Hero999
Banned
I'm toying with the idea of making a rail gun (just for fun I don't want to kill anyone) but I can't get my head around some of the formulae. Could someone please help me?
Discharge occurs in two separate phases, the initial discharge which is essentially the first part of a sinewave, then the freewheeling which is an exponential decay as the inductor's feild collapses causing power to be dissipated in D and R.
Firstly are my existing equations correct?
Phase 1:
[latex]f_0 = \frac {1}{2 \pi}{\sqrt{\frac{1}{LC}-\frac{R^2}{L^2}}[/latex]
[latex]v = V sin (\omega t) e^{\frac{-R}{2L}t}[/latex]
Does anyone know how to calculate i or even I?
I've worked out that if R = 0 then:
[latex]I = \sqrt{\frac{CV^2}{L}}[/latex]
However this isn't the case if I introduce R.
If I can calculate I then i should be easy.
[latex]i = I sin(\omega t)e^{\frac{-R}{2L}t}[/latex]
Phase 2:
I understand that this should be the same as the current in an inductor decaying through a resistor, but what about the voltage drop across D?
Please don't point be to a Wikipedia artical on LRC circuits, or differential calculus, because I've read them both and I don't fully understand either. I've touched on this stuff at college but the lecturer was poor and I didn't any point in learning it anyway so I scraped though with the lowest grad for that section and now I'd forgotton what little I knew.
However I don't what you to just give me the answer but how to come to the answer and no this isn't coursework.
Discharge occurs in two separate phases, the initial discharge which is essentially the first part of a sinewave, then the freewheeling which is an exponential decay as the inductor's feild collapses causing power to be dissipated in D and R.
Firstly are my existing equations correct?
Phase 1:
[latex]f_0 = \frac {1}{2 \pi}{\sqrt{\frac{1}{LC}-\frac{R^2}{L^2}}[/latex]
[latex]v = V sin (\omega t) e^{\frac{-R}{2L}t}[/latex]
Does anyone know how to calculate i or even I?
I've worked out that if R = 0 then:
[latex]I = \sqrt{\frac{CV^2}{L}}[/latex]
However this isn't the case if I introduce R.
If I can calculate I then i should be easy.
[latex]i = I sin(\omega t)e^{\frac{-R}{2L}t}[/latex]
Phase 2:
I understand that this should be the same as the current in an inductor decaying through a resistor, but what about the voltage drop across D?
Please don't point be to a Wikipedia artical on LRC circuits, or differential calculus, because I've read them both and I don't fully understand either. I've touched on this stuff at college but the lecturer was poor and I didn't any point in learning it anyway so I scraped though with the lowest grad for that section and now I'd forgotton what little I knew.
However I don't what you to just give me the answer but how to come to the answer and no this isn't coursework.