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Re: MMCs and cap calculations?
Original poster: "Dr. Duncan Cadd by way of Terry Fritz <twftesla-at-uswest-dot-net>" <dunckx-at-freeuk-dot-com>
>Original poster: "Nathan Ball by way of Terry Fritz
<lots of snips>
>The caps say both 563 J and 1.6 KVDC on them, so using the equation
>(Joules) = 1/2CV^2, I get ...440uF each?
>I just found digikey and recalled that they were .056uF apiece, which
>a LOT more sense and fits what I remembered about my capacitor.
>What's up? Is it me, the caps or the physics book?
I think it's cap nomenclature which has got you. If the caps say 563J
I would bet it means 56 x 10-3 (microfarads) and J is a tolerance
figure. Simply a question of deciphering the manufacturer's code.
First two figures (56) are the cap value, third figure ([-]3) is the
multiplier, fourth (J) is tolerance (or could be temperature
coefficient, so many parts per million per degree C; J generally means
5% tolerance or 120ppm temp coefficient).
In any case, as you calculated, 563J of energy means a cap of 440uF
and a 440uF 1,6kV cap is going to be fairly big (unless you get them
the place I got my interoscitor ;-)
Hope this helps.