Re: Cap voltage - time ???!!!author

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

Original poster: "kevin wilson by way of Terry Fritz <twftesla-at-uswest-dot-net>" <thebiggiantkevin-at-hotmail-dot-com>

First thank you all for your help, but... I’m actually more confused now 
then when I posted the question :-/ There seems to be different equations 
for different circumstances. So I'll try to be more specific. This equation 
will be used in a program I’m writing to find the voltage across the primary 
cap after a given time (time determined by a rotary gap). I have no 
experience with rotary gaps, and I’m just building by first coil now. 
(Beginner Alert!!) If I can get this formula straightened out, then the 
program should be done soon. I plan to post it so everyone who wants it can 
get it for free. Thanks again, Kevin

Here are the equations that have been posted so far;

1- When charged from a constant current source, V = I * T/C
(I dont think I use this one)

2- V = (i/C)*T volts where i = current in amperes C = capacitance in farads 
T = time in seconds, from Ed


3- When charged from a constant voltage source through a resistor
V = Vcharge * (1-exp(-T/(R*C)) where exp(x) is e^x, where e = 
2.71828459045....Units: Ohms, Volts, Farads(!), Seconds
(I couldnt get this one to work)

4- For resonant charging from a sinusoidal voltage using a synchronous 
rotary gap the cap voltage is: V = [ E / 2 ] [ sin(wt) - wt.cos(wt) ] where 
E is the peak volts available from the transformer = 1,414 x the rms volts, 
w = 2.pi.f, f is the mains frequency, and sine and cosine are in radians. 
Multiply the (wt) (but not the wt without brackets) by 57,296 if you want to 
work out the sine and cosine in degrees
(This one looks good, but I havnt tried it yet)
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