On 7/13/2013 2:11 PM, Phil Hobbs wrote:
And here's one with a BF862 as the current source, with and without a floating bias voltage.
Cheers
Phil Hobbs
Version 4 SHEET 1 880 680 WIRE -224 32 -432 32 WIRE -80 32 -224 32 WIRE 208 32 -80 32 WIRE 80 96 32 96 WIRE 208 96 208 32 WIRE 208 96 144 96 WIRE 256 96 208 96 WIRE 384 96 320 96 WIRE 176 128 96 128 WIRE 176 144 176 128 WIRE -432 160 -432 32 WIRE -224 160 -224 32 WIRE -80 160 -80 32 WIRE 32 192 32 96 WIRE 96 192 96 128 WIRE 96 192 32 192 WIRE 144 192 96 192 WIRE 256 192 240 192 WIRE 384 192 384 96 WIRE 384 192 336 192 WIRE 32 320 32 192 WIRE 80 320 32 320 WIRE 208 320 144 320 WIRE 256 320 208 320 WIRE 384 320 384 192 WIRE 384 320 320 320 WIRE -432 368 -432 240 WIRE -224 368 -224 224 WIRE -224 368 -432 368 WIRE -80 368 -80 240 WIRE -80 368 -224 368 WIRE 208 368 208 320 WIRE 208 368 -80 368 WIRE -80 400 -80 368 FLAG -80 400 0 SYMBOL diode 256 112 R270 WINDOW 0 44 17 VTop 2 WINDOW 3 71 74 VBottom 2 SYMATTR InstName D2 SYMATTR Value {diode} SYMBOL ind -64 256 R180 WINDOW 0 49 82 Left 2 WINDOW 3 47 41 Left 2 SYMATTR InstName L1 SYMATTR Value 1m SYMBOL cap -240 160 R0 WINDOW 0 -54 14 Left 2 WINDOW 3 -57 54 Left 2 SYMATTR InstName C1 SYMATTR Value 1µ SYMBOL current -432 240 R180 WINDOW 0 21 -17 Left 2 WINDOW 3 -174 -162 Left 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName I2 SYMATTR Value PULSE(0 1 0 0 0 10u) SYMBOL diode 256 336 R270 WINDOW 0 42 10 VTop 2 WINDOW 3 70 72 VBottom 2 SYMATTR InstName D1 SYMATTR Value {diode} SYMBOL diode 80 336 R270 WINDOW 0 44 17 VTop 2 WINDOW 3 74 79 VBottom 2 SYMATTR InstName D3 SYMATTR Value {diode} SYMBOL diode 80 112 R270 WINDOW 0 44 17 VTop 2 WINDOW 3 70 83 VBottom 2 SYMATTR InstName D4 SYMATTR Value {diode} SYMBOL voltage 240 192 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 -32 56 VBottom 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V1 SYMATTR Value {Vbias} SYMBOL njf 240 144 R90 WINDOW 0 20 92 VRight 2 WINDOW 3 74 70 VRight 2 SYMATTR InstName J1 SYMATTR Value BF862J TEXT 88 400 Left 2 !.model Di D(Vfwd=0) TEXT -216 -32 Left 2 !.tran 10m TEXT 112 -32 Left 2 ;Frictional equivalent resistor, hacked a bit more TEXT 240 0 Left 2 ;JL/PH July 12, 2013 TEXT 432 112 Left 2 !.model 1 AKO: BAT54\n.model 2 AKO: Di TEXT 408 192 Left 2 !.step param diode list 1 2\n.step param Vbias list
0 0.5 TEXT -480 456 Left 2 !.model BF862J NJF(Beta=47.800E-3 Betatce=-.5 Rd=.8 Rs=7.5000 Lambda=37.300E-3 Vto=-.57093