[ARC5] Back to basics: Capacitor breakdown voltages

[WA5CAB at cs.com]

Ideally, voltage ratings of capacitors in series add.  Although it only 
comes close to working with capacitors when both are both the same capacitance 
and voltage rating.  So in order to replace a single 1 ufd 3 KV capacitor 
with 1 ufd 2 KV units would require four of them and would result in a 1 ufd 4 
KV capacitor assuming all four were close to identical.  To replace all 
three of the originals would require twelve.  Not an economical solution.

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480

In a message dated 01/24/2016 20:14:35 PM Central Standard Time, 
radio-tuber at att.net writes: 
> OK, I can calculate series/parallel combos, but how does the breakdown 
> voltage work? 
> 
> My BC -375 has a leaky trio of 1uF oil filled bypass caps that have 3kV 
> ratings. Mouser has pricey ($20) 1uF and .47uF units rated at 2kV. How does 
> that breakdown work?
> 
> One shorted, and the plate current meter went up like a sparkler. Other 2 
> are making my PSU lug down, B+ dropping to 900 from the usual 1100 VDC it 
> idles at. I get 800 while transmitting instead of 1kV like it usually does. 
> 
> Cheers!
> Jim K6FWT
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