help on N-Jfet pls.....

[rx5]

Hi  Guys!!

need your help pls.... the following are the ONLY njfet available in my area... need infos on them....
---------------------------------
2N5458
"on" Resistance:
"off" resistance:
--------------------------------
2N3819
"on" resistance:
"off" resistance:
-------------------------------
2SK30A
"on" resistance:
"off" resistance:
------------------------------
J202
"on" resistance:
"off" resistance:
------------------------------


need them as audio switches for effects.............

thanks..



Ralph

[Joep]

Boss often uses the 2SK30A, so this will be a good one I guess.

A lot of datahseets are on www.fairchildsemi.com or try a Google search with "fet name" and pdf (so eg "2sk30a pdf")

[rx5]

Im only on a dial-up and it takes a lot of time to download a datasheet, ussualy 800Kb......

[brett]

Here's the forward transconductances of 3 of the 4 jfets you were after;
2N5458 1.5 to 5.5 mmhos
2N3819 3 to 6.5 mmhos
j202 >1 mmhos

From memory, I think that the conductance is negatively corellated with the Vgs(off), so go for low Vgs if you want high conductance.
Off resistances are, of course, huge.

Hope this helps.  Have fun.

[rx5]

thanks man....

needed those.....

-Ralph