
Re: capacitor equation solution not working
Posted:
Jun 17, 2011 5:06 AM


> > On Fri, Jun 17, 2011 at 12:09 AM, J and B <noslowski@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 >> >> I did not check the rest , but fixing two formatting errors can > be helpful. > > > > My code. > > I[t_]:= If[t<10t>60,0,1] > > Plot[i[t],{t,0,100}] (* you use different letters for the current, iand > I; btw, I is reserved for the imaginary unit *) > > *Eq*=v'[t]==i[t]/c > c=1; > > > > c=1; > > Soleq==v[t]/.NDSolve[{*eq*,v[0]==0},v[t],{t,0,100}],[[1]] > > Plot[soleq,{t,0,100}] > ( **Eq* and *eq* are also different *)
Btw, your circuit without a resistor is "short": the capacitor will discharge instantly. Be also aware that the derivative of a step function is expressed though the so called deltafunction which must be handled with extreme care.
Best MP

