Quoting from Volume III, Chapter 5, Part 4 (link):
"...the saturation (non-horizontal) portion of a JFET's characteristic curve is sometimes referred to as the ohmic region."
Equating saturation portion of the FET characteristic curve with ohmic region would be confusing, if not inaccurate, since most textbooks actually refer to the region where the drain current nearly independent of the drain source voltage (the horizontal portion of the curve) as saturated region and the ohmic region as non-saturation/linear/triode region. The opposite!
In saturation region, the drain current is nearly independent of the drain-source voltage (hence the notion of saturation) and the relationship of VDS > VGS - VTH holds true.
In linear or ohmic region, the drain current does depend on, and varies linearly with, the drain-source voltage and the relationship of VDS < VGS - VTH is true.
I realise that this naming convention is confusing and counter-intuitive, especially because when a FET switch is fully on (where the drain-source voltage is saturated w.r.t drain current) we call the FET switch in saturation, although it is actually operating in linear/non-saturation/triode/ohmic region.
Also, the fact that the naming conventions of equivalent regions in BJT characteristic curve is the opposite (ohmic -> saturated, saturated -> active) doesn't help either!
"...the saturation (non-horizontal) portion of a JFET's characteristic curve is sometimes referred to as the ohmic region."
Equating saturation portion of the FET characteristic curve with ohmic region would be confusing, if not inaccurate, since most textbooks actually refer to the region where the drain current nearly independent of the drain source voltage (the horizontal portion of the curve) as saturated region and the ohmic region as non-saturation/linear/triode region. The opposite!
In saturation region, the drain current is nearly independent of the drain-source voltage (hence the notion of saturation) and the relationship of VDS > VGS - VTH holds true.
In linear or ohmic region, the drain current does depend on, and varies linearly with, the drain-source voltage and the relationship of VDS < VGS - VTH is true.
I realise that this naming convention is confusing and counter-intuitive, especially because when a FET switch is fully on (where the drain-source voltage is saturated w.r.t drain current) we call the FET switch in saturation, although it is actually operating in linear/non-saturation/triode/ohmic region.
Also, the fact that the naming conventions of equivalent regions in BJT characteristic curve is the opposite (ohmic -> saturated, saturated -> active) doesn't help either!