# passive membrane with step function current: passive.ode
dV/dt = (1000*(E-V)/R_M + I_0*f(t))/C_M
V(0)=-70
# I in microamps/cm^2 C_m in microfarads/cm^2 R_M in Ohm cm^2 E in mV
# t in msecs
parameter R_M=10000, C_m=1, I_0=2, E=-70
parameter t_on=5, t_off=10
# define a pulse function
f(t)=heav(t_off-t)*heav(t-t_on)
# track the current
aux ibar=f(t)*I_0
done