# MOSFET Circuits: Which value of $V_S$ should I choose?

1)$$\ V_S \$$ potentially has two values. Which value of $$\ V_S \$$ should I choose?

2) Why?

3) What should I generalize from here about value of $$\ V_S \$$ that should be chosen while solving such problems?

• You need to choose Vs value which has a physical sense and ensures that the NMOS is conducting current (Vg - Vs > Vth).
– G36
Nov 2 '18 at 14:02