Jfet

In a JFET why does the Vgs vs Id curve change when Vds is changed?? That curve is poltted for constant current region right???in the constant current region Id or Vgs doesn't depend on Vds..then why is above graph changing when Vds is changed???

If anyone knows an explanation pls post it...
thank u...

An ideal device would not change, but a real device has a finite output impedance. This causes a small change in drain current with voltage at a given gate-source voltage.

I get it..Thanx very much