Difference between overdrive voltage and pinch-off voltage

[Mark_]

overdrive voltage Vov = VGS - VT
pinch-off voltage VDSAT is also VGS - VT
are they the same thing or I am making some mistake on the concept?
Thx in advance

 

[Harald Kapp]

VGS-VT expresses the voltage difference between gate voltage and threshold voltage.
When VGS-VT is greater than 0V, the gate is driven to more than the required gate voltage to turn on, it is overdriven. See Wikipedia.
Pinch off voltage is the drain voltage where saturation starts, that is where VDS=VGS-VT, see Wikipedia.

The difference is that VOV is measured between gate and source, VDS between drain and source.

 

[Mark_]

VGS-VT expresses the voltage difference between gate voltage and threshold voltage.
When VGS-VT is greater than 0V, the gate is driven to more than the required gate voltage to turn on, it is overdriven. See Wikipedia.
Pinch off voltage is the drain voltage where saturation starts, that is where VDS=VGS-VT, see Wikipedia.

The difference is that VOV is measured between gate and source, VDS between drain and source.

Thanks a lot!