[ARC5] Back to basics: Capacitor breakdown voltages

[Dennis Monticelli]

Be careful with the voltage rating of the shunt resistors.  Ordinary
resistors cannot handle 1000V.  Check specs first.

Dennis AE6C

On Sun, Jan 24, 2016 at 7:46 PM, WA5CAB--- via ARC5 <arc5 at mailman.qth.net>
wrote:

> 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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