The most important thing is that it be pulse rated. They are not really
very common. Polypropylene pulse caps can be had from Digikey and
others. Look for values you can make a decent size MMC from. There have
been a number of various values posted to the list, check the archives
at www.pupman-dot-com. There is some great data there. Most caps are rated
in DC volts. No big deal. Many are using DC=AC for the rating. The rule
of thumb in the past was to go with AC=2*DC. This is because AC puts
twice the stress on the caps as DC. You have to decide for yourself what
kind of rating you feel comfortable with. Commerical caps are
overdesigned, so you can push them a little harder if you want. 

For voltage, remember that the voltage of the individual caps will be
added up when you string them in series. If you have only 500V caps, you
will need a long string. The most common value on the list seems to be


Tesla List wrote:
> Original Poster: Ted Rosenberg <TRosen1-at-Tandy-dot-com>
> I like what I've read about using an MMC. I understand the theory and once
> the other modules are determined, I can use Wintesla or one of the other
> formulas to determine the capacitance and voltage I need.
> However, I have been looking through the Allied, Mouser, etc catalogs and I
> need to know two things...well, maybe three.
> 1. What generic type of cap do I look for (polypropylene? etc)
> 2. The working voltage spec...AC or DC, ie 1600 V in a Sprague Orange
> Drop...is 1000V OK? 2000V.
> 3. What spec in the caps description indicates that it is either good for an
> MMC or NOT good?
> Thanks and I continue to be overwhelmed by so much darned good information.
> Should start a scrapbook! <smile>
> Ted Rosenberg