how do capacitors work?

Question

pls give scientific answers

Answer 1

A capacitor consists of two conducting plates placed close together. (Sometimes there are variations on this, such as a collection of interleaved plates; or "rolling up" the plates like a cinnamon roll.) But the point is, the two plates never touch each other.

If you connect the plates to a couple of wires, and then apply a voltage across the two wires (for example by connecting them to a battery), electrons will flow from the negative battery terminal and will charge one plate negatively. This creates an electric field that repels electrons away from the other plate, pushing those electrons into the battery's positive terminal.

This flow of electrons can't continue indefinitely. After a certain charge has built up on the plates, the battery is unable to push any more electrons onto the plate. By doubling the voltage on the battery, you can push twice as much charge onto the plates. In fact, the "capacitance" of a given capacitor is expressed in terms of how much charge per volt the capacitor can carry.

It typically takes only a fraction of a second for a capacitor to become fully charged (but this depends on the capacitor). Once it's charged, you can disconnect the battery, and the charge will remain on the plates (that is, one plate will remain positively charged while the other is negatively charged). This means there is energy stored in the capacitor, which makes it sort of like a (very weak) battery. If you have a charged capacitor, you can touch the two wires together, and it will "discharge," meaning that some electrons from the negative plate will run through the wire and over to the positive plate, until the two plates are "neutralized" and no longer charged. If you connect a charged capacitor to a light bulb, the flowing electrons will illuminate the bulb (for a very short time, until the capacitor is discharged). This is the way many flashbulbs in cameras work.

Another main use of capacitors is in AC (Alternating Current) circuits. If you just connect a battery to a capacitor as described above, the current stops flowing as soon as the capacitor is "full." But if you connect the capacitor to an Alternating Current source, it's like continuously switching the positive and negative poles of the battery. In this case, the capacitor just charges first one plate negatively, then the other plate negatively, over and over, so the current does not stop flowing. You can use capacitors along with other elements in an AC circuit to control and coordinate the circuit's voltage and current.

Answer 2

capacitors are electronic devices capable of storing electric charge.it stores it when current is passed into it
using the capacitor formula the energy stored in a capacitor can be known .the formula is
E=1/2CV^2
where c=capacitance of the capacitor
v=voltage across the capacitor

Answer 3

There are multiple ways to look at it. From an energy perspective they store energy in the electric field between their plates when the plates have opposite charges on them.

They can also be thought of as sort of a 'tank' for storing electric charge. Large 'filter' capacitors act like this in power supplies and backup power systems. Relaxation oscillator circuits use a capacitor by gradually "filling" and "emptying" it to create a time delay.

They also behave somewhat like a frequency dependent resistance in circuits like high and lowpass filters. They get used in power supply "bypassing" to short out high frequency noise and glitches.

A very versatile device!

Answer 4

This Site Might Help You.

RE:
how do capacitors work?
pls give scientific answers

Answer 5

Capacitors store energy and then release at a predetermined amount. Build up over time... Release... Build up... RElease...

Answer 6

http://en.wikipedia.org/wiki/Capacitors