Determining operation regions for three NMOS transistors with Vtn = 0.4V

[ddta1050]

Homework Statement

Vtn = 0.4V

NMOS1
Drain = 2.5V
Gate = 1.9V
Source = 0V

NMOS2
Drain = 0.5V
Gate = 2.2V
Source = -2.3V

NMOS3
Drain = 0.5V
Gate = 0.9V
Source = -2.5V

Homework Equations

The Attempt at a Solution

NMOS1
Vgs = Vg - Vs = 1.9V
Vgd = Vg - Vd = -0.6V
Vgd < Vtn and Vgs > Vtn
Saturation Region

NMOS2
Vgs = Vg - Vs = 2.2 - (-2.3) = 4.5V
Vgd = 2.2 - 0.5 = 1.7V
Vgd > Vtn and Vgs > Vtn
Triode/Linear/Ohmic region

NMOS3
Vgs = 0.9 - (-2.5) = 3.4V
Vgd = 0.9-0.5 = 0.4V
What region is the NMOS operating in if Vgd is equal to Vtn?

 

[rude man]

Hint: you're on the hairy edge, so to resolve the issue use the equations defining which operating region you're under.