capacitor help

[derek13]

could anybodyplease explain in laymans terms wat exactly a capacitor does ?have a basic understanding but would like to know more if anybody could spare the time please?? :Y

cheers!!!!

 

[Andy™]

like a little battery - stores power and releases it

 

[ABC Technical]

A Capacitor has the ability of a system to store electric charge, equivalent to the ratio of the change in electric charge to the corresponding change in electric potential.

 

[Apache]

Think of it like stored static electricity to be discharged - used in disposable camera flash's!

(they bite : O)

see wiki http://en.wikipedia.org/wiki/Capacitor

 

[extension15]

could anybodyplease explain in laymans terms wat exactly a capacitor does ?have a basic understanding but would like to know more if anybody could spare the time please?? :Y cheers!!!!

A capacitor is generally used in circuits where alternating voltages (AC) exist.

Such as Radios (Radio Frequency), Power supplies (AC to DC) for smoothing out the ripple left after rectification.

For blocking D.C. (Direct current) in a AC couple circuit.

Filtering and Power Correction in a Florescent light fitting.

It is also used in DC circuits for stability and timing.

It is along with the resistor a passive component.

 

[oliver1234]

All good answers so far, a capacitor tends to conduct AC but tends to block conduct DC, kind of like the opposite of an inductor.

 

[MajorOak]

A pure resistance acts the same on AC circuits (RMS) and DC circuits

A capacitor is made up of two metal plates separated by insulation. A capacitor responds to the rate of change of voltage across the plates, which is the frequency of the AC circuit, this is called capacitive reactance and this is a form of resistance.

Capacitive Reactance = XC = 1/(2*pi*f*c)

where

pi = 3.147...

f = frequency

c = capacitance in farads

An inductor is a coil of wire. An inductor responds to the rate of change of current flowing through the coil, again the frequency of the ac circuit, this is what is called inductive reactance; this is also a form of resistance.

Inductive Reactance = XL = 2*pi*f*L

where

pi = 3.147...

f = frequency

L = inductance in henrys

Ignoring all the other symbols apart from f, which is frequency, you get

Capacitive Reactance is proportional to (∝) XC so ∝ 1/f

And

Inductive Reactance is proportional to (∝) XL so XL ∝ f

Capacitance

As f (frequency) drops to zero, which is DC, XC goes to infinity, so infinite resistance. So as people have said it blocks DC. It is basically an open circuit to steady state DC. If you increase f, XC starts to fall and so becomes a lower resistance the higher the frequency gets, passes AC.

Inductance

As f drops to zero, which is DC, XL drops to zero. So it has no resistance to steady state DC. If you increase f, then the resistance increases and so will start to block or reduce the current through the circuit, blocks AC.

If you combine the capacitive reactance, inductive reactance and resistance you will get impedance, which is an AC circuit

 

[johnston1991]

also used to control the phase angle and change power factors, such as in flourecent lights ect. with good old. C.I.V.I.L

by lowering the inductance of the circuit with capacitance it lowers the phase angle and brings it closer to being 0 which is a perfect pf but imposible so im told?

 

[Andy™]

Nice post. Welcome to the madhouse