function input = IED_function(tspan,u0)
    tr = 5e-3;
    td = 2.5e-3;   

        
    input = zeros(size(tspan));
    for i=100:length(tspan)
            
       input(i) = u0*(exp(-tspan(i-99)/tr)-exp(-tspan(i-99)/td));
    end
    
    

       

end