Re: Cap voltage - time

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-uswest-dot-net>" <m.j.watts-at-massey.ac.nz>

Fair alert/red flag........

On 21 Feb 01, at 19:22, Tesla list wrote:

> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> <Fucian-at-aol-dot-com>
> 
> In a message dated 2/21/01 8:38:03 PM Eastern Standard Time,
> tesla-at-pupman-dot-com writes: 
> 
> 
> >
> >    V = (i/C)*T volts 
> >
> > where 
> >
> >    i = current in amperes 
> >
> >    C = capacitance in farads 
> >
> >    T = time in seconds 
> >
> > Ed 
> >
> 
> 
> 
> BEGINER ALERT!BEGINNER ALERT!--hey can some one explain that formula
> to me?Im still getting used to computer graphics.Is it current divided
> by capacitance times time of charge equalls volts? 
> 
> matt

I see a number of equations popping up out there. Which one you use 
depends on which method of cap charging you use. 

Method 1: through a resistance - use the eqn given by someone for and 
RC time constant. (almost never used in coiling)
Method 2: through a constant current source - the eqn above. Also 
mostly doesn't apply in coiling with rare exceptions (see Marco's 
SMPS charger). A NST is more of a current limited source than a 
constant current one. It's compliance is not wonderful. In fact it is 
far closer to Method 3 (below) due to the NST's high leakage 
inductance.
Method 3: Charging through a reactor. Time taken is roughly time 
equivalent to 1/2 cycle at the resonant frequency of the L and 
primary cap if the source is also resonant at that frequency. 
Charging occurs over almost 1/2 a cycle. Assumes little resistance in 
the circuit compared with inductance.

Malcolm