# Re: Caps

```Original poster: "Jason Petrou by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jasonp-at-btinternet-dot-com>

Ben,

> Here is what I am working with: a 9/30 transformer
Fine, no probs with that

> I am trying to copy Sam Barros Coil(http://www.powerlabs-dot-org/coil2.htm)
with
> a few modifactions such as caps.
Good coil. Very reliable but I wouldnt wind it by hand like he did! It takes
hours!

>He uses 4 50Kv caps to do his. This
> brings me to guess that I would need 200Kv at  0.0088uF.
No. He uses 4 50KV caps in paralell. If he was using 200KV then that would
mean that they were connected in series. 50KV is overkill for any coil (the
biggest power supply ive seen is 30KV) If you built an MMC bank that is
rated at 12600V (9000*1.4 for peaks etc) then you will be along the right
track. 0.0088F is about right - maybee slightly more 0.01uF might be better.

> Let me know if I am
> wrong, but can I get some estimates on price and amount of caps? Also,
does
> anyone have a diagram of a MMC  type cap I can have/see?
Terry Fritz first designed the MMC bank I think - and the geek group seem to
be the main supplier of caps. I think that RS components do caps at about
30p each, and they are 1600v at 0.068uF. This would mean that you needed 1
string of 8 caps, or 2 strings of 16 caps to get the right rating. To work
out capacitance:
In series, add the voltages together and then multiply the capacitance
of 1 cap by 1 over the number of caps you are using, i.e. 8 in series is
1600*8=12800 and 0.068 * 1/8= 0.085.
In paralell you keep the voltage the same (i.e. 1600v) and you just add
up the capacitance.

For any other help, keep posting!!!

Jason

```