FET configurations

Discussion in 'General Electronics Chat' started by Xufyan, Jun 2, 2011.

  1. Xufyan

    Thread Starter Member

    Aug 3, 2010
    Hello I have a question regarding JFET configurations,

    in JFET Fixed Biased Configuration when we find Zo , we set Vi=0 so Vgs and gmVgs equals to '0'.

    While in Self-Bias configuration when we set Vi=0 in order to find Zo , why gmVgs is not open circuited like Fixed Bias ??