[sdiy] .01uf Silver Mica

[harrybissell]

OK I could see that difference.

I'm equally confused.  Certainly what I'm talking about is
'soakage'

I think that Bob Pease wrote about it in one of his columns.
It would be like having a 100 uf cap... with a 1M resistor to
a 10uF...etc... 

Short out the 100uF and the voltage goes to zero... but unless
you wait a very long time... the 10uF will not discharge. If you remove
the
short... the 10uF cap will bleed back into the 100uF and recharge it.

I think maybe dielectric absorption as your describing is more like
dielectric losses.  The energy is lost as heat, and does not ever
come back.

Its pretty complex. The memory (soakage) can cause massive errors in
S/H circuits.  The losses are more an issue at high frequencies
(as you say)... and I'd think higher frequencies than we usually play
at

H^) harry

Ian Fritz wrote:
> 
> As I understand it, silver mica has a large dielectric memory (soakage)
> effect.  [See Horowitz and Hill, but note that they seem somewhat confused
> about dielectric absorption and dielectric memory, which they consider the
> same thing.  Dielectric absorption comes from the imaginary part of the
> dielectric constant and increases with frequency.  Dielectric memory is a
> permanent (DC) change in zero-field polarization.]
> 
> At 08:07 PM 1/24/06, harrybissell wrote:
> >Tempco is about the same, dielectric absorption of silver
> >mica is a little worse (not much)... temperature range of
> >silver mica is WAY better... but unless you gig the Mojave
> >Desert at noon, in July... under the hood of your car... :^P
> >
> >H^) harry
> >
> >James Patchell wrote:
> > >
> > > I am not sure what the tempco of the Micas are, but Polystyrene has a
> > > tempco of about -100ppM.
> > >