Version 4
SHEET 1 880 680
WIRE 96 -16 -16 -16
WIRE -16 16 -16 -16
WIRE 96 32 96 -16
WIRE -16 128 -16 96
WIRE -16 256 -16 208
WIRE 48 256 -16 256
WIRE 96 256 48 256
WIRE 240 256 176 256
WIRE 560 288 368 288
WIRE 560 304 560 288
WIRE -16 320 -16 256
WIRE 48 320 48 256
WIRE 240 336 240 256
WIRE 368 352 368 288
WIRE 304 368 272 368
WIRE 336 368 304 368
WIRE 432 384 400 384
WIRE 336 400 304 400
WIRE 560 400 560 384
WIRE 560 400 496 400
WIRE 496 416 496 400
WIRE 560 416 560 400
WIRE -16 448 -16 384
WIRE 48 448 48 384
WIRE 48 448 -16 448
WIRE 112 448 48 448
WIRE 240 448 240 400
WIRE 240 448 112 448
WIRE 304 448 304 400
WIRE 432 448 432 384
WIRE 432 448 304 448
WIRE 112 480 112 448
WIRE 368 512 368 416
WIRE 560 512 560 496
WIRE 560 512 368 512
FLAG 96 32 0
FLAG 48 256 zener
FLAG 304 368 vout
FLAG 112 480 0
FLAG 496 416 0
SYMBOL res -32 112 R0
SYMATTR InstName R1
SYMATTR Value 1k
SYMBOL res 192 240 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL zener 0 384 R180
WINDOW 0 47 65 Left 0
WINDOW 3 45 33 Left 0
SYMATTR InstName D1
SYMATTR Value BZX84C8V2L
SYMBOL voltage -16 112 R180
WINDOW 0 24 104 Left 0
WINDOW 3 24 16 Left 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL cap 32 320 R0
WINDOW 0 44 33 Left 0
WINDOW 3 45 60 Left 0
SYMATTR InstName C1
SYMATTR Value 82n
SYMBOL voltage 560 288 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value 12
SYMBOL voltage 560 400 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value 12
SYMBOL Robertugo\\opamp5 368 320 R0
SYMATTR InstName U3
SYMBOL Robertugo\\Pote 256 304 M0
SYMATTR InstName U1
SYMATTR Value Rt=10k
SYMATTR Value2 Set={cur}
TEXT 280 88 Left 0 !.op
TEXT 280 64 Left 0 !.step param cur 0 1 .2