Pinch off values

[Tony Allgood]

Juergen>what you really want to match is the symmetry of your FETs in
your circuits.

Hi all,

I wanted to find the Vp for the 2SK30A-O and compare it to a 2SK30A-Y. I
tried the grounded source follower method and got such low values, I
became suspicious. When I then looked at Id=0, I found a more reasonable
result. Vp=1.5V or so for those two devices, the O type being generally
a little lower. Of course, the follower method was more suitable for my
requirement, which was to find the offset on a source follower! For the
TB303 VCO you need a very low offset, since the signal you are buffering
goes very close to the posistive supply. Now you know why other clones
don't sound like a TB303. :-)

Regards,

Tony Allgood  Penrith, Cumbria, UK

Walsh synthesiser, SuperLadder, TB303 clone and rack mounted filter

http://www.techrepairs.freeserve.co.uk/projects.htm