JFETs as clippers, questions.

[Nick C.]

I would like to try using JFETs as clippers in a feedback loop.

I 'm not sure how to hook them up, but I have seen 2 methods:
1. Connect gate and source together drain is the other side.
2. Use either the gate and source or gate and drain, ignoring the third leg in each case.

This differs from using a mosfet, gate and drain together and connect source to a diode. I've tried this and it works pretty well.

Will a JFet work? Will they be a smoother clipper than a typical Si diode? What would the knee voltage be?

Thanks in advance.

Nick

[DougH]

Search is your friend: http://www.diystompboxes.com/smfforum/index.php?action=search2

[WGTP]

http://www.diystompboxes.com/smfforum/index.php?topic=38581.0

One of my favorites. 

[suprleed]

Very interesting...time to break out the breadboard.

[Nick C.]

The link above is a very good one. A lot to digest on this subject.

I played around with some jfets last night and found that the source and gate make a diode if I ignore the drain. I was disappointed that it only measured .7v as I was hoping for higher. I didn't try it in my circuit yet.

What I'm trying to do is limit the op amp clipping in a Dist+ type, I figure I need a diode(s) that will clip (softly) before hitting the 4.5v rails. Trying to avoid using six per side or LED's. What has been done in the past? What is a rail to rail op amp?

Nick