For this transistor circuit, I have drawn in my points and estimated Vgs on the Shockley Curve; But when calculating Vgs mathematically (Vgs= Vg-Vs) to check, I get 0V-5.5V= -5.5V (Vg always=0V). That is terribly off from my -1.54V Vgs value estimated at the bottom of my Shockley curve. I though the Vgs values from curve and calculation are supposed to be slightly the same? Any help?

Thanks guys!

 

also, if Vds= Vd-Vs, and is to always be positive, why am i getting 3.5v-5.5v= -2?

 

I have Id=2.74mA and Vgs=-2.48V

 

i guess im just not seeing how you derive that

 

\(I_D=I_{DSS}(1-\frac{V_{GS}}{V_P})^2\)

Must satisfy

\(V_{GS}=3-2000I_D\)

Where ID is in ampere.

I substituted the second relationship into the first and solved for ID, given IDSS and VP.