3.6. Parameters of JFET

Try these first

1. 1.

   What does the drain current (ID) indicate?

   Hint

   Think about what controls the current in a JFET.

2. 2.

   What does IDSS represent?

   Hint

   Consider the scenario when no voltage is applied at the gate.

3. 3.

   What is the maximum drain current represented as in JFETs?

   • ID
   • IDSS
   • VGS(off)

   Hint

   Remember the definition of maximum drain current.

4. 4.

   True or False: The cut-off voltage is the gate-source voltage at which the drain current stops.

   • True
   • False

   Hint

   Think about when the JFET switches off.

5. 5.

   Design a JFET amplifier with a required gain of 20, given that IDSS is 10 mA and VGS(off) is -4V. Determine the necessary transconductance (gm).

   Hint

   Identify how gm relates to required gain and plot bias accordingly.

6. 6.

   A specific JFET exhibits a cut-off voltage of -2V. If a voltage of -1.5V is applied, discuss the expected behavior of the JFET.

   Hint

   How does VGS compare to VGS(off)?