Quote from the 2008 ARRL handbook power supply section:
"percent ripple is the ratio of RMS value of the ripple to the dc value in
terms of percentage".
As RMS does the same amount of work as dc does it would make sense to use
RMS as a comparison.
73
Gary K4FMX
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On Behalf Of Alex Eban
> Sent: Saturday, March 27, 2010 6:50 AM
> To: dezrat1242@yahoo.com; amps@contesting.com
> Subject: Re: [Amps] ripple in B+ supply.
>
> Since you cope with DC voltages, it makes sense to employ something
> close
> for the ripple and that average voltage. Fortunately, for the triangular
> wave form, the average is 1-3 of the peak to peak and it usually
> expressed
> as a percentage of the DC output value. RMS has nothing whatsoever to do
> with it. It was the method used by power supply designer for years.
> Alex 4Z5KS
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On
> Behalf Of Bill, W6WRT
> Sent: Thursday, March 25, 2010 7:15 PM
> To: amps@contesting.com
> Subject: Re: [Amps] ripple in B+ supply.
>
> ORIGINAL MESSAGE:
>
> On Thu, 25 Mar 2010 06:03:37 -0700, "Jim Thomson" <Jim.thom@telus.net>
> wrote:
>
> >## Bill, EVERY arrl book I have, [back to 1960] plus Orrs'
> >books always references ripple to RMS. Every ARRL formulae
> >is referenced to RMS.
>
> REPLY:
>
> RMS is a useful piece of info, no argument there, but anyone who is
> seriously evaluating a PS will want to look at the output with a scope
> to
> see if there are any "funnies" going on such as the presence of
> excessive
> RF, missing or seriously unequal half-cycles from an FWB, etc.
>
> Like I said, I am probably prejudiced. I was brought up in electronics
> by
> folks who taught me that a scope is more useful than a meter, and I
> still
> believe that. Of course it is best to have both, but in cases involving
> AC
> measurements, I reach for the scope first.
>
> I worked at Tektronix for ten years too. No doubt that had some impact.
> :-)
>
> 73, Bill W6WRT
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