Version 4
SHEET 1 1208 724
WIRE -112 384 -112 336
WIRE 80 496 80 672
WIRE 80 672 -112 672
WIRE -112 528 -112 480
WIRE -112 608 -112 672
WIRE -112 704 -112 672
WIRE -112 256 -112 208
WIRE 32 480 -112 480
WIRE -112 208 80 208
WIRE 80 208 80 400
FLAG -112 704 0
FLAG -112 384 0
FLAG -112 208 Vd
FLAG -112 480 Vg
SYMBOL voltage -112 512 R0
WINDOW 123 24 132 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName Vgs
SYMATTR Value {VGS}
SYMBOL voltage -112 240 R0
WINDOW 123 24 132 Left 0
WINDOW 39 0 0 Left 0
SYMATTR Value2 AC 1
SYMATTR InstName Vds
SYMATTR Value {VDS}
SYMBOL nmos 32 400 R0
SYMATTR InstName M1
SYMATTR Value BSS83
TEXT -112 -224 Left 0 !.step param VDS 0 10 0.01
TEXT -112 -184 Left 0 !.OP
TEXT -112 -144 Left 0 !.TF I(Vds) Vds
TEXT -104 -56 Left 0 ;.AC LIST 1K
TEXT 56 -56 Left 0 ;Alternative method instead of .TF :  .AC LIST 1\nPlot Id(M1) or I(Vds) to get Gds at 1Hz.
TEXT 56 -144 Left 0 ;Calculates output conductance "Gds" at DC.\nChoose "-Transfer_function" in the plot window.
TEXT 56 -184 Left 0 ;Allows plotting of Id(M1) versus Vds if the .TF command is disabled.
TEXT -120 -416 Left 0 ;Output Conductance "Gds" Versus Drain Source Voltage\n \nPlot  -Transfer_function  to get Gds versus Vds.  \nWatch the - sign to get the correct sign of Gds.\nPlot  -1/Transfer_function  to get the output impedance.
TEXT -104 40 Left 0 ;Gerneral hint for plots:\nMake the plot window active. \n"PlotSettings->Add Trace" and select an item\nor "right mouse button  ->Add Trace" and select an item.
TEXT -112 -264 Left 0 !.param VGS=3.3
TEXT 256 280 Left 0 !* Model from Philips Semiconductor\n.MODEL BSS83 NMOS\n+ LEVEL=3\n+ W=1E-3\n+ L=1E-6\n+ VTO=2\n+ VMAX=1E6\n+ RS=3\n+ RD=3\n+ CJ=0.001396\n+ MJ=0.3936\n+ THETA=1E-6\n+ ETA=0.009307\n+ KAPPA=2.226