getting error in for loop

Array indices must be positive integers or logical values.

Error in Untitled4 (line 27)

Idsat(i)=r1*(Vgs-(r2)+Vds(i));

for i=0:length(Vds)

Idsat(i)=r1*(Vgs-(r2)+Vds(i));

end

[Sam Chak]

Have you checked if your array indices are positive integers or logical values?

Answer 1

[Torsten]

Loop indices don't start at 0, but at 1 in MATLAB:

for i=1:length(Vds)
    Idsat(i)=r1*(Vgs-(r2)+Vds(i));
end

instead of

for i=0:length(Vds)
    Idsat(i)=r1*(Vgs-(r2)+Vds(i));
end

Answer 2

[Nudrat Sufiyan]

Thanks , but it still showing error.

can you please check my code once

clc;

m=0.23; %#1%

q=1.6e-19;

Nd=5e18;

d1=22e-7;

d2=1e-7;

a0=3.189e-8;

a1=(-0.077*m+3.189)*1e-8;

c13=(5*m+103);

c33=(-32*m+405);

e33=(0.72*m+0.73)*1e-4;

e31=(-0.11*m-0.49)*1e-4;

fis=1.4*m+0.87;

deff=23.01e-7;

detaEg=6.13*m+(1-m)*3.42-m*(1-m)+(m-1)*3.42;

detaEc=0.7*detaEg;

EA=(8.9-0.4*m)*8.85e-14;

Eoff=EA+((e33)^2)/c33;

EF=2.1;

sigema=((-m*(5.2e-6))+(2*(a0-a1)/a1)*(e31-e33*c13/c33)*1e-4);

Ppz=(2*(a0-a1)/a1)*(e31-e33*c13/c33)*1e-4;

r1=q*EA/deff;

r2=fis-(EF-(detaEc+q^2/EA*sigema^2*d2))/q;

Vgs=-2;

Vds=0:0.01:0.8;

for i=1:length(Vds)

Idsat(i)=r1*(Vgs-(r2)+Vds(i));

end

xlabel('vds');

ylabel('Idsat');

plot(Vds,Idsat)

[Nudrat Sufiyan]

As, I want to plot Idsat and Vds curve.

[Torsten]

The code works fine for me.

[Nudrat Sufiyan]

for me it's showing an horizontal line. Can you please send the output

[Torsten]

r1 = 5.420307692307692e-26
Vgs = -2
r2 = -7.731499999999999e+18

Thus Vds won't change anything if you have in mind how large r2 is.

[Nudrat Sufiyan]

As vds must varies with Ids. For this what I need to change in the code.

[Torsten]

It varies, but you don't see it in the plot since r2 = -7.731499999999999e+18.

Do you understand what I mean ?

If you plot a variable

T = 100000000 + 0:0.01:0.8

you won't see the 0:0.01:0.8.

[Torsten]

@Nudrat Sufiyan comment moved here

It means I should change the value of r2