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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