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If I have two identical capacitors and I connected them in series/parallel what would happen?

Take 10,000uF and 100v, Does that double the voltage or the capacitance? I want to end up with a capacitor bank of around 400v with a capacitance of minimum 8,000uF. So what I'm getting at is what can i change around in terms of capacitors and to what effect. Thanks : D

  • BTW, I'm going for a coilgun here

EDIT:
  • Also, if i'm building a capacitor bank for a coilgun, would i be going for the max capacitance or the max voltage?

17 answers
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May 24, 2009. 11:41 PMfrollard says:
if you put them in series, you'll get double the voltage, but 1/4 the capacitance - because they interfere with each other. If you put them in parallel you'll get twice the capacitance and 1:1 on the voltage. Why does the capacitance go down? because a capacitor as it charges starts to resist the flow of power thru it. When fully charged, there is no flow because the internal voltage directly opposes the input. 2 in series kind of cancel one another out - but since there are 2 you can handle twice the voltage (half each)
May 25, 2009. 2:55 AMfrollard says:
http://www.kusashi.com/series-capacitors.php

if for example you use 2 1000uf caps you get 500 total. you would expect 2000.

its the inverse of the sum of the inverses...or something

yeah...

1/( (1/1000) + (1/1000) ) = 500
May 25, 2009. 5:20 AMfrollard says:
none that you wouldn't see in any capacitor-using circuit - take the same considerations you'd have regarding single capacitors - storing oodles of power and zapping you, etc.
Jun 1, 2009. 9:11 PMvolthead says:
you have to be careful putting caps in series as if the ESR of the caps is higher than the load they will be ruined
May 24, 2009. 4:34 AMdilandou says:
A quick read through this page should help you out.
May 24, 2009. 6:24 AMdilandou says:
Basically if you want a higher voltage you string capacitors together in series. If you want higher capacitance you put them in parallel.
May 24, 2009. 6:58 AMlemonie says:
Notice that link says "Two or more capacitors are rarely deliberately connected in series in real circuits" - you'd be best sourcing the right caps' if you can. L
May 25, 2009. 8:13 AMlemonie says:
Good luck, I came across the phrase "supercapacitor" yesterday - they sound well-good (though probably well-expensive...) L
May 24, 2009. 2:39 AMsboy365 says:
Sorry I can't help, don't know much about capacitors

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