Date   : Tue, 30 Jun 2009 08:37:22 +0100
From   : jim@... (Jim Hearne)
Subject: 32016 2nd Processor PSU smoking...

Yes, i agree, if it was part of a filter it would change the filtering 
frequency.
But in this case i believe we are talking about the capacitor that is 
stuck across the mains input to stop switching noise from the psu 
getting back into the mains system.
In this situation a slightly higher capacitance would work just as well.

Jim


Sprow wrote:
> In article <4A48793F.6070308@...>,
>    Jim Hearne <jim@...> wrote:
>   
>> For this application a larger capacitance (than the original) capacitor 
>> would work fine, a smaller one would have less filtering effect.
>>     
>
> In conjunction with an inductor (making a 2nd order filter) "less" is
> probably the wrong word. It would move the resonant frequency, quite
> possibly to a frequency where no noise existed anyway.
>
> eg. a 50kHz switcher might tune L & C to be at 50kHz
> Doubling C would move to 25kHz (where there was no energy) and let through
> all the nasty 50kHz onto the line.
>
> So I stick to my original comment:
>
>   
>>>>> What purpose would replacing them with the wrong value serve, other 
>>>>> than to fill the holes on the PCB?
>>>>>           
>
> Sprow.
>
>
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