[Amps] How much electrolitic for a HV supply ?

[Peter Chadwick]

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