43. FET Common Source Amplifiers

The JFET Common Source Amplifier is one of the most used amplifier configurations in the world. It's large current gain, modest voltage gain, and impedance matching capabilities makes it very versatile. This video introduces the JFET CS, covers some of the equations needed to characterize them and, of course, an experiment to tie theory and application together.

[@Justsquareenough]

thank you! none of the books or articles ive read teach this method for arriving at gm. very helpful.

[@ats89117]

Thanks for the excellent video. The alternative to using an AC source resistance, which significantly reduces gain and increases noise, is to match JFETs. Of course matching transistors is a royal pain in the butt, but the potential performance gains are very high.

[@TomLeg]

@19.33 you say 3199 umhos * 1.61K is about 9. Surely you mean to say it's about 5 (5.09)

[@trevorvanbremen4718]

Nope, the 9 is 'correct'...
The problem is that the 3166 should ACTUALLY be 5625 on the prior slide (7500 * (1 - (2/8)))
Redo the calculation at 17:13 and you will see what I mean.