ameet,
I understand your question but from a purely technical point
your accretion that ("capacitors "allow" ac signals but "block"
dc signals" is incorrect). Capacitors appear to act in this manor but at an
engineering level however only a very tiny "leakage currant" actually passes
through the dielectric of a capacitor. If anything more were to pass
through it the dialectic insulator would be destroyed & the capacitor would
electrically short & them possibly become open or even explode depending on
how much energy was in the circuit.

Yes this is more technical than your question but I have always been 1
who questioned everything & I challenged my electronics teacher about this
since it did not fit my fundamental understanding of capacitor construction.
(Yes I asked him this after class) & he explained that my understanding was
in fact correct but that of practical reasons, in order to understand &
calculate how a capacitor works in a circuit this basic "capacitors "allow"
ac signals but "block"
dc signals" concept would need to be accepted as true.

It's always be interesting to me to learn why & where the "exceptions to
the rules" come from, some are required in order to simplify our basic
understandings of things. Electronics is much like pealing back layers of
an onion but yet you never seem to reach the center, at least that's how it
seems to me. I'm just a retired ET so my knowledge is limited but I try to
learn something new in this field everyday.

Respectfully, DHB

"ameet" wrote in message
om...
Now that I have heard that capacitors "allow" ac signals but "block"
dc signals as below.

Xc=1/[2(pi)(Fc)],

Fc=frequency of signal.

Now for dc signals Fc=0 Hz sothat Xc~infinity which implies that it is
open circuited,so we conclude that capacitor blocks dc signals and
allows ac signals(as they have a definite value of Fc).


But the problem is he Why do we use capacitors in radio circuits to
"block" noise signals which are nothing but ac signals?????

Can any one please explain where I am going wrong?????