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}]