Capacitors Definition and 884 Threads

  1. F

    Parallel Plates Capacitors, two capacitors.

    1. I mostly just need help understanding 3 and 4. And also understanding how to tell if things drawn on a circuit diagram/sketch are parallel or in series. I have the correct answer already, but it was mostly just guessing for 3 and 4. The sketch is a side view of two capacitors consisting...
  2. K

    Sum of capacitors connected in Series and in Parallel

    Homework Statement Find the sum value of capacitors. Homework Equations The Attempt at a Solution I tried to redraw the scheme like in the picture below, but my teacher told me it's not correctly redrawn. I hope You'll prove to me that my redrawn scheme is correct... If not I'm more than...
  3. P

    Waveclipper with capacitors as Voltage sources.

    Homework Statement A triangular wave generator produces a waveform oscillating at 1kHz. Draw a circuit that will clip the waveform, with peak values now at 5V. You may use a DC power supply witou outputs of +10 V & -10V as well as resistors, capacitors and standard signal diodes. Indicate...
  4. P

    Capacitors, Capacitance and Dielectrics

    Hi, So I am learning about parallel-plate capacitors. The way my book puts it is that it is basically two parallel plates of opposite polarities, separated by a distance d. In order to establish that distance, work must be done and the energy is stored as electric potential energy. From...
  5. M

    Making a Homemade Parallel Plate Capacitor

    I want to make a parallel plate capacitor without dielectric between it, that is, a capacitor with free space. Can I do a working capacitor with just a two parallel cardboard coated in aluminum? I figured it should look like this: Also, if there's anyone who's got a better idea on how I...
  6. A

    Do Plate Materials Affect Capacitor Performance?

    Hi I was wondering about an issue i thought about while attending a masters thesis dissertation earlier does the material of the plate (not the filling dielectric) affect capacitance (even if in the fringing level) ? Check the attached picture , for a better explanation
  7. C

    Capacitor charged and disconnected then connected to capacitors

    Initially, a 15uF capacitor is charged by a 100V battery. Once charged, it is disconnected from the battery and connected to two uncharged capacitors(C_2 = 20uF, C_3 = 30uF) in parallel. What is the charge and potential difference on each capacitor. (The two capacitors mentioned above are in...
  8. C

    Capacitors with different dielectric constants

    Two capacitors have the same plate separation, but one has square plates and the other has circular plates. The square plates are a length L on each side, and the diameter of the circular plate is L. The capacitors have the same capacitance because they contain different dielectric materials...
  9. W

    Conceptual Question on Parallel Plate Capacitors

    Homework Statement Two capacitors, C1 and C2, are separately charged to 166 C and 348 C, respectively. They are then attached in parallel so that the + plate of one goes to the - plate of the other, and vice versa, as shown on the diagram below (notice how C2 was rotated 180 degrees before...
  10. M

    Why Bypass Capacitors Need Grounding

    Why do we branch off and go to ground on bypass capacitors instead of just putting a capacitor inline? Surely the effect would be the same?
  11. D

    A doubt about inductors and capacitors

    [/itex]Hi I am new here :smile: I know (correct me if wrong please :smile:) that inductors store current in its magnetic field, and capacitors store voltage in its electric field But, why when disconnecting a inductor charged from a DC circuit, a spark is produced at the disconnected...
  12. Femme_physics

    Do the capacitors always charge exponentially?

    The way I see it, the more the plates charge, the harder it is to charge them. Therefor capacitors always charge exponentially and linearly. Is that right?
  13. W

    Tantalum vs Ceramic Capacitors

    Hi Guys, I'm doing a research on capacitors and wondering if someone would be so kind to give me some help. I understand that both tantalum and ceramic capacitors can be used in smartphone/tablets. I'm wondering: 1) What's the advantage of one versus the other? 2) What is the...
  14. H

    Derating PFC Capacitors for 50Hz Wind Turbine Conversion | Expert Tips

    I'm converting a first generation, fixed speed wind turbine from 60Hz operation to 50Hz operation. There are passive PFC capacitor banks in the downtower box on the turbine. How are the capacitor banks derated for 50 Hz operation? Is it as simple as, for example, downsizing from 15 to 12.5...
  15. W

    Capacitors in Cars: What Parts & Types?

    Hi! Does anyone know which parts of an automobile would require the use of capacitors? Also, what kinds of capacitors are used in this case? (aluminum, tantalum, ceramic, ??) Many thanks!
  16. D

    The voltage of the 2uf capacitor will be the sum of the two source voltages.

    the topic "capacitors" Hi everyone! while i was working out questions on the topic "capacitors", got stuck somewhere... and my problem is Suppose the arrangement is like ... So two questions are points of my confusion... (1) what will be the direction of flow of current? (2) and...
  17. W

    Capacitors for power utilities and electric apparatus

    Hi! I am doing a research on a specific company and they made 'Capacitors for power utilities and electric apparatus'. Would someone be so nice to tell what kinds of capacitors they are? (Aluminum, tantalum, etc?) Thanks!
  18. W

    What are the main applications of aluminum capacitors?

    Hi guys, I am doing a research on the capacitor industry and would like to ask some question. I did some basic research online that find out that aluminum capacitors are mainly used in the following areas. Power supply output filter Blocking and dc-bypass circuits Motor start and...
  19. T

    Final charges on the capacitors

    Homework Statement The Problem is as follows :- https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/224892_2277870043526_218311126_n.jpg Three capacitors of 2 μF, 3μF, and 5μF are indulgently charged with batteries of emf’s 5V,20V and 10V respectively. After disconnected...
  20. M

    Practical Application of Capacitors

    I was thinking that a car battery is a 12v source that delivers between 300 and 900 cold cranking camps. That'd put the cranking wattage at between 3600 watts and 10,800, right? Here's a car battery 'helper': http://goo.gl/Roo2l This is hypothetical at this point but what I was wondering...
  21. T

    Distribution of charge in two charged capacitors joined in a circuit

    Hello! I'm having a bit of a struggle understanding the logic behind these two questions. A 2.2 uF capacitor is charged to a potential of 15V, and a 3.3uF capacitor is charged to a potential of 30V. The capacitors are then joined together as in the circuit diagram. When the switch s is...
  22. R

    Voltage across Capacitors in Parallel

    Homework Statement A 10μF capacitor is charged to 5V and then isolated. It is then connected across a second uncharged capacitor of capacitance 15μF. The potential difference, in V, across both capacitors is A) 0.2 B) 0.5 C) 2 D) 3 Homework Equations C= Q/V Ct=C1+C2 The...
  23. A

    Combination of Capacitors and Equivalent Capacitance

    Homework Statement Calculate the charge on C1 in Coulombs. Homework Equations umm q=CV The Attempt at a Solution http://answers.yahoo.com/question/index?qid=20120424171750AA1WxRv I have this same problem except my numbers are: C1= 6.00 μF, C2=3.10 μF, C3= 2.20 μF, C4= 1.30...
  24. K

    Find the equivalent impedance of an infinite series of resistors and capacitors

    Homework Statement Find the equivalent impedance of the infinite series of resistors and capacitors as shown below -R----R----R----R----...R----... ____C____C____C____B_______C -r----r----r----r----...r----... Homework Equations 2.1. Equivalent resistance of resistors in series : R = R1 + R2...
  25. K

    Question over Coupling capacitors and Op-Amps

    So this is the op amp I am looking at and I have a few questions, not entirely sure how to ask them, but I'll ask more as I find out more http://postimage.org/image/i228xrkj7/ http://postimage.org/image/i228xrkj7/ So the capacitor C1 and C3 are used to block DC, but when you add these do you...
  26. Saitama

    Individual Spherical Capacitors

    Homework Statement Two conducting spheres of radii R1 and R2 are kept widely separated from each other. What are their individual capacitance? If the spheres are connected by a metal wire, what will be the capacitance of the combination? Think in terms of series-parallel connections...
  27. D

    Help to replace blown capacitors on UPS

    Hi there, I have a UPS which seems to have blown up two capacitors inside. It is a cyberpower 2200VA UPS I was running the UPS from a generator when it must have surged or something ... there were two quite big puffs of smoke that came out of the fan exhaust of the UPS. And then the UPS was...
  28. Z

    Parallel Capacitors: Homework Solution for 9 μF Charge

    Homework Statement A capacitor of capacitance 9 μF is fully charged from a 200 V dc supply. The capacitor is now disconnected from the supply and connected in parallel with an uncharged 3 μF capacitor. Once the 3 μF capacitor is fully charged, it is removed and discharged. a) What charge...
  29. C

    Capacitors in a multiphase voltage multiplier?

    what should be the ratio between the capacitance of the capacitors in the three AC lines , and that of the capacitors in the DC line at the bottom? should all the capacitors be the same value ... even though there are AC lines, with an identical capacitor in each of them, the total 'linear'...
  30. T

    Charging two parallel capacitors one of them is %50 charged

    hi i need an equation which can describe the charging time of two parallel capacitors one of them is %50 charged and if i have a capacitor which is always charged from 50% to 100% and never fully discharged will it have a different impedance than the fully charged/discharged capacitor?
  31. P

    Derivation for E = V/d? (capacitors)

    One of the formulas I came across while doing problems with simple parallel plate capacitors was E = V/d, where E is the magnitude of the electric field between the plates, V is the potential difference between the plates, and d is the separation of the plates. I'm wondering where this formula...
  32. G

    Paralleling capacitors effect on total esr reduction.

    Hi and thanks for taking the time to read this post. I am trying to decide component values for 2 parallel capacitors, in an effort to reduce esr, which will be for use as power supply smoothing capacitors to be placed after the bridge rectifier. After examination i noticed that consumer...
  33. N

    Capacitors in common emitter audio amplifier

    Homework Statement Hello. When I looked at my lab manual, I saw the capacitor CB is connected in reversed direction. The AC source is connected to resistor RS, then connected to the negative polarity of CB. But I have no idea why it connects in reverse. Can please anyone tell me the reason...
  34. L

    Capacitors & Electric Fields and how they change relative to each other

    1. I have a capacitor that has been fully charged with a 10v source, then that source is removed. If I increase the distance between the plates, does the electric field stay the same, and the voltage increase, or does the voltage stay the same, and the field decrease? Or is it something that...
  35. J

    How Does a Capacitor Affect the Voltage Output of a Power Source?

    Homework Statement see attachment Homework Equations The Attempt at a Solution here are the MS points : Capacitor stores charge/charges up (1) (If voltage is constant) capacitor doesn’t discharge (1) I don't understand how the answer makes sense. The question asks how...
  36. T

    Capacitors in DC Circuits, and How it Affects Reactance & Current

    I read that capacitors that are part of DC circuits have a reactance that is essentially infinite. When I look at equations, this seems to make sense: If the reactance X=1/ωC, ω is zero in a dc circuit and so this means that X approaches a very large value. Thus, if you use V=IX, this means...
  37. L

    Bypass capacitors and bulk capacitors

    I'm trying to understand the role of bypass caps and bulk caps, applied specifically to FPGA and other digital ckts. Bypass caps provide a low impedance path to the noise on the supply lines and also supply switching currents for the logic devices. But what's the role of bulk caps? Henry ott's...
  38. S

    State space modeling of parallel capacitors

    Hi there, I have been thinking about how to actually describe a system input filter consisting of several caps and an inductance in the state-space representation. The topology follows: a DC source to inductor to two parallel caps that are referenced to the same potential as the voltage...
  39. D

    Placing electrolytic capacitors in an amplifier circuit.

    I am working various amplifiers in my labs. On nearly all of these amplifers (CC, CE, or CB), the input signal is capacative coupled. However, the cricuit schematic indicates the use of a polarized capacitor. The capacitors I am using are rated at a maximum voltage of 50V. Most of the voltage...
  40. R

    Capacitors in a circuit / Calculate total capacitance

    Homework Statement Capacitors are connected as shown in this diagram: http://o3xn.files.wordpress.com/2012/04/c4.png C1 = 2 μF, C2 = 1 μF. What is the total capacitance of the system in between the terminals A and B? Homework Equations For capacitors C1 and C2 connected in...
  41. D

    What is the equation switched capacitors

    HELLO what is the equation that describes the relation between the charging current i(vdd) and that switched capacitors ( c1,c2,c3,c4,c5) if we put into consideration that switches are closing in sequence switch 1,switch 2, . . .switch 5 with a delay time of td thanks
  42. J

    Charging and discharging capacitors - current time graph

    Homework Statement why is the current-time graph for a charging AND discharging capacitor the same? Homework Equations The Attempt at a Solution Q=It so for a discharging capacitor as time goes on the charge stored decreases so current decreases BUT for a charging capacitor...
  43. J

    AC Theory question with capacitors

    Three uncharged capacitors each of 1uF are connected in parallel and the combination connected to a 100V power supply via a 1MΩ resistor. After 2s the capacitors are removed, connected in series and the new combination allowed to discharge through a 10kΩ resistor. Find the discharge current...
  44. W

    Charging and Discharging capacitors

    A 38 μF capacitor is charged to an unknown potential V0 and then connected across an initially uncharged 13 μF capacitor. If the final potential difference across the 38 μF capacitor is 37 V, determine V0. Answer in units of VQ=C∆V
  45. N

    Conceptual question regarding inductors and capacitors

    Homework Statement http://img207.imageshack.us/img207/3756/24134024.jpg N.B: (0+) means just after switch is open, and (0-) means just before switch is open. I have the solutions for this, but there are some problems I have with understanding how inductors and capacitors work in...
  46. E

    Circuit with capacitors and inductors

    The question states that the circuit has been connected for a very long time. I'm assuming that then, the current will remain constant and thus the voltage for the inductor is vL = Ldi/dt = 0. Thus, using nodal analysis, I was able to solve (a) by eliminating all of the inductors from the...
  47. L

    Variance between two parallel plate capacitors

    I have performed the Millikan oil drop experiment, but after a acquiring data for 14 drops it was impossible to collect anymore data because the drops would keep moving out of view under the influence of an electric field. The thing is I made sure that everything was as level as possible and I...
  48. J

    Questions about capacitors, and arduino

    hey all, I've been playing around with capacitors and have a few questions Is it possible to get 5 volts over a capacitor using a AA batery? Or am I limited to 1.5 volts? If I have more than 5 volts going into an arduino pin, that will cause damage. But I can use a voltage divider to drop...
  49. M

    Understanding the Effects of Dielectrics on Capacitors

    Homework Statement When a dielectric is inserted in a capacitor, why does the charge remain unchanged while the potential decreases and capacitance increase? Homework Equations The Attempt at a Solution i'm not really about this one, but is it because the charges accumulate on the surface area...
  50. A

    How does charge accumulate on the plates in a capacitor?

    I'm taking my first Physics course dealing with electricity and magnetism, and I am finding it incredibly difficult. I have a number of questions that are driving me insane, and I hope that some of you will be able to clear things up for me--I would greatly appreciate it. We are covering...
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