[R-390] 6080 in place of 6802 - RMS ???

[David Wise]

> From: Roger L Ruszkowski

<snipped for brevity>

> With the tubes and diode all in series.
> Apply twice the voltage across the proper filament
> resistance for 1/2 the time and the power comes out
> correct.

With all due respect, Roger, for what it's
worth, I'm weighing in with those who say
it's wrong.  This has been hashed hard, but
we haven't exhausted the ways of saying the
argument.  Let me try.

Your error above (and it's subtle if you
read it quickly) is in thinking that power 
is proportional to voltage.  It's not, it's
proportional to voltage squared.  So, if you
apply twice the voltage for half the time,
what you get is four times the power for half
the time, which is the same as twice the power
all the time.  Those 6080s that went for years,
were sizzling at 8.8V (i.e. sqrt(2) * 6.3V).
That they went the distance is a credit to
the robustness of their design, but they
being abused.

> 
> The AC is 1/2 wave rectifed by the diode.
> The voltage is pulsed.
> The current is pulsed.
> The filament resistance limits the power flow.
> The average results works.
> 
> Diddle this math all day. But other people report
> their circuits have worked for years.
> 
> Barry,
> 
> Where did you miss the diode in this thread?
> 
> Roger KC6TRU.
> 
> 
> 
> 
> 
> 
> 
> 
> _______________________________________________
> R-390 mailing list
> R-390@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/r-390
>