Capacitor Definition and 1000 Threads

  1. S

    Engineering Finding the component values of a RLC circuit

    What methods could I utilise to find the individual values of the components - resistor, inductor and capacitor - of a series RLC circuit using an oscilloscope, signal generator and 10 ohm resistor. Where each component can be isolated in order to find the voltage etc. I've already found the...
  2. S

    Impact speed of an electron in a parallel plate capacitor

    Homework Statement The electric field strength is 2.50×104 N/C inside a parallel-plate capacitor with a 1.20 mm spacing. An electron is released from rest at the negative plate. What is the electron's speed when it reaches the positive plate? Homework Equations F = eE = ma vf2 = vi2 + 2ad...
  3. STEMucator

    Output waveforms with a clamped capacitor

    Homework Statement For the circuits shown, each utilizing an ideal diode (or diodes), sketch the output for the input shown. Label the most positive and most negative output levels. Assume ##CR > T##. The input waveform is given by: I have re-drawn all of the circuits in my solution, which...
  4. Clear Mind

    Effects of emitter capacitor in the BJT CE amplifiers

    Suppose to have a BJT Common Emitter amplifier like the one below: Now, if we send a signal ##V_{in}## with a frequency belonging to the midband frequency interval, we can consider ##C_1, C_2,## and ##C_E## as short circuit. Questions are: 1) What is the effect of ##C_E## (excluding its role...
  5. samjohnny

    Solving Homework Equations: The Attached Voltage Across Capacitor

    Homework Statement Attached Homework Equations The one given in the hint (as attached) for voltage across capacitor wrt time. P=V^2/R The Attempt at a Solution I just wanted to know whether I've gone about this question in the right way. For the first part I simply rearranged the voltage...
  6. samjohnny

    Capacitor and Dielectric: Calculating Electric Fields and Stored Energy

    Homework Statement A parallel plate capacitor with plate area A = 100 cm^2 and plate separation of d = 5mm is connected to a 120 Volt power supply and allowed to fully charge. a) Calculate the capacitance, stored charge, electric field midway between the plates and potential energy stored...
  7. N

    Capacitance of an asymmetrical parallel plate capacitor

    I've been looking all over and to my great surprise have not be able to find an answer to this question. What is the capacitance between to parallel plates if one plate is larger than the other? For example, the capacitance between a 1" diameter plate and a 4" diameter plate. Thanks.
  8. T

    Does a Capacitor's Plate Resistance Work Like a Resistor's?

    Hello, Please I would like to know how the resistance of the plates of a capacitors work? Is it the same as a resistor? If yes, is there electric field like inside a resistor? Thank you
  9. K

    Inserting metal to parallel plate capacitor

    If there is a parallel plate capacitor with plate area, A, plate separation, d, and a slab of copper of thickness, b, is inserted exactly halfway between the plates. How to find it's new capacitance, C', and new potential difference, V' ? Answer: V' = E(d-b) and C' = εA / (d-b) I...
  10. X

    Can electrons "fly" between capacitor plates?

    How exactly do the electrons move from the capacitor to the rest of the circuit? Do they fly between the capacitors plates, or can they only travel where there is a wire connection? (I.e., if a small chunk of our circuit looks like this: A-------| |-------B can an electron start from A, go to...
  11. X

    Why does the potential difference between two capacitors seek equilibrium?

    Suppose we have a circuit with two capacitors connected to each other, C1 and C2. C1 is charged and has a potential difference of 5 V (V1=5V), but C2 is not charged (V2=0) Apparently it is known that the potential difference of these two capacitors will want to reach equilibrium. So V1=V2...
  12. burnst14

    Capacitor and Switch Potential Difference Calculations

    Homework Statement The switch is initially open and the capacitors are uncharged. The applied potential difference Vab = +210V. a.) What is the potential difference Vcd? b.) What is the potential difference across each capacitor when the switch is closed? c.) How much charge flowed through the...
  13. throneoo

    Energy in a shrinking spherical capacitor

    Homework Statement a conducting spherical shell has radius R and potential V. If you want, you can consider it to be part of a capacitor with the other shell at infinity. you compress the shell down to zero size while always keeping it spherical,while a battery holds the potential constant at...
  14. T

    Lost energy when capacitor discharges

    Homework Statement [/B] I have two capacitors: 1-Farad capacitor A, and 9-Farad capacitor B. In state (a), I charged A with 1 Coulomb of charges, as depicted in figure (a). In state (b), I paralleled A with B, by doing this I discharged A, as depicted in figure (b). I try to find the total...
  15. R

    Inserting Dielectric into a capacitor in parallel

    Homework Statement Two identical capacitors Ca and Cb each of capacitance 6.60 http://lon-capa.mines.edu/adm/jsMath/fonts/cmmi10/alpha/100/char16.png F are connected in parallel across a CONSTANT total electric potential difference of 480 V. A dielectric slab of dielectric constant 4.65 can...
  16. V

    Where Did I Go Wrong in Calculating the Electric Field Between Capacitor Plates?

    Homework Statement I have browsed similar threads and have only found more confusion. My question is if I have two parallel plates with an area A = 1m^2 and they are separated by a distance d = .03m. Each has a charge of Q and -Q respectively where Q = 1nC. I want to find the electric field...
  17. acdurbin953

    Charge on a capacitor in a series

    Homework Statement [/B] A circuit is constructed with five capacitors and a battery as shown. The values for the capacitors are: C1 = C5 = 3.9 μF, C2 = 3.9 μF, C3 = 5.7 μF, and C4 = 4.2 μF. The battery voltage is V = 12 V. What is Q5, the charge on capacitor C5? Homework Equations C=Q/V...
  18. D

    Capacitor needed for phase angle change (RLC network)

    Homework Statement An inductive load is connected to a 120V (rms), 60Hz AC source. The load draws 5.0 kW at a power factor of 0.81 (lagging). You need to improve your power factor to 0.96 (lagging) by adding a capacitor. What is the Capacitance needed (in uF)? Homework Equations P/|S| =...
  19. A

    Three plate capacitor and charge distribution

    In the figure given the capacitance for the two pair would be same. Can anybody please explain me how the charge would be distributed across each plate? I think that the middle plate being isolated should have +Q on one side and -Q on other, but how would be the charge distribution about the...
  20. Arjang Sh

    Can I Control Electrostatic Levitation with a Power Supply?

    Hello I need some advice about electrostatic levitation concept and am trying to make an experimental setup for that. Consider two parallel plates with the same sign charge and the bottom plate is fixed in place. Therefore there will be a repulsive force which pushes the upper plate...
  21. F

    Is the universe a huge capacitor?

    [Since "the universe is a capacitor" got zero hits on Google, I'm reasonably sure this is wrong, but I'm just not sure why it's wrong. Thanks in advance for your response.] ----------------------------------------------------------------------------------------------------- Batteries and...
  22. I

    Engineering Calculating net change of capacitor charge in a circuit

    Homework Statement This problem apparently has a simple solution if you are good with circuit theorems but no matter what i try or how i combine them, it's just impossible. Given a circuit on the picture, and circuit parameters E3=12V,R1=1kΩ,R2=30Ω,R3=150Ω,R6=200Ω, if it is known that current...
  23. B

    Series Combo Of Capacitors, Smaller Than Single Capacitor

    Homework Statement "A series combination of capacitors must always be smaller than the smallest individual capacitor." This is the statement that I am trying to validate, but I am stuck. Homework EquationsThe Attempt at a Solution [/B] I know that if you have a circuit that consists of a...
  24. M

    Discharging one side of a capacitor only

    Hey PF, I have a thought experiment that's been driving me nuts, here it is: I take a parallel plate capacitor charge it up to a steady state and then isolate / disconnect it from the electrical system leaving me with two charged parallel plates. I then hook up a power supply to two corners of...
  25. E

    Why Is There a Huge Discrepancy in My Capacitor's Measured Capacitance?

    Hello, I have made a capacitor with two aluminium foils separated with paper dielectric with, dielectric constant (K) = 3.8 for paper material paper thickness, D = 0.1mm = 1e-4 m plate or foil area, A = (12.1 x 8.3)cm = 0.010043 m air permitivity, Eo = 8.85e-12 F/m Calculated capacitance = (K...
  26. 2

    Transforming DC to AC: The Role of Inductors and Capacitors in RLC Circuits

    I have only just found out about inductors, and am trying to figure out how a circuit with an inductor and a capacitor could change dc current to ac current. With the set up of the circuit, would it suffice just to have the dc supply with a 'gate' that stops/allows through the dc current with a...
  27. J

    Working of capacitor in shock pen

    Can anyone explain the use of capacitor in a shock pen
  28. J

    How Does a Capacitor Increase Voltage in a Circuit?

    I have heard that a capacitor increases the voltage of output in a circuit can anyone explain it
  29. C

    Discharge of a Capacitor in a Magnetic Field: What Happens to the Momentum?

    Homework Statement A charged parallel plate capacitor with plates in the x-y plane and uniform electric field ##\mathbf E = E\hat z## is placed in a uniform magnetic field ##\mathbf B = B \hat x## i) A resistive wire is connected between the plates in the ##\hat z## direction, so that the...
  30. Rampart

    Bridge rectifier with capacitor

    Homework Statement For the following bridge rectifier you are asked to find the dc output voltage for the following errors: a)the capacitor is an open circuit b)one of the diodes is open c)the electrolytic capacitor is connected with reverse polarity The Attempt at a Solution My attempt is...
  31. C

    Electric Current in a Capacitor: What is it Called?

    How is the current that pushes electricity through the space between the two plates of the capacitor called?
  32. J

    How can I identify and fix a capacitor issue on my Kenwood A/V receiver?

    Hello everyone! I need help identifying a capacitor. It reads 12.C29 Its very small, maybe .25" long. It's on an audio input board from my Kenwood A/V receiver. Thanks for the help! Josh
  33. F

    Drawing a Circuit from Voltage-Time Graph

    Homework Statement The attached graph shows the relationship between time and voltage for three resistors. A capacitor is discharging current through three "separate" resistors. How resistors might be positioned in a circuit to give rise to the graphs.Homework Equations V = IR CR = $$\uptau$$...
  34. N

    Separation of subatomic particles within a capacitor

    I've recently taken to understanding capacitors and capacitance. If I understand them correctly they are what store electrical charge or electrical energy. I don't quite understand their purpose though, do they keep the breadboards from overloading with power but keeping little pockets of...
  35. A

    Full wave rectifier with capacitor filter

    i am having trouble finding out all the names given to the components in this circuit. Also i am struggling to find the names to the two different parts of the circuit. can anyone help me please?
  36. W

    Design of Power Factor Correction Capacitor?

    Hello... kindly help me out in designing of power capacitor to improve the power factor as the given load is 950 KWatt and power factor is 0.7, as i want to improve the power factor to 0.92 then what formula i should use to design the capacitor as the Voltage line to line are 400Volts
  37. B

    How Does Discharging a Capacitor Affect Its Internal Magnetic Field?

    Homework Statement A cylindrical parallel plate capacitor of radius R is discharged by an external current I. The total electric field flux inside the capacitor changes at a rate dΦe/dt = I/ ε0. What is the strength of the resulting magnetic field B(r, I) inside the capacitor at a radial...
  38. P

    What Happens to a Partially Inserted Dielectric in a Capacitor?

    1. The problem statement, Dielectric plate is placed in capacitor to the half(picture) and it can freely move. Capacitor consists of two parallel plates and is isolated. Consider two cases: a)charges on plates are constant, b)voltage is constant. What happens in each case? 2. Homework...
  39. arpon

    Both plates of capacitor connected to positve voltage

    If both the plates of a capacitor are connected to positve voltage, (but has a potential differnce between them) will the capacitor be charged? And how?
  40. S

    Is capacitor capacity linear with voltage?

    They are rated at 1V. Suppose they are in a 40V circuit, and rated to handle 40V. Would they then hold 40x the charge? I tried to calculate it base on electron repulsion, but I remember reading that electrons are not like gasses: they all go to the surface of the material in counter intuitive...
  41. S

    Does a capacitor have to have a dielectric?

    Suppose AC current is shooting into a wire, and the wire is attached to a bulk piece of metal off to the side of it, kind of like a ground, but not as deep as a ground. Wouldn't the bulk piece of metal work kind of like a capacitor and smooth out the voltage a bit? Everywhere I Google, I see the...
  42. Captain1024

    Obtain Expression For Voltage Across Capacitor

    Homework Statement A voltage source given by ##v_s(t)=25cos(2\pi\times10^3t-30^\circ)## is connected to a series RC load. If R = 1MOhm and C = 200pF, obtain an expression for ##v_c(t)##, the voltage across the capacitor. Answer known to be: ##v_c(t)=15.57cos(2\pi\times10^3t-81.5^\circ)##...
  43. Hijaz Aslam

    Charge induced on capacitor plates

    Homework Statement Three conducting capacitor plates are kept horizontally, above each other with a gap 'd'. If a charge ##+1\mu C## is kept on the middle plate what is the charge on the plates? Homework Equations (This question is theoretical) The Attempt at a Solution My textbook gave the...
  44. P

    Coilgun with car audio capacitors

    Hi guys, I'm new to this forum and I just started working on my first coilgun. I've watched several tutorials on how to build a coilgun but all the capacitors they use in the coilguns are electrolytic capacitors. The capacitors don't deliver as much energy as the car audio capacitors. I'm...
  45. Hijaz Aslam

    Discharging a charged capacitor to another neutral capacitor

    Homework Statement After a capacitor of capacitance ##C_1## is charged up to a voltage ##V_o##, the Battery is removed from the circuit. Another capacitor of capacitance ##C_2## is connected in series with the capaciotr ##C_1##. Find the charge on each capacitor after equilibrium is attained...
  46. A

    How to Read Capacitance on Ceramic Capacitors | 50 Diff. Capacitors

    I cannot find info on how to read capacitance on all these ceramic capacitors in my lab. I probably have 50 different capacitors but cannot find instructions on how to read most of them, any instructions I find on how to give the multiplier or whatever seems to apply to only a handful. and its'...
  47. T

    Can Three Inductors in a Circuit Act Like a Capacitor?

    Hyperthetically, say you had three inductors that each were ideal (90 deg lagging each) pf of zero. So there is a circuit with some current limited supply and you series these inductors up and excite the circuit. Is it going to look like a capacitor because the total angle is 270o like a...
  48. K

    Force on a Parallel Plates Capacitor

    Homework Statement A parallel plates capacitor has charge Q and the plates are at distance x. they are separated incremental distance dx. what is the force F to separate them. Homework Equations The capacity: ##C=\varepsilon\frac{A}{x}## The work done to charge a capacitor...
  49. Salvador

    Transfer of AC through rotating capacitor

    Hi, I need to transfer electricity to components that are rotating on a shaft but the power source is stationary with respect to the rotating shaft. the electricity is AC. So I had an idea of a rotating capacitor , two round plates , one stationary then a stationary dielectric attached to the...
  50. F

    Effect of capacitor plates at different angle

    Hi, I am interested to simulate the capacitor with plates having an angle of 195 degrees between them. https://dl.dropboxusercontent.com/u/32847378/cp1.jpg I know that if the angle between of plates is 180 deg, then electric lines of forces will follow a elliptical path and equipotential...
Back
Top