Tom said:
>Actually the ESR of the AC source, the load resistance, and
the rectifier type determine the ripple and dynamic
regulation.<
But is the requirement ripple reduction, or the ability of the HV supply to
hold up for short peaks?
The capacitor releases 0.5 .C.Ve2 (one half C times V squared) joules where V
is the drop in the HV. That's also equal to coulombs/sec, which is I times t.
So you can equate these to figure how much capacitance is needed for a given AC
supply impedance and frequency for an amount of ripple. But if you're talking
of allowing a different voltage drop over a 50 millisecond speech peak, you get
a different answer, and that's where a big capacitor holds up better. It also
can show up a lot better on a 2 tone test as the tones get closer together in
frequency, although I think we all agree that a 2 tone test is not the be-all
and end-all of test methods. But in terms of ripple, the bigger the ESR, the
sooner you get to the stage of diminishing returns.
73
Peter G3RZP
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|