuit, while switches S1,S2 are open, conductor C1 is charged with Q10, and conductor C2 is not charged. After the switch S1 is closed, through conductors flows the amount of charge q1=40µC. After the switch S2 is closed, through conductors flows the amount...

Homework Statement Hi I have been told that the question below might be similar to potential university interview questions for physics/electronic engineering. In relation to this circuit diagram: http://forum.allaboutcircuits.com/attachments/diagram-ac-diode-capacitor-pd-question-png.90713/...

Hello everyone, I have drawn a picture of my confusion, I think it says it all: Now to add some text: so we charge two capacitors C1 and C2 to a voltage V. Now we have two charged capacitors. We now connect -Q1 to +Q2 and nothing else (the other two legs are floating). From my basic...

Homework Statement (a) Calculate the Electric displacement of parallel plate capacitor of with a thickness d (in z), and length L (in x), and a width W (in y). Within the capacitor is a dielectric oil with a dielectric constant –εr , and the charge on the plates is ± q. (b) Using the...

I have been studying capacitors and inductors recently and I have seen this video. I have a few questions about capacitors and inductors. Capacitors: 1.how do capacitors discharge? 2. What happens when you apply direct current through a capacitor? 3.Do capacitors only allow certain...

The question is based on the image below but is not the same. The question is as follows: Assume the capacitor is charged, so that there is a charge q on the top plate and a charge -q on the bottom plate. Determine the magnitude of the potential difference across the k2 region, answering in...

First in Circuit A: I hook up a battery with a voltage of V up to a capacitor C1. Once C1 is fully charged it has 6+ on its positive plate and 6- on the negative plate. Given it's fully charged, the +terminal of the battery and the +plate are in electrostatic equilibrium. Since they are both in...

Homework Statement Hi everyone. I m just studying capacitors but I have problems with gauss law. In one exercise it says that we have a sphere(cavity) of radius r, with a charge q placed inside the sphere of it. Wie have to find the electric field inside and outside sphere. The solution says...

Homework Statement A capacitor has a capacitance of 5μF. If its fully charged from a 12V battery; i) What will its charge on its plates at the end of the process ii) The combined capacitance if the capacitor is connected in parallel with another 10μF capacitor iii) The combined capacitance if...

Recently I have obtained and have been maintain several pinball machines. On one of them, the 6v winding on the transformer is producing 7.3V. I am also having dificlty keeping lamps in this machine, they burn out faster (a week or so) then I think they should. My idea is that the 20% over...

1. So my teacher gave us examples of how to solve capacitor problems. I know how to solve the problem but I don't this problem's particular "formation" of parallel capacitors. In this problem, my teacher says C3 and C4 are parallel but when I did the problem, I assumed it was series. Can anyone...

Hi guys, I was tutoring some students and I was explaining them how to calculate the capacitance between two parallels planes. They made me some questions and actually I am not quite sure about my answers! I started by showing them how to calculate the electric field generated by a single...

This question was taken from the public examination in my country/region. The answer from the marking scheme is, only statement 1 is correct and the others are wrong. Can anyone explain why the other statements are wrong? 1. Homework Statement The following components are connected in series...

Homework Statement Here's the question as it was given. we should find the effective capacitance across A and B, Homework Equations ##C_p = C_1 +C_2+...## ##\frac{1}{C_s} = \frac{1}{C_1} +\frac{1}{C_2} +...## The Attempt at a Solution Looking at the diagram i thought The capacitance should...

Homework Statement (See image) 2. Homework Equations C=Q/V The Attempt at a Solution Part a took a while but I now understand that the electrons gather on the right plate of the 2μF capacitor and on the right plate of the 4μF capacitor. This imparts a negative charge of 133μC on each...

I have charged two capacitors in series with a 100V cell such that now, there are electrons on the inside plate of one and the outside plate of the other, bunched up so that they incur a negative charge on each capacitor of 133micro coulombs. Now, they are just connected to one another with a...

In my textbook it is written that Electric charge on plates of capacitors (without dielectric ) is Q=CV And when dielectric is inserted in the space between plates of capacitors .charge Q remains the same whereas values of C and V change. i.e Q=C'V' is it correct?

Homework Statement All information is given in the picture posted Homework Equations V=IR , Q=CV The Attempt at a Solution What I don't understand is , when the capacitors are initially uncharged , they should just be treated as wires , if this is the case , then the entire circuit is...

Hello, So in a series capacitor arrangement, I understand that the charge on each capacitor is the same. I also appreciate that you can replace the array with an effective capacitor. What I am not in agreement with is the fact that the charge on this effective capacitor is the same as the...

When answering a related question on physics forum, I found something I seemed to be confused about: Suppose we have a battery connected in series to a capacitor with no charge. A capacitor with no charge on it acts like an open circuit. I know what happens next: the battery charges the...

Homework Statement When a capacitor is discharged, where does the charge "go back to"? Explain. Homework EquationsThe Attempt at a Solution I know that the charge goes from positive to negative, but I do not know how to explain this.

suppose 2 capacitors C1, C2 connected in series with battery V, let charge in circuit be Q, since they are connected in series so each capacitor will have Q also, suppose we disconnected them from the battery and reconnected them again in series (without connecting voltage source or Earth with...

Homework Statement A 10nF and 20nF capacitor is independently charged to respectively 40V and 50V. The positive sides of the two capacitors are connected, and a 1kΩ resistor is connected across the negative terminals. Find equations for total voltage VT(t) across the resistor and voltages...

Homework Statement Homework Equations Q = CV The Attempt at a Solution C1 charges to Q0 = C1V = (8 x 10^-6 F)(12 V) = 9.6 x10^-5 C when the switch is flipped the total charge is the same (Q0) but it is spread over the two capacitors which are now in parallel. so Q1 + Q2 = Q0 so C1V1 +...

Homework Statement A 12V DC supply is connected in series to 2 capacitors, of 12 and 4 micro farads. A switch is in series also. The diagram shows the capacitors above the supply and the larger capacitance capacitor to the left. The names of the plates of the capacitors from left to right are...

Homework Statement Two capacitors, C1 = 2910 pF and C2 = 2230 pF, are connected in series to a 12.0 V battery. The capacitors are later disconnected from the battery and connected directly to each other, positive plate to positive plate, and negative plate to negative plate. What then will be...

In an example in my book, the author poses the following question: Given two large plates at a distance d from each other with arbitrary charges Q' and Q" (with Q' on the bottom plate and Q" on the top plate), how are the charges distributed on the plates? The author lists the following...

I am working on identifying an issue with blown fuses in a subwoofer for a friend. The subwoofer is a Velodyne SPL-R10. The subwoofer has blown several fuses and I am attempting to locate any loose connections that may have caused a short. I am very inexperienced with complex circuits such as...

Homework Statement Capacitors ## C_1 = 4 \mu F## and ##C_2 = 2 \mu F## are charged as a series combination across a ## 100V## 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...

Homework Statement A 25 and a 40 capacitor are charged by being connected across separate V batteries. The capacitors are then disconnected from their batteries and connected to each other, with each negative plate connected to the other positive plate. What is the final charge on each...

Hello, Capacitor When a capacitor is connected to a voltage source, electrons will move from one plate and accumulate in the other in accordance to Q=CV. Due to the imbalance of charges (positive and negative ions) between the plates, an electric field exists that flow in the direction of the...

Hopefully no one minds that I post a couple questions in a row as long as I'm following the rules: 1. Homework Statement Two infinite parallel plates labelled W and X are separated by 5.2 cm. The electric potential between the plates is 150 V. An electron starts from rest at time tW and...