% 
% Forward Euler on a Passive Sphere
%
%  usage   feps(dt,Tfin)
%
%  e.g.    feps(0.01,40)
%

function feps(dt,Tfin)

VCl = -68;	% mV
A = 4*pi*1e-6;	% cm^2 patch area
Cm = 1;         % micro F/cm^2
gCl = 0.3;      % mS/cm^2
tau = Cm/gCl;   % ms

Nt = round(Tfin/dt);
v = zeros(Nt,1);
t = zeros(Nt,1);
v(1) = VCl;

for j=2:Nt,

   t(j) = (j-1)*dt;

   Istim = (t(j-1)>2)*(t(j-1)<22)*1e-5;    % 10 pA 20 ms pulse

   v(j) = (1-dt/tau)*v(j-1) + dt*(VCl/tau + Istim/A/Cm);

end

plot(t,v)
xlabel('t  (ms)','fontsize',14)
ylabel('V  (mV)','fontsize',14)