13.2.3. Cutoff Region

Try these first

1. 1.

   What is the cutoff region in a MOSFET?

   Hint

   Think about the gate-source voltage in relation to the threshold voltage.

2. 2.

   Define threshold voltage (Vth).

   Hint

   This voltage is the turning point for current flow.

3. 3.

   What is the primary condition for a MOSFET to be in the cutoff region?

   • VGS < Vth
   • VGS = Vth
   • VGS > Vth

   Hint

   Remember what happens below the threshold voltage.

4. 4.

   True or False: The saturation region occurs when the drain-source voltage is very low.

   • True
   • False

   Hint

   Think about the behavior of current in saturation.

5. 5.

   A n-MOSFET has a threshold voltage of 1.5V. What would happen to the current if VGS is set to 1.2V? Illustrate this behavior using an I-V curve.

   Hint

   Plot points on a graph to illustrate the current remaining at zero until sufficient voltage is applied.

6. 6.

   Given an n-MOSFET with Vth=1V, calculate the drain current if VGS=3V and VDS=1V. What region of operation does this MOSFET fall into?

   Hint

   Review the equations for the triode operation and plug in your values.