FET Fundamentals Unit 3 – JFET Amplifier
Exercise 1 – DC Operation
EXERCISE OBJECTIVE
When you have completed this exercise, you will be able to measure dc operation voltages by
using a JFET amplifier. You will verify your results with a multimeter.
EXERCISE DISCUSSION
- A 0V biased N-channrel JFET is used in this experiment.
- At 0V bias, the drain current (ID) is at saturation and symbolized as IDSS.
- Drain current varies over a wide range when the device is biased at 0V, to restrict this range a
self, or source, bias configuration is utilized. - Gate current (IG) is approximatly zero when a JFET is operating properly. Therefore, the gate
is at common (0V) through RG. - Gate to source bias voltage (VGS) is a negative value and establishes the dc bias point at
which the JFET will operate. - Bias voltage (VGS) magnitude is determined by the value of ID flowing through RS.