function I = Cl(V)
global G_Cl1 G_Cl2
% 
% Two resistors in parallel to generate a mild IV-characteristics (of the
% Cl-channel
% Need G_Cl2 < 0 < G_Cl1 and G_Cl1 + G_Cl2 > 0 is small 
%

I1 = G_Cl1*V; % parallel resistor 1
I2 = G_Cl2*V; % parallel resistor 2
I = I1 + I2; % equivalent resistor by Kirchhoff's Laws.