Capacitors Definition and 884 Threads

Hello, what is the consensus on using super capacitors to power a 500w electric bike motor. cheap and innovative alternative to li-po batteries or explosion between thighs waiting to happen? the plan is to create something like this: i will use a 24V motor...

Homework Statement Theses questions have been modified to solve my own inquiries. The originals can be found in the attached file. A parallel plate capacitor has area A = 1 cm2, a plate separation of d = 0.01m, and is filled with air.(a) If the breakdown field is E0 = 3 × 106V/m, calculate...

So I understand that a capacitor consists of 2 plates separated by a distance which creates a potential difference between the plates. But I was confused, when watching this physics video it seemed to be saying that once the capacitor was fully charged, the plate closest to the positive terminal...

Homework Statement The problem I encountered goes like this: A 10cm long thin glass rod uniformly charged to 10nC and a 10cm long thin plastic rod uniformly charged to -10nC are placed side by side 4cm apart. What are the electric field strengths E1 to E3 at distances 1cm, 2cm, and 3cm from the...

Homework Statement C1=C2=C3=C No internal resistance. We wait for a while and the put a dielectric material in C3. Then after waiting again we remove the voltage source and after that we take this material out. How will the voltages on the capacitor be affected? Homework Equations CV=Q The...

Hi everyone. I am doing some research about Cockcroft Walton Accelerators, because I need to be able to explain them to others as a part of a project. However, in order to understand the Cockcroft Walton Accelerator, I need to be able to understand the Cockcroft Walton Generator first. I have...

Homework Statement One capacitor with a capacity of 6μF and another with a capacity of 12μF are charged by being connected in a series to a voltage source with an electrive force of 660V. After that, we disconnect the capacitors from the source and connect them to each other. What is the charge...

Homework Statement First, we connect a capacitor to a voltage source with an electric force of 60V. After that we put another capacitor with a capacity of 0.01nF instead of the voltage source. As a result, the voltage on the first capacitor is down to 40V. 1. What is the voltage on the second...

consider that we have two dielectrics inside a capacitor as shown in the picture, let0s consider also that Q is the charge of the capacitor and d the distance between the two plates , the first dielectric occupy a surface of S/3 with a dielectric constant of er1 and the second a surface of 2S/3...

Homework Statement A capacitor of 5μF is charged to 24V and another capacitor of capacitance 6μF is charged to 12V , the positive plate of first capacitor is now connected to negative plate of second and vice versa, find new charges on the capacitor Homework EquationsThe Attempt at a Solution...

I understand algebraically that when capacitors are in series, the total capacitance is less than any individual capacitance, but I do not understand this intuitively. How can this be possible? Shouldn't more capacitors equal more capacitance?

Consider a parallel plate capacitor formed by two plates of length ##L## and width ##d##, separated by a distance ##e##. There is a vacuum in between the plates. Let's note the capacitance of this arrangement ##C_0##. I insert a conducting plate of length ##l=L/2##, with ##D##, and thickness...

1.when a charged capacitor is connected to an uncharged capacitor will they attain the same voltage ?the initial and final energy are different why is this so?2.q=CV,U=c*v*v/23. I tried to equate the initial and final energy of system of capacitors but the answer does not match.what is the...

This is what I have and I was wondering where C2 might go if I make apply the hybrid pi model on this circuit. I know that all the DC Voltages should be shorted if I were to make use of an equivalent circuit, so that in the hybrid pi model R1 should be in the input and R3 in the output. But what...

Homework Statement Are ALL parallel plate capacitors linear? Homework Equations D = permittivity * E The Attempt at a Solution Capacitance is linear if permittivity is constant. Is there a case where a parallel plate capacitor is not linear?

Homework Statement Some cell walls in the human body have a layer of negative charge on the inside surface. Suppose that the surface charge densities are ##±0.50 \times 10^{-3} C/m^2## , the cell wall is ##5.0 \times 10^{-9} m## thick, and the cell wall material has a dielectric constant of...

Homework Statement I'm just really lost on this topic and honestly don't have too much of an idea. (a) Using Kirchoff's loop rule, find the differential equation satisfied by the charge q(t). (b) Verify that q(t) = q_max e^-(a/t) cos(ωt) satisfies the differential equation for particular...

I'm trying to understand the difference between these two when it comes to measuring the amount of time they take. As of right now, my current understanding is that pole relaxation is based on the amount of time that it takes for polarization of the charges to go back to its relaxed state. For...

Homework Statement Capacitors C1 = 6.97 uF and C2 = 1.54 uF are charged as a parallel combination across a 281 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. A)...

Homework Statement I want to find the charge and potential drop across each capacitor Homework EquationsThe Attempt at a Solution I know both the capacitors are in series and hence have the same charge on them. However I don't know how to calculate the potential drop across the capacitors...

As distance between two capacitor plates decreases, capacitance increases - given that the dielectric and area of the capacitor plates remain the same. So, why does this occur?

I have recently come across a datasheet for a buck converter regulator that uses the terms "c code" and "No." for certain capacitors but when going to the manufacturer datasheets for these capacitors they make no reference to any "c code" or one single number for a capacitor. If anyone could...

I have a hard time comprehending excess charge in capacitor plates. Let's say we have two identical capacitor and we charged them to identical amount of charge. Next we connect them in series by opposite sign electrodes and we get double the voltage on the open ends. Now a single capacitor has...

Homework Statement I would like to know how to calculate the total capacity of the capacity network displayed in the uploaded picture. I know how to calculate the total capacity if the capacity are in parallel or in series, but I am confused by the capacity Nr 6. I know how to calculate the...

If a capacitor is charged to 10V where the negative side is connected to ground (0V), when the capacitor is disconnected from the power supply on both the positive and negative sides; 1) Will the negative side of the capacitor still be 0V relative to the ground it was just connected to? 2) Say...

Homework Statement For the curcuit shown in figure,which of the following statement is true? A)with S1 closed, V1=15V, V2=20V B)with S3 closed, V1=V2=25V C)with S1 and S2 closed, V1=V2=0 D)with S1 and S3 closed, V1=30V, V2=20V Homework Equations ▪Q=CV, where Q and V are the charge and...

Homework Statement Two capacitors C1 and C2 are charged to 120V and 200V respectively.It is found that on connecting them together the potential on each one of them can be made zero.Then, A)3C1=5C2 B)3C1 + 5C2=0 C)9C1=4C2 D)5C1=3C2 Homework Equations Q=CV Q-charge on capacitor C-capacitance...

Homework Statement I have the circuit above. When I have the switch at A, the capacitor C1 is charging at 100μF is at 10V. I then discharge the capacitor by connecting the switch to B. I was asked to calculate the time constant. I thought the capacitors were in parallel but according to...

How can I calculate the capacitor needed for my wave energy collector? I have have build a wave energy collector. It consists of multiple coils in series with magnets moving up and down, following the waves underneath the unit. My multi-meter measures anywhere between 60 and 250 milli volts...

Hello there, I was wondering if anyone wouldn't mind helping clarify what is occurring with a charged capacitor for me. I understand that in a charged capacitor one conducting plate is negatively charged and one is positively charged due to the distribution or rearrangement of electrons. There...

Long story short, on single-phase capacitor motors, large values of capacitance are used for starting and much smaller values are used for running. Yet it would seem that the amount of electrical phase shift needed is dictated and fixed by the physical relationship between the main and auxiliary...

This is a question from an a level textbook. The R starts at 8k ohms (thought its not relevant) Switch S is closed - C fully charges up. Question:Switch S is opened. Explain why the current decreases and REVERSES direction in the ammeter. This is what I think. The decrease in current is...

Homework Statement I am going over problems for exam study - here is the question with my submitted solution. Anything helps, just trying to correct mistakes so I can study the problems. Two capacitors C=3mF, C=2mF are initially discharged. They are connected in series and then the two ends...

The text in the paper says that C1 has Vout/N-1 = Vout/6, C2 has 2*Vout/6 and so on... Can someone please explain how? Source : Liao, Zitao, Yutian Lei, and Robert CN Pilawa-Podgurski. "A GaN-based flying-capacitor multilevel boost converter for high step-up conversion." Energy Conversion...

Homework Statement Homework Equations C = Q/V The Attempt at a Solution I understand that capacitors in parallel have the same voltage, but wouldn't they be in series after the switch is flipped, since no current goes to the left most portion of the circuit.

Homework Statement The plates of a parallel-plate capacitor are maintained with constant voltage by a battery as they are pulled apart. During this process, the amount of charge must... (decrease , increase , remains the same) Homework Equations C=Q/V C=E0(Area/Distance) The Attempt at a...

Homework Statement .50uf capacitor is charged connecting it to a 6.0v battery then discharged through 100k ohm resistor. . Question: Estimate the resistance of the resistor that you would use in place of the 100k ohm resistor if the discharge is to be 99% completed within about 5 secs...

Homework Statement In my lab, we are studying the efficiency of a simple DC motor. In order to do this, we related the initial potential energy of the capacitor to the final potential energy of a mass (which remained constant for all three capacitors) that the motor lifted. I was instructed...

Homework Statement 2 large plates are separated by a distance d and a space charge of uniform charge density p is placed between them and a potential difference V is applied across the plates. Find the electric field stength at a distance x fromt the positive plate The answer is -V/d...

My book says "the magnitude of charge on all plates in a series connection is the same." It then says "potential differences of the individual capacitors are not the same unless their individual capacitances are the same." If the plates were all the same size, given that they all have equal...

Homework Statement Two parallel-plate capacitors have the same plate area. Capacitor 1 has a plate separation twice that of capacitor 2, and the quantity of charge you place on capacitor 1 is six times the quantity you place on capacitor 2. How do the potential differences across each of the...

This is a general question, not a homework question, and @berkeman said I should post it in the EE forum... I'm trying to get a better understanding of the relationship of dielectric constant (relative permitivity) to dielectric strength (breakdown voltage).I want to know what happens when you...

Homework Statement Hello everyone. The problem is related to these two capacitor connections: In the enunciate it is said that these two are equivalent and it is requested to prove that: C1=(CxCy+CyCz+CzCx)/Cx C2=(CxCy+CyCz+CzCx)/Cy C1=(CxCy+CyCz+CzCx)/Cz Homework Equations C=Q/Vab...

Homework Statement [/B] If the 2 charged capacitors are reconnected in parallel with plates of opposite polarity together then ? is common potential. In this condition how charge is conserved and same potential is maintainedHomework Equations [/B] Net charge Q=C1V1-C2V2 Where C1V1=q1 and...

Homework Statement Homework Equations 3. The Attempt at a Solution [/B] First i found the voltage ##U_{13}=\frac{E(R2+R3)}{R1+R2+R3}=50V## Then i figured that the charge on 1 and 2 is equal since the voltage across is the same right? ##Q1=Q2=U_{13}\frac{C1C2}{C1+C2}=80mC## and...

Where does the voltage drop of a capacitor happen? My answer would be that It produces an electric field the opposes the field of the battery along the wires. So it is continuous lose to the capacitor which stores this energy in it. Another question related to this, When a positive charge hits...

Hello! I found how to calculate here: http://liionbms.com/php/precharge.php But the problem is, that when I used online calculator, it gives me that with resistance 531, my charging time to 288V will be about 2.3 seconds instead 5 seconds, that I need. Online calculator here...

I have spent hours on the web and in libraries to obtain a general and careful approach to the notion of capacitance, without success. Please, read carefully the question: I already know the usual blabla about capacitance. Also, I appologize in advance for the length of this question. I...

Homework Statement I am given the following circuit: and asked to solve for v(t) and i(t) Homework EquationsThe Attempt at a Solution If this is right, I don't know where to go from here.

Homework Statement I am practicing these types of problems, for example: and I am asked to find i(t) in this case, and it is in steady state. I really need someone to walk me through these types of problems, how do I get them started. Homework EquationsThe Attempt at a Solution I am really...