* SPICE netlist
Q1 N006 Vref N010 0 TR1
Q2 N009 Vf N010 0 TR1
Q3 N007 N009 N001 0 2N2222
Q5 N010 N018 N026 0 BC547B
Q6 N018 N018 N025 0 BC547B
R1 Vref N018 200
R2 Vreg N003 0.1k
R3 Vreg N002 0.1k
RL Vo 0 R = 100*(1-time)
Q7 N001 N007 Vreg 0 tip42c
Q8 N009 N006 N003 0 BC557B
Q9 N006 N006 N002 0 BC557B
V1 Vreg 0 6.35
V2 Vref 0 1.2
R7 N001 N004 2.2k
R8 Vo N008 2.2k
R9 N004 0 22k
R10 N008 Vs 22k
R11 N020 Vref 7.5k
R12 0 N020 1k
R13 N015 N021 1k
R14 Vref-c N022 1k
R15 N015 N016 960
R16 N014 Vf 4.3k
R17 0 N014 4.3k
R20 N013 Vref-c 2.2k
R22 N012 N011 17k
R23 N017 0 10
R24 N022 0 1k
R21 N012 N013 82k
R200 Vs N005 2.2k
R19 0 N005 82k
R4 N001 Vo 0.1
Q4 N009 N011 N017 0 2N2222
R18 N025 0 10
R25 N026 0 10
XU6 N015 N022 5v 0 Vref-c LM324 ;pnba In+)In-)V+)V-)OUT
XU2 N004 N008 5v 0 Vs TLV2371 ;pnba In+)In-)V+)V-)OUT
XU1 N005 N013 5v 0 N012 LM324 ;pnba In+)In-)V+)V-)OUT
XU3 N014 N016 5v 0 N016 LM324 ;pnba In+)In-)V+)V-)OUT
XU4 N020 N021 5v 0 N021 LM324 ;pnba In+)In-)V+)V-)OUT
V3 5v 0 5
R5 Vo Vf 3.3k
R26 Vf N019 1.2k
M1 N019 N023 0 0 BSZ100N03LS
R28 N024 N023 1k
V4 N024 0 0
R27 N019 0 1.2k
;step param RE 1k 1.5k 100
;param RL=6
.tran 0.999999
.include librerias/bd140.lib
.include librerias/complex_discretes.lib
.inc opamp.sub
.meas DC Vo1rl FIND V(Vo) AT=6.15
.meas DC Vo2rl FIND V(Vo) AT=6.35
.meas DC RegLin PARAM ((Vo2rl-Vo1rl)/1.85)
.meas OP Vo1rc FIND V(Vo) AT 100
.meas OP Vo2rc FIND V(Vo) AT 5
.meas OP Io1rc FIND I(RL) AT 100
.meas OP Io2rc FIND I(RL) AT 5

* LTspice schematic (.asc)
Version 4
SHEET 1 4272 1408
WIRE -1448 -704 -1560 -704
WIRE -1112 -704 -1448 -704
WIRE -904 -704 -1112 -704
WIRE -712 -704 -904 -704
WIRE -472 -704 -616 -704
WIRE 680 -704 -472 -704
WIRE 728 -704 680 -704
WIRE 856 -704 808 -704
WIRE 1544 -704 856 -704
WIRE 1592 -704 1544 -704
WIRE 2136 -704 1592 -704
WIRE -1560 -672 -1560 -704
WIRE -1112 -656 -1112 -704
WIRE -904 -640 -904 -704
WIRE 680 -640 680 -704
WIRE 856 -640 856 -704
WIRE -1560 -560 -1560 -592
WIRE -1112 -544 -1112 -576
WIRE -904 -544 -904 -560
WIRE 680 -528 680 -560
WIRE 680 -528 584 -528
WIRE 8 -512 -152 -512
WIRE 56 -512 8 -512
WIRE 184 -512 136 -512
WIRE 472 -512 184 -512
WIRE 520 -512 472 -512
WIRE -1016 -496 -1048 -496
WIRE -968 -496 -1016 -496
WIRE -664 -496 -664 -640
WIRE -632 -496 -664 -496
WIRE -472 -496 -472 -704
WIRE -472 -496 -536 -496
WIRE 616 -496 584 -496
WIRE 856 -496 856 -560
WIRE 856 -496 616 -496
WIRE 8 -480 8 -512
WIRE 680 -432 680 -528
WIRE -1112 -416 -1112 -448
WIRE -1016 -416 -1016 -496
WIRE -1016 -416 -1112 -416
WIRE -904 -416 -904 -448
WIRE -648 -416 -904 -416
WIRE -584 -416 -584 -432
WIRE -584 -416 -648 -416
WIRE 1544 -416 1544 -704
WIRE 472 -384 472 -512
WIRE 504 -384 472 -384
WIRE 616 -384 616 -496
WIRE 616 -384 584 -384
WIRE 8 -368 8 -400
WIRE 680 -304 680 -352
WIRE -1112 -256 -1112 -416
WIRE -904 -256 -904 -416
WIRE -1480 -208 -1592 -208
WIRE -1400 -208 -1480 -208
WIRE -1176 -208 -1400 -208
WIRE -808 -208 -840 -208
WIRE -648 -176 -648 -416
WIRE -152 -144 -152 -512
WIRE -152 -144 -296 -144
WIRE -1592 -128 -1592 -208
WIRE -1112 -128 -1112 -160
WIRE -1000 -128 -1112 -128
WIRE -904 -128 -904 -160
WIRE -904 -128 -1000 -128
WIRE -536 -128 -584 -128
WIRE -376 -128 -456 -128
WIRE -360 -128 -376 -128
WIRE -152 -112 -296 -112
WIRE 2136 -96 2136 -704
WIRE 888 -80 728 -80
WIRE 968 -80 888 -80
WIRE 1240 -80 1048 -80
WIRE 1368 -80 1240 -80
WIRE 1544 -80 1544 -336
WIRE 1544 -80 1368 -80
WIRE 536 -64 440 -64
WIRE 632 -64 616 -64
WIRE 664 -64 632 -64
WIRE 776 -48 728 -48
WIRE -1592 -16 -1592 -48
WIRE 696 -16 696 -32
WIRE 888 -16 888 -80
WIRE 1544 -16 1544 -80
WIRE 632 16 632 -64
WIRE 776 16 776 -48
WIRE 776 16 632 16
WIRE -1400 32 -1400 -208
WIRE -376 32 -376 -128
WIRE -328 32 -376 32
WIRE -152 32 -152 -112
WIRE -152 32 -248 32
WIRE 888 112 888 64
WIRE -648 160 -648 -80
WIRE -1400 192 -1400 112
WIRE -1288 192 -1400 192
WIRE 1544 224 1544 64
WIRE 1544 224 1416 224
WIRE -1400 240 -1400 192
WIRE -1000 240 -1000 -128
WIRE 856 240 712 240
WIRE 920 240 856 240
WIRE 1048 240 1000 240
WIRE 440 256 440 -64
WIRE 440 256 360 256
WIRE 472 256 440 256
WIRE 584 256 552 256
WIRE 648 256 584 256
WIRE -152 272 -152 32
WIRE -56 272 -152 272
WIRE 200 272 24 272
WIRE 296 272 200 272
WIRE 760 272 712 272
WIRE 1544 272 1544 224
WIRE -1288 288 -1288 192
WIRE -1288 288 -1336 288
WIRE -1064 288 -1288 288
WIRE 424 288 360 288
WIRE 1704 352 1592 352
WIRE 1880 352 1784 352
WIRE -2136 368 -2136 288
WIRE 584 384 584 256
WIRE 760 384 760 272
WIRE 760 384 584 384
WIRE -1400 400 -1400 336
WIRE -1000 400 -1000 336
WIRE 200 400 200 272
WIRE 264 400 200 400
WIRE 392 400 344 400
WIRE 424 400 424 288
WIRE 424 400 392 400
WIRE 856 416 856 240
WIRE 1416 432 1416 224
WIRE 1880 432 1880 352
WIRE 392 448 392 400
WIRE -2136 480 -2136 448
WIRE -808 544 -808 -208
WIRE 1240 544 1240 -80
WIRE 1240 544 -808 544
WIRE -1400 640 -1400 480
WIRE -1000 640 -1000 480
WIRE -1000 640 -1400 640
WIRE -648 640 -648 240
WIRE -648 640 -1000 640
WIRE -264 640 -648 640
WIRE 392 640 392 528
WIRE 392 640 -264 640
WIRE 856 640 856 496
WIRE 856 640 392 640
WIRE 1416 640 1416 512
WIRE 1416 640 856 640
WIRE 1544 640 1544 368
WIRE 1544 640 1416 640
WIRE 1880 640 1880 512
WIRE 1880 640 1544 640
WIRE 2136 640 2136 -16
WIRE 2136 640 1880 640
WIRE -264 704 -264 640
FLAG -264 704 0
FLAG -1560 -560 0
FLAG -1592 -16 0
FLAG -1448 -704 Vreg
FLAG -1480 -208 Vref
FLAG 184 -512 Vs
FLAG 888 112 0
FLAG 200 272 Vref-c
FLAG 8 -368 0
FLAG 1048 240 Vref
FLAG 1368 -80 Vf
FLAG 680 -304 0
FLAG -264 640 0V
FLAG 552 -544 0V
FLAG -328 -160 0V
FLAG 696 -96 0V
FLAG 680 224 0V
FLAG 328 240 0V
FLAG -2136 480 0
FLAG -2136 288 5v
FLAG 696 -16 5v
FLAG 552 -480 5v
FLAG 680 288 5v
FLAG 328 304 5v
FLAG -328 -96 5v
FLAG 1592 -704 Vo
DATAFLAG 16 160 ""
DATAFLAG 336 -16 ""
DATAFLAG 128 32 ""
DATAFLAG 3296 -336 ""
DATAFLAG 1824 -336 ""
DATAFLAG 1632 -144 ""
DATAFLAG 1088 160 ""
DATAFLAG 1088 304 ""
DATAFLAG 816 240 ""
DATAFLAG 2512 288 ""
DATAFLAG 2096 688 ""
DATAFLAG 1840 624 ""
DATAFLAG 1360 640 ""
SYMBOL npn -1176 -256 R0
SYMATTR InstName Q1
SYMATTR Value TR1
SYMBOL npn -840 -256 M0
SYMATTR InstName Q2
SYMATTR Value TR1
SYMBOL npn -632 -432 R270
SYMATTR InstName Q3
SYMATTR Value 2N2222
SYMBOL npn -1064 240 R0
SYMATTR InstName Q5
SYMATTR Value BC547B
SYMBOL npn -1336 240 M0
SYMATTR InstName Q6
SYMATTR Value BC547B
SYMBOL res -1416 16 R0
SYMATTR InstName R1
SYMATTR Value 200
SYMBOL res -920 -656 R0
SYMATTR InstName R2
SYMATTR Value 0.1k
SYMBOL res -1128 -672 R0
SYMATTR InstName R3
SYMATTR Value 0.1k
SYMBOL res 2120 -112 R0
SYMATTR InstName RL
SYMATTR Value R = 100*(1-time)
SYMBOL pnp -616 -640 M270
SYMATTR InstName Q7
SYMATTR Value tip42c
SYMBOL pnp -968 -448 M180
SYMATTR InstName Q8
SYMATTR Value BC557B
SYMBOL pnp -1048 -448 R180
SYMATTR InstName Q9
SYMATTR Value BC557B
SYMBOL voltage -1560 -688 R0
SYMATTR InstName V1
SYMATTR Value 6.35
SYMBOL voltage -1592 -144 R0
SYMATTR InstName V2
SYMATTR Value 1.2
SYMBOL res 664 -656 R0
SYMATTR InstName R7
SYMATTR Value 2.2k
SYMBOL res 840 -656 R0
SYMATTR InstName R8
SYMATTR Value 2.2k
SYMBOL res 664 -448 R0
SYMATTR InstName R9
SYMATTR Value 22k
SYMBOL res 600 -400 R90
SYMATTR InstName R10
SYMATTR Value 22k
SYMBOL res 904 224 M90
SYMATTR InstName R11
SYMATTR Value 7.5k
SYMBOL res 840 512 M180
SYMATTR InstName R12
SYMATTR Value 1k
SYMBOL res 456 240 M90
SYMATTR InstName R13
SYMATTR Value 1k
SYMBOL res 248 384 M90
SYMATTR InstName R14
SYMATTR Value 1k
SYMBOL res 520 -80 M90
SYMATTR InstName R15
SYMATTR Value 960
SYMBOL res 952 -96 M90
SYMATTR InstName R16
SYMATTR Value 4.3k
SYMBOL res 872 80 M180
SYMATTR InstName R17
SYMATTR Value 4.3k
SYMBOL res -72 288 R270
SYMATTR InstName R20
SYMATTR Value 2.2k
SYMBOL res -440 -144 R90
SYMATTR InstName R22
SYMATTR Value 17k
SYMBOL res -664 144 R0
SYMATTR InstName R23
SYMATTR Value 10
SYMBOL res 408 432 M0
SYMATTR InstName R24
SYMATTR Value 1k
SYMBOL res -344 48 R270
SYMATTR InstName R21
SYMATTR Value 82k
SYMBOL res 152 -528 R90
SYMATTR InstName R200
SYMATTR Value 2.2k
SYMBOL res 24 -384 R180
SYMATTR InstName R19
SYMATTR Value 82k
SYMBOL res 712 -688 R270
SYMATTR InstName R4
SYMATTR Value 0.1
SYMBOL npn -584 -176 M0
SYMATTR InstName Q4
SYMATTR Value 2N2222
SYMBOL res -1416 384 R0
SYMATTR InstName R18
SYMATTR Value 10
SYMBOL res -1016 384 R0
SYMATTR InstName R25
SYMATTR Value 10
SYMBOL OpAmps\\opamp2 328 336 R180
SYMATTR Value LM324
SYMATTR InstName U6
SYMBOL OpAmps\\opamp2 552 -448 R180
SYMATTR Value TLV2371
SYMATTR InstName U2
SYMBOL OpAmps\\opamp2 -328 -64 R180
SYMATTR Value LM324
SYMATTR InstName U1
SYMBOL OpAmps\\opamp2 696 0 R180
SYMATTR Value LM324
SYMATTR InstName U3
SYMBOL OpAmps\\opamp2 680 320 R180
SYMATTR Value LM324
SYMATTR InstName U4
SYMBOL voltage -2136 352 R0
SYMATTR InstName V3
SYMATTR Value 5
SYMBOL res 1528 -432 R0
SYMATTR InstName R5
SYMATTR Value 3.3k
SYMBOL res 1528 -32 R0
SYMATTR InstName R26
SYMATTR Value 1.2k
SYMBOL nmos 1592 272 M0
SYMATTR InstName M1
SYMATTR Value BSZ100N03LS
SYMBOL res 1800 336 R90
SYMATTR InstName R28
SYMATTR Value 1k
SYMBOL voltage 1880 416 R0
SYMATTR InstName V4
SYMATTR Value 0
SYMBOL res 1400 416 R0
SYMATTR InstName R27
SYMATTR Value 1.2k