On Behalf Of Jim Thomson
> Sent: Tuesday, March 23, 2010 9:36 PM
> To: amps@contesting.com
> Subject: [Amps] ripple in B+ supply
>
> ORIGINAL MESSAGE:
>
> On Mon, 22 Mar 2010 19:31:09 -0700, "Jim Thomson" <Jim.thom at
> telus.net>
> wrote:
>
> >
> >## after actually doing it now for 3 yrs... I'd say you want a MAX of
> 1% ripple.
>
> REPLY:
>
> Peak to peak, RMS or what?
>
> 73, Bill W6WRT
> ### RMS. Ripple measurements and calcs have been RMS since day 1.
> If you want to do it in peak... or peak to peak.. that's fine too. Just
> don't trycomparing peak to peak..... to RMS. later... Jim VE7RF
Not that it is a big deal Jim, but what are you using to measure that RMS
voltage with? Note that it is not a sine wave.
73
Gary K4FMX
## One easy method is to just uses a Fluke 87 [true rms dvm] and put it across
the 1st hv lytic... at the cold end of the string. Put meter on AC volts. The
fluke has
internal blocking caps.. so just reads the AC component.
2nd method is to just use the latest version of duncans PSUD. Then drive
the amp to normal plate current,with a CXR. 3rd method is to use a scope
across the 1st cap. 4th method is to use some of the formulae in the various
books. The results are all extremely close..regardless of method used.
## ripple is proportional to filter C. Triple the filter C.. and ur ripple
is now
1/3.
## a drake L4PS.. with a 25 uf filter + 800ma load, works out to aprx 3%
ripple.[rms],
which was high-tech....in 1964.
later... Jim VE7RF
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