A
alejo2083
Guest
Hi everybody,
I am looking for information about how capacitors inside mobile phones
are made.
Obviously the main aim is to have the maximum value of capacitance with
a minimal use of space.
I've searched on Internet and I have found many
interesting things, but not exactly what I want to know.
As known, in an
capacitor made of two simple plates, the value of the capacitance is
directly proporzional to the area of the plates and the relative
permittivity,
and inversely proporzional to the distance between the plates.
I have tried to understand how much is the distance from the plates
used
nowadays, but I've not found anything. Obviously it has to be as small
as possible,
but if it is too small the tension of break down lowers, and there's
the problem of
the physical stability.
Moreover, in order to increase the capacitance, a dielectric between
two planes is interposed. Possibilities are ceramic (epsilon_r = 30)
distilled water
(epsilon_r = 80), but I read that there are materials called "titanate"
that they can have
epsilon_r = 10000!!
These last ones have the problem of a piezoelectric effect, but I
didn't understand
which it is the side negative in that...
I have read that nowadays in the mobiles the "tantalum" is used like
dielectric;
but I didn't find the value of epsilon_r
I read that sometimes many layers of different dielectrics are used:
but wouldn't
it be better just to use a single type, the one with greater the
dielectric permittivity?
Answering to these perplexities or indicating any documentation
would be VERY useful from me
Thanks to all
I am looking for information about how capacitors inside mobile phones
are made.
Obviously the main aim is to have the maximum value of capacitance with
a minimal use of space.
I've searched on Internet and I have found many
interesting things, but not exactly what I want to know.
As known, in an
capacitor made of two simple plates, the value of the capacitance is
directly proporzional to the area of the plates and the relative
permittivity,
and inversely proporzional to the distance between the plates.
I have tried to understand how much is the distance from the plates
used
nowadays, but I've not found anything. Obviously it has to be as small
as possible,
but if it is too small the tension of break down lowers, and there's
the problem of
the physical stability.
Moreover, in order to increase the capacitance, a dielectric between
two planes is interposed. Possibilities are ceramic (epsilon_r = 30)
distilled water
(epsilon_r = 80), but I read that there are materials called "titanate"
that they can have
epsilon_r = 10000!!
These last ones have the problem of a piezoelectric effect, but I
didn't understand
which it is the side negative in that...
I have read that nowadays in the mobiles the "tantalum" is used like
dielectric;
but I didn't find the value of epsilon_r
I read that sometimes many layers of different dielectrics are used:
but wouldn't
it be better just to use a single type, the one with greater the
dielectric permittivity?
Answering to these perplexities or indicating any documentation
would be VERY useful from me
Thanks to all