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Dielectric absorption and dissipation factor

E

Eeyore

Jan 1, 1970
0
I'm curious about DA and DF in capacitors especially with regard to plastic film
types.

DA in plastic films caps would appear to be related to the electret effect.
Presumably it's therefore simply material dependent ?

DF I'm less clear about but it looks to me to be related to the resistance of
the metal involved so film/foil types have lower DF than metallised foil. Is it
just that simple ?

Is anyone aware of any non-linearirty in the dielectric constant of plastic
films with applied voltage btw ?

Graham
 
L

LVMarc

Jan 1, 1970
0
Eeyore said:
I'm curious about DA and DF in capacitors especially with regard to plastic film
types.

DA in plastic films caps would appear to be related to the electret effect.
Presumably it's therefore simply material dependent ?

DF I'm less clear about but it looks to me to be related to the resistance of
the metal involved so film/foil types have lower DF than metallised foil. Is it
just that simple ?

Is anyone aware of any non-linearirty in the dielectric constant of plastic
films with applied voltage btw ?

Graham
Graham,

The dielectric constant absolutley changes with frequency. The DF points
to an equivalent resitnace and as well as bing related to the losss also
is a factor in the crner frequrncy of the dielectric constant.

Dielectrci absortion is a who;e different animal

marc Popek
 
E

Eeyore

Jan 1, 1970
0
LVMarc said:
Graham,

The dielectric constant absolutley changes with frequency.

That's a completely new one on me. Can you point me in the direction of any data about
that ?

The DF points
to an equivalent resitnace and as well as bing related to the losss also
is a factor in the crner frequrncy of the dielectric constant.

Dielectrci absortion is a who;e different animal

Indeed.

Graham
 
P

Phil Allison

Jan 1, 1970
0
"Eeysore"
I've already been there Phil.


** Blatant, fucking lie.

I was hoping someone with specific experience might be around here.



** That is *** NOT *** what you question posted above says


- You DAMN LIAR .





........ Phil
 
P

PeteS

Jan 1, 1970
0
Eeyore said:
I'm curious about DA and DF in capacitors especially with regard to plastic film
types.

DA in plastic films caps would appear to be related to the electret effect.
Presumably it's therefore simply material dependent ?

DF I'm less clear about but it looks to me to be related to the resistance of
the metal involved so film/foil types have lower DF than metallised foil. Is it
just that simple ?

Is anyone aware of any non-linearirty in the dielectric constant of plastic
films with applied voltage btw ?

Graham

Hi Graham.

Dissipation factor is sometimes also known as the loss tangent and is
of particular interest on high speed PCBs. Certainly PCB material has
loss tangents specified at various frequencies - I'll see if I have
anything here, otherwise I'll dig out some datasheets once I get home
this evening.

Pretty good comparison here:

http://www.rfcafe.com/references/electrical/dielectric_constants_strengths.htm

Cheers

PeteS
 
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