[Test-Equipment] Question about series/parallel capacitors

[Ron]

Connecting capacitors in series is NOT a good idea, 
because at each point in time, each cap leakage 
will be different, so the voltage across each cap 
in the string will be different and could easily 
be higher than the rated voltage for that cap.
Voltage equalizing resistors in parallel with each 
cap will be seen by the circuit as cap leakage, that
in many applications (including bridges) is not 
acceptable. 

The solution is a single cap, of the required 
characteristics (capacitance, tolerance, temperature 
dependence, voltage, max leakage, etc.).

-- Ron




--- On Fri, 5/13/11, Barry <n4buq at knology.net> wrote:

> From: Barry <n4buq at knology.net>
> Subject: [Test-Equipment] Question about series/parallel capacitors
> To: test-equipment at mailman.qth.net
> Date: Friday, May 13, 2011, 6:59 PM
> I need a 0.5uF capacitor that's
> capable of handling 600VDC.  I have several 0.5uF that
> are rated at 250V so I plan to connect them in
> series/parallel to get 0.5uF at 750V.
> 
> The question I have is does it matter how these are
> connected?
> 
> I have the choice of:
> 
> A. Connecting three sets of three capacitors each in
> parallel to produce 1.5uF and then connecting the three sets
> in series yielding 0.5uF.
> 
> or
> 
> B. Connecting three sets of capacitors in series and then
> connecting the resulting 1/6uF capacitors in parallel to
> again make 0.5uF.
> 
> 
> Both methods will give me 0.5uF but it I'm wondering if one
> way has any advantages.
> 
> Any thoughts?
> 
> Thanks,
> Barry - N4BUQ
> 
> 
> 
> 
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