What is Capacitors: Definition and 881 Discussions
A capacitor is a device that stores electrical energy in an electric field. It is a passive electronic component with two terminals.
The effect of a capacitor is known as capacitance. While some capacitance exists between any two electrical conductors in proximity in a circuit, a capacitor is a component designed to add capacitance to a circuit. The capacitor was originally known as a condenser or condensator. This name and its cognates are still widely used in many languages, but rarely in English, one notable exception being condenser microphones, also called capacitor microphones.
The physical form and construction of practical capacitors vary widely and many types of capacitor are in common use. Most capacitors contain at least two electrical conductors often in the form of metallic plates or surfaces separated by a dielectric medium. A conductor may be a foil, thin film, sintered bead of metal, or an electrolyte. The nonconducting dielectric acts to increase the capacitor's charge capacity. Materials commonly used as dielectrics include glass, ceramic, plastic film, paper, mica, air, and oxide layers. Capacitors are widely used as parts of electrical circuits in many common electrical devices. Unlike a resistor, an ideal capacitor does not dissipate energy, although real-life capacitors do dissipate a small amount (see Non-ideal behavior). When an electric potential (a voltage) is applied across the terminals of a capacitor, for example when a capacitor is connected across a battery, an electric field develops across the dielectric, causing a net positive charge to collect on one plate and net negative charge to collect on the other plate. No current actually flows through the dielectric. However, there is a flow of charge through the source circuit. If the condition is maintained sufficiently long, the current through the source circuit ceases. If a time-varying voltage is applied across the leads of the capacitor, the source experiences an ongoing current due to the charging and discharging cycles of the capacitor.
The earliest forms of capacitors were created in the 1740s, when European experimenters discovered that electric charge could be stored in water-filled glass jars that came to be known as Leyden jars. Today, capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass. In analog filter networks, they smooth the output of power supplies. In resonant circuits they tune radios to particular frequencies. In electric power transmission systems, they stabilize voltage and power flow. The property of energy storage in capacitors was exploited as dynamic memory in early digital computers, and still is in modern DRAM.
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...
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...
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
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...
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...
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...
[/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...
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?
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...
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...
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!
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...
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!
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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'...
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?
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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
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...
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...
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
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...
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...
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...
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...
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...
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...
For my electronics work I have a question to answer:
"A 1000V source is used to fully charge a 1μF capacitor. The capacitor is then disconnected from the source and connected to two additional capacitors (2μF and 8μF) as shown in the circuit schematic below.
a) Calculate the final voltage...
I was thinking of this following example:
Consider you charge a capacitor to its max with a battery, now replace the battery with a light bulb for example. The capacitor is starting to lose all the energy it had stored, is this a result due to entropy?
I mean I've learned that an increase...
Homework Statement
http://img99.imageshack.us/img99/763/prob45.gif
Fig. 1 and 2 show a dielectric slab being inserted between the plates of one of two identical capacitors, capacitor 2. Select the correct answer to each of the statements below (enter I for `increases', D for `decreases', or...