[Amps] Capacitance Amount Formula

[Bill Fuqua]

The following is fine for single phase, one section capacitor input filter:
An Exact solution will provide slightly lower values of ripple voltage for 
a given capacitor. And
the ripple voltage in this  example is peak to peak not RMS. So what....
The capacitor you get off the shelf may have 10 percent tolerance at best to
"Plus 80 minus 20 percent".  Who cares?  Are you going to take into account
the varying load current for SSB mode, AB2 amplifier applications?

73
Bill wa4lav





At 11:43 AM 2/10/2003 +0000, Dr. David Kirkby wrote:
> > This is a ripple calculation based on the basic capacitor formula
> >
> >     I = C * dV / dT
> >
> > Let's say you want 3% ripple at 4 KV...that's 120V.  The capacitor charges
> > on each line peak, twice in each 60 Hz cycle, or 8.3 msec.  Rearranging
> >
> >     C = I * dT / dV
> >
> > Plugging in
> >
> >     C = 0.5A * 8.3 ms / 120V = 35 uFd
> >
> > jeff, wa1hco