Capacitor Definition and 1000 Threads

  1. F

    Relay and Capacitor circuit - blinking LED

    Hello Forum, I am having issue understanding what is going on with the circuit below which is supposed to blink an LED by alternatively pulling the switch up and down which results in opening and closing the circuit the LED is part of (lower circuit portion). This is what I am confused about...
  2. E

    Is My Super Capacitor Power Bank Circuit Safe?

    I'll make a power bank with capacitors and I made circuit of it. But I'm worrying about whether the circuit is safe, because it's dangerous to use capacitor. So, can you check the circuit i made?? My capacitor is 2.7V, 600F and the power bank circuit has "Charging current : 1A maximum, output...
  3. johnboyman

    Trying to calculate the peak current of a Capacitor bank

    Hello I am building a Tesla Coil. I built it well I attached an image of the circuit I used. I bought a 15,000 volt transformer rated at 30 ma. I think it is too small for my tesla coil because it keeps blowing a fuses and a red light turns on. Here are the specs. -Inductance (L): 17 uH...
  4. Charlie Cheap

    Using a capacitor for RFI protection

    It has been decades since I was in electronics school and I forgot a lot. I was told using copper plug wires could hurt modern electronic ignition parts, and I was wondering if an RFI capacitor (.5 mfd.) would help protect things. I have a 4-cylinder with points that have been changed to a...
  5. patrykh18

    Stress tensor for a parallel plate capacitor

    The question is partially taken from Griffith's book. I am confused about the physical meaning of momentum in fields. I have determined the solution and found that in part d the momentum crossing the x-y plane is some value in the positive z direction. I don't however understand the physical...
  6. M

    Engineering AC circuit: Find the current through the inductor & capacitor

    Hi! I wonder if it is correct. Can someone confirm (maybe with a software) ? I(L) = I2 I(C) = I2 - I3 -- Thanks.
  7. Peter Alexander

    Probability from the tolerance of a capacitor (Gaussian distribution)

    Given the upper data, if the nominal value for capacitance is 33nF and tolerance of 20%, then values can range between 26.4nF and 39.6nF. With the bottom margin being set at 30nF, this means that the interval takes approximately 72% of all values. Is this the correct procedure to solve this...
  8. wolram

    My amplifier -- why did this capacitor blow in my guitar amp?

    I have built several guitar amps, but the last one I built burned out a capacitor, can anyone think of a reson for this? it was an eloctolytic, all is working fine now I replaced it.
  9. Tryhard314

    Voltage drop across a capacitor and resistor in series

    In this circuit a battery,Capacitor,and a resistance are in series. For simplicity assume that there is a +4V in the positive terminal of the battery and -4V in the negative one and let A be the capacitor plate connected to the positive terminal and B the capacitor plate connected to the...
  10. L

    Determine the effective current value in the circuit with C and R

    Given: U = 220 V f = 50 Hz r = 20 Ohm C = 100 μF Find: I Solution: 1) Xc = 1/(ω*C) = 1/(2*π*f*C) = 1/(2*π*50*10^-4) = 31.83 Ohm 2) R_eq - equivalent resistance R_eq = (r*Xc)/(r+Xc) = (20*31.83)/(20+31.83) = 12.28 Ohm 3) I = U/R_eq = 220/12.28 = 17.9 A True answer given in the textbook is 13 A...
  11. engnrshyckh

    Power supplied by a Capacitor and Inductor

    Using above eq Xc=80.38Ohm and P=179VAR but textbook says that the ans is zero. Can anyone explain please
  12. brainbaby

    How does the tapped capacitor network increase the impedance?

    Please help me comprehend the text below... The discussion begins with the current flowing through the inductor for both the cases (case a and b) stays same.The input voltage is Vi. When two tapped cap is used with the current that is flowing in the inductor is divided among the two capacitor...
  13. George Young

    Question About Wiring a Capacitor

    EDIT: I looked this up and I don't think you can do what I originally thought of. Instead, you can use switches. Not that complicated. I'd delete the thread but they don't usually like to let you do that. I just asked because I don't know much about capacitors and I thought I might learn...
  14. Boltzman Oscillation

    Engineering How do I find the electric fields for this capacitor?

    the image is given here along with some numerical information: Now I know that the formula for the electric field in a capacitor is given as: $$E = \frac{V}{d}$$ which I can use to obtain the three following fomulas: $$E_1 = \frac{V_1}{d}$$ $$E_2 = \frac{V_2}{d}$$ $$E_3 = \frac{V_3}{d}$$ where...
  15. M

    Find the charge on the plates of a parallel-plate capacitor w/ dielectric

    This is an online HW question so maybe my digits are just off from rounding or something, but I don't know why I am not finding the correct answer. I got Q = 6.9e-8 as the magnitude of charge on each plate. I basically just needed to calculate the original capacitance of this capacitor using c...
  16. U

    Signal Generator, Oscilloscope and Capacitor

    I started by working out the time constant of the Capacitor = RC = 300 * 1.5*10^-9 = 0.45 *10^-6 and the time period (t) of the square wave signal produced by the signal generator : 1/(1*10^6 )= 10^-6 Then I drawed the graph as follows...
  17. L

    Dielectric interface plate capacitor at angle alpha

    Consider a plate capacitor with a dielectric interface (\epsilon = \epsilon_0*\epsilon_r, thickness=d) tilted at the angle \alpha . Outside the interface \epsilon = \epsilon_0. Without dielectric interface is the field \vec{E}=E_0*\vec{e_z}. Determine the E-field inside and outside the...
  18. akaliuseheal

    Calculating the capacitance of a capacitor

    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...
  19. D

    Parallel Plate Capacitor Design

    Hello, A question came up in my head that I couldn't think of a way to math out. Say I want to design a parallel plate capacitor. The equation for capacitance is quite simple: Everything in this equation makes sense, besides for the distance. This is saying that an infinitely small length...
  20. J

    Engineering Calculating the gap of a parallel plate capacitor

    I've been given this question for my TMA2, I've tried looking at the learning material but it gives no information on how to calculate the gap? Does anyone have a formula for this? Or can someone point me in the right direction? Thanks
  21. O

    Wiring a permanent split capacitor motor

    Greetings This query is regarding a 5 wire induction motor without a wiring diagram from a washing machine, one permanent capacitor, no centrifugal switch. here its 240v 50hz I would appreciate someone explaining how to actually figure out the connections after measuring the resistance of the...
  22. I

    Inserting a dielectric material between two plates of a capacitor

    1. new capacity: ##C = K\cdot C_{0}##. 2. initial potential energy: ##U_{i} = \frac 1 2 \cdot C_{0}V_{0}^2##. 3. final potential energy: ##U_{f} = \frac 1 2 \cdot KC_{0}V_{0}^2##. 4. total work done: ##W_{tot} =\Delta U = U_{f} - U_{i} = \frac 1 2 \cdot (K-1)C_{0}V_{0}^2 > 0##. 5. also total...
  23. J

    Question Regarding Parallel Plate Capacitor Network

    Hello, I have a question regarding the capacitor/resistor network as shown. My question is simple. I realize that the instant the switch is closed, then the top plate of the capacitor must be at a potential (VA) of 5v. However, I also realize that the instant the switch is closed, literally...
  24. Hawkingo

    What is the effect of the dielectric material on Gauss' law?

    [PAGE 1] [PAGE 2] [PAGE 3] so in the 2nd page,when the dielectric material is introduced the gauss's law becomes $$\oint _ { S } \vec { E } \cdot \vec { d S } = \frac { ( q - q _ { i } ) } { \epsilon _ { 0 } }$$.But my question is why the ##{ \epsilon _ { 0 } }## is in the equation.Shouldn't...
  25. rofldude188

    Capacitor Problem with distance-dependent dieletric

    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...
  26. Zahid Iftikhar

    Why does a capacitor charge to 63% of the applied voltage?

    Statement of problem is given in the summary. Mathematics proves time constant is calculated from the equation V= V0 exp t/RC I want to know if there is any physical explanation of this effect. Please guide me on this. Regards
  27. wirefree

    Engineering How Does a Capacitor Affect Ripple Voltage in a Diode Circuit?

    Summary: Seek help with the working of a Capacitor in the presence of a DC & AC voltage source. I greatly appreciate this opportunity to submit a question. It's a homework problem and I only seek to clear my concepts. Problem: Find amplitude of the ripple voltage across the resistor...
  28. shushi

    Novice question about Relays, Capacitors, and Diodes

    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...
  29. K

    What does "Fully Charged Capacitor" mean?

    Why when a capacitor is fully charged the circuit is acting like an open circuit? And what is the meaning of "fully charged", if the charge as a function of time equation is: $$ Q = CV_b [1 - e^{\frac{t}{RC}}] $$ so by this equation the charge on the capacitor will never reach exactly, Q = CV...
  30. baywa2

    Determine the capacitor value so that this circuit is in resonance

    L=100mh=0.1H ω=10^3 rad/s -> f = 159Hz XL= ωL= 2πfL= 2π*159*0.1= 99.90 Ω Z parallel = [(XL∠90º)*R2] / [(XL∠90º)-R2]= 37.13∠-21.8º XC= 1/ωC= 1/(2 π f C) I don't see how I am supposed to get to C
  31. E

    Can a capacitor discharge as a result of being struck?

    I am curious if a large dielectric capacitor on the verge of discharge could be put over the edge by physically hitting it.
  32. A

    A capacitor with two dielectrics in series

    Hi, I would like to know how to calculate the total capacitance for a capacitor that has a certain plate overlap area and two dielectrics in between, one being a solid state dielectric and the other one being air. This is not a school project, I just thought about it and tried to calculate...
  33. maxipoblete

    Capacitance of a circular capacitor with two parallel dielectrics

    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?
  34. brainbaby

    Role of the capacitor, coil and choke in this television receiver design

    Hi friends, I am studying this circuit which is the first all electronic television receiver created by Dr. Farnsworth back in 1927. Triode are being employed along with some caps and coils. The design is very simple and clear, basically this receiver is a detector circuit which detects the...
  35. H

    Timer based switch for a power capacitor

    To cover transformer loss at no load and maintain pf, we are needing 6kvar at day time and 9 kvar at evening. Is there any time based switch available, such that it can switch ON 3 kvar at evening, say 8:00pm and turn off automatically at 8:00AM morning
  36. Y

    Not understanding work stored in a capacitor

    I know V = q/c and W = Vq and dW = V dq. But why is Work in charging a capacitor W = integral of q/c dq? q seems to represent a charge on the capacitor plate and dq seems to represent a separate test charge. If I add a charge to the capacitor plate, I take take the resulting votage and multiply...
  37. C

    I RC charging - intuition behind equal dissipated energies?

    Assume that a resistor R charges a capacitor C, whose other terminal is connected to the ground. The charge at time t = 0 is assumed to be null and the supply voltage is equal to V. We have, as is well known, ##i = \frac{V}{R} e^{-\frac{t}{RC}}##. Integrating ##\frac{i^2}{R}## between t = 0 and...
  38. T

    Capacitance and induced charge of a spherical Capacitor + dielectric

    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...
  39. Tesladude

    What is the voltage across this capacitor, inductor and resistor?

    I can solve for the questions in completely series or parallel circuits however having the capacitor and inductor in parallel while the resistor stays in series is stumping me completely.
  40. M

    Charged Capacitor Connected to an Uncharged Capacitor in Series

    I have already solved up to after the switches are flipped, and all the charge is on C1. See the second attached image for a detailed diagram of the situation after the switches are flipped. However, the notes then say that all the charge is trapped between C1 and C2, which I don't understand...
  41. T

    Capacitor and electrostatic field

    Is there any electrostatic field around the leads of a charged capacitor? Let's take just the negative one. If I take a piece of tissue and put close to that terminal it will attract or repel the paper? And if not, why?
  42. K

    Spherical capacitor with dielectrics

    Homework Statement Consider the following system: which consists of a conducting sphere with free charge , a dielectric shell with permittivity ##\epsilon_1##, another dielectric shell with permittivity ##\epsilon_2## and finally a conducting spherical shell with no free charge. Homework...
  43. R

    How Do You Solve This Capacitor Problem with Aluminum Electrodes?

    Homework Statement Two 5.0-cm-diameter aluminum electrodes are spaced 0.50 mm apart. The electrodes are connected to a 200 V battery. Homework Equations C = εA/d The Attempt at a Solution So for my solution I took the area of the plate, ((.052π) * 8.85*10-12) / .5*10-3 and I got an answer of...
  44. Muhammad Usman

    How does a Capacitor protect against voltage spikes?

    Hi Everyone ! I have one confusion regarding the role of the capacitor in the circuit. How does the capacitor protects the circuit from the high voltage spikes. If the capacitor is connected from the circuit with battery. And sudden high spikes come then the capacitor is charged and the energy...
  45. G

    How to treat the "ideal" plate capacitor more rigorously?

    Hi. The derivation of the capacity of an ideal parallel-plate capacitor is inconsistent: On the one hand, the plates are assumed to be infinitely large to exploit symmetries to compute an expression for the electric field, on the other the area is finite to get a finite expression for the...
  46. Muhammad Usman

    Understanding Capacitor Behavior for Noise Filtering?

    --> Hi, I am reading about the capacitors. I have read that the capacitors block DC and behaves as open circuit in DC while short circuit in AC. The reason behind this is the charging and discharging of the capacitor. What is my perception about it, I will mention about it. " During the DC...
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