plotting the graph, help me~~

The above graph is the purpose that i want.

The below is the code and it has errors. Whats the problem? Please suggest the code. Thanks

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W=40;

Vth=0.45;

Leff=0.15;

k=4.255*(10^-4)*(W/Leff);

lambda=25*10^-5;

Vgs=linspace(0,2);

vds=[0.2 1 2];

m=length(Vgs);

for k1 = 1:numel(vgs)

for i=1:m

if vgs(k1) < Vth

current(k1,i)=0;

elseif Vds(i) >= (vgs(k1) - Vth)

current(k1,i)=0.5* k * ((vgs(k1) - Vth).^2);

elseif Vds(i) < (vgs(k1) - Vth)

current(k1,i)= k*((vgs(k1)-Vth)*Vds(i) - 0.5*(Vds(i).^2));

end

end

end

figure

plot(Vgs,current, 'LineWidth',1.5)

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error: 'current' undefined near line 1, column 1

error: 'vgs' undefined near line 1, column 1

Answer 1

[Alan Stevens]

You had a few mismatches between vgs and Vgs. Matlab is case sensitive. Try

W=40;
Vth=0.45;
Leff=0.15;
k=4.255*(10^-4)*(W/Leff);
lambda=25*10^-5;
Vgs=linspace(0,2,5);
Vds=[0.2 1 2];
m=length(Vds);
for k1 = 1:numel(Vgs)
for i=1:m
    if Vgs(k1) < Vth
        current(k1,i)=0;
    elseif Vds(i) >= (Vgs(k1) - Vth)
        current(k1,i)=0.5* k * ((Vgs(k1) - Vth).^2);
    elseif Vds(i) < (Vgs(k1) - Vth)
        current(k1,i)= k*((Vgs(k1)-Vth)*Vds(i) - 0.5*(Vds(i).^2));
    end
end
end
figure
plot(Vgs,current, 'LineWidth',1.5)