Swapping BS170 for JFETs?

[Steve Newton]

Any complications or kinks likely for using BS170s in place of A JFET?

Just scored 50 of them on ebay dirt cheap, have a couple of AMZ mosfet boosters to build for other people and I'm wondering what I can use the rest for.

[Ge_Whiz]

Well, MOSFETs and JFETs are rather different beasts.

Check out some of the circuits at www.runoffgroove.com for ideas - especially the Peppermill and the Matchbox (both thoroughly recommended).

[Hal]

fuzzface - (multiface) circuits are very versitilie when it comes to that.  Pop in anything that amplefies, and you're set!

[Steve Newton]

The only examples of Mosfet useage I have in books is either for power amps or showing simple uses of individual elements of a 4007 without much explanation. Nothing that will really help me to grok the use of them.

Anybody know of an online cookbook/technotes or whatever. Or am I doomed to making 50 boosters!!!!

For instance is it easy to use a BS170 as a voltage controled resistor? Do you just feed the control voltage into the Gate terminal via a resistor or does it need more involved circuitry?

[gez]

For instance is it easy to use a BS170 as a voltage controled resistor?

Yes, used it in many circuits.  Need DC bias on it (trimpot time).

Do you just feed the control voltage into the Gate terminal via a resistor

Yes, resistor not necessarily needed.   Whether you need additional circuitry depends on the circuit and what you're trying to achieve...