Re: capacitor equation solution not working
- To: mathgroup at smc.vnet.net
- Subject: [mg119790] Re: capacitor equation solution not working
- From: Dana DeLouis <dana.del at gmail.com>
- Date: Wed, 22 Jun 2011 07:06:05 -0400 (EDT)
... I[t_]:= If[t<10||t>60,0,1]
Hi. Just 2 cents for an alternative.
For a signal pulse, sometimes I'll remember it as follows:
What we have...
If[t<10||t>60,0,1];
FourierTransform[%,t,w]
(E^(35 I w) Sqrt[2/\[Pi]] Sin[25 w])/w
InverseFourierTransform[%,w,t]
1/2 (Sign[60-t]+Sign[-10+t])
Plot[%,{t,0,100}]
Or transformed into something like this:
f[t_]:=UnitStep[t-10]-UnitStep[t-60]
f[t_]:=UnitStep[-(t-10) (t-60)]
= = = = = = = = = =
HTH : >)
Dana DeLouis
On Jun 17, 12:09 am, "J and B" <noslow... at comcast.net> wrote:
> I am trying to solve a very simple circuit, one that has only a capacitor in
> it. What am I doing wrong? The final graph should show that the capacitor
> has discharged, but its staying constant. I have current starting at t=10
> and ending at t=60.
> I hope I have used the correct way to put in my code, I am using a new
> computer and I having trouble with my email program. Any advice would be
> appreciated.
>
> Thanks
>
> My code.
> I[t_]:= If[t<10||t>60,0,1]
> Plot[i[t],{t,0,100}]
> Eq=v'[t]==i[t]/c
> c=1;
> Soleq==v[t]/.NDSolve[{eq,v[0]==0},v[t],{t,0,100}],[[1]]
> Plot[soleq,{t,0,100}]