FET Fundamentals Unit 3 – JFET Amplifier
UNIT 3 – JFET AMPLIFIER
UNIT OBJECTIVE
At the completion of this unit, you will be able to describe the operation of a JFET voltage
amplifier by using dc measurements and observed waveforms.
UNIT FUNDAMENTALS
JFET amplifiers must be biased correctly to:
- establish dc voltages around which undistorted sine waves can occur.
- stabilize circuit performance against wide device variations between JFETs of the same type.
In common source amplifiers, two basic methods of bias are used:
- fixed bias(gate bias)
- source bias (self bias)
Source bias improves circuit stability and requires only one power source, VDD.