How to bias a CS mosfet

It just struck me, Ian is Larkin in drag ;-) ...Jim Thompson

Bwahahahahahaha! ...Jim Thompson

Isn't the most pompous required to go first? Larkin, for once in your worthless engineering life, post a useful schematic that actually works. Have you no shame? Sorry, dumb question :-( ...Jim Thompson

And that is about as "brass tacks" as it gets!

Isn't it amazing how such a simple question can generate so much guff? At the risk of generating even more guff, here's my two penn'orth.

Correct me if I'm wrong, but if I have interpreted your circuit description correctly, the bias circuit attempts to set a constant current through the FET, which isn't quite what's needed.

We could have a flame war now, or shall we leave that nonsense to the septic tanks?

Richard

Yet you missed where I pinned him down on the cap stupidity, and all you have ever done in this group for the last four years is post pathetic insults. This is the first evidence that you ever knew a damned thing about electronics in this group, kook. And that can easily be doubted as well.

You are correct, the volt drop across the dran resistor would average constant so if Vdd fell substantially the MOSFET would be starved.

It is however an acceptible way of stabilising Vg for most practical purposes with a minimalist solution.

I've used it for a 2N7000 based clean boost guitar pre-amp and it works perfectly. The gain is massively bigger than a JFET stage, so I had to split the source resistor and only decouple the resistor that fed the bias stabilising transistor.

It was offered to the OP as a basic framework to adapt or build on but JF took exception to my helpful nature and the rest you know...................

How would they type the photos and drawings?

John

To demonstrate that you can design electronics, and not just cluck and whine about people who do.

I'm not holding my breath.

John

don't

Why does JF's bumchum brag that he has killfiled me, and then try to carry on a conversation? Senile, nasty old gits, both of them.

John

Or some equally bleak place in Texas.

John

I use LT Spice a lot. But I use other methods to design electronics, including thinking.

Speaking of monkeys pounding on typewriters, it's perfectly feasible to post gibberish as a Spice netlist. You do it now and then:

I don't know why you so revere Spice; maybe it's because you can't actually visualize or understand electronics, or do math past Ohm's Law.

No, after about the age of 10, I sort of took over. And I never hated them; they were nice, inoffensive, hard-working people who tried hard to take care of us, and give us opportunities they never had. What were your parent like?

I have always tended to not submit to authority, mostly by end-run or ignoring them or taking charge. Belligerence isn't very effective.

You and your bumchums insult my family, my wife and my daughter and my parents, because you are a foul and impotent creeps. And you are, as usual, firing blanks.

Intercede? You know almost nothing about electronics. All you do is whine.

John

He wants to actively bias the *drain* of a mosfet amplifier to Vcc/2. You seem to keep missing that point. You keep trying to bias the gate of a downstream fet to some fraction of Vcc, which makes no sense.

And you are using a huge number of parts to do it; two resistors would replace the hairball that you posted.

You don't understand this stuff.

John

Stalker tactics.

don't

He was responding to John, idiot, not you.

So, it is more like your BUNKUM.