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MMC practical apps.



Ive been reading on the recent MMC trend and it seems to me that its a
great compact alternative. The only problem I see for the MMC is its
cost to coilers with small budgets like myself. I was reading Terry's
note on the falling capacitance and dielectric air pockets. Since most
coils incorporate the rolled poly or poly plate caps I was curious if
this dielectric bubbling could cause a similar problem for them as well?
I noticed a C reduction in my rolled cap before it died on my 4" coil
that I posted specs on a little bit ago. The reduction was quite small,
so small in fact that I never thought about it till now. I realize the
oil in the cap should fill these pockets of air as they form (if they
do) but could periodic re-vaccum pumping could help this? Since im sure
that not all air can be removed in the first pumping of the cap. My cap
only got hot and died spilling some smoke filled oil into the catch
bucket. My dissection of it revealed a spider effect on the poly surface
that looked like cracking of a car windshield when hit by a rock.
     Philip