Re: capacitor charge rate/power

["Barton B. Anderson" <tesla123-at-pacbell-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Pholp, 
  

Tesla list wrote: 

>
> Original poster: "Pholp Smiff" <kawanze-at-hotmail-dot-com> 
>
> can anyone give me a formula as to how long it takes to charge a capacitor 
> depending on size and power? i.e.: using a 12kv-at-60mA transformer, how long 
> would it take to charge a .1mF capacitor?


CP charge time in an AC circuit is transfomer impedence x Cp x 5. 
Z x Cp x 5 = 200,000 x 0.1uF x 5 = 100ms for "full" charge. 

>
> Can someone tell me and show me 
> the math behind it? And how much power is actually stored and let out in a 
> discharge.


The term is "energy" stored in the cap rated in joules. 
energy in cap = 1/2 x Cp x Vp^2 = .5 x .1uF x 12kv^2 = 7.2 joules 

BTW, a .1uF cap is pretty big for a 60mA transformer. If you set a gap to fire
once every half cycle (120 bps), then you would only charge this cap to 20%
(3.3kv) and the energy stored would be way down to 0.58 joules. Obvisously, the
discharge rate would be set much less than 120 bps to charge the cap to a
decent voltage. A more realistic cap size would be .01 or .02uF for the
transformer (or you could build a big coil and use a big transformer for this
cap size). 

>
> Also i'd like to know how to determing the size of a bleeder 
> resistor for capacitors.


Terry covered that in his post. 

Hopefully this helps. If anythings wrong there, hopefully someone will correct
me. 

Take care, 
Bart