Version 4
SHEET 1 880 680
WIRE 96 208 96 176
WIRE 96 304 96 288
WIRE 96 320 96 304
WIRE 208 176 96 176
WIRE 240 128 240 112
WIRE 240 144 240 128
WIRE 304 128 240 128
WIRE 320 32 240 32
WIRE 320 176 272 176
WIRE 320 304 96 304
WIRE 320 304 320 176
WIRE 352 0 352 -16
WIRE 432 -16 352 -16
WIRE 432 32 384 32
WIRE 432 32 432 -16
WIRE 432 128 384 128
WIRE 432 128 432 32
WIRE 432 192 432 128
WIRE 432 304 320 304
WIRE 432 304 432 272
FLAG 96 320 0
SYMBOL voltage 96 192 R0
WINDOW 3 -7 59 Left 0
SYMATTR Value 3
SYMATTR InstName Vctrl
SYMBOL res 400 112 R90
WINDOW 0 16 118 VBottom 0
WINDOW 3 -12 2 VTop 0
SYMATTR InstName Rc
SYMATTR Value 1k
SYMBOL voltage 432 176 R0
WINDOW 3 -6 60 Left 0
SYMATTR Value 3
SYMATTR InstName V2206
SYMBOL Robertugo\\Pote 176 160 M90
WINDOW 0 0 100 VRight 0
WINDOW 3 -21 -71 VRight 0
WINDOW 123 1 -24 VCenter 0
SYMATTR InstName Ugrueso
SYMATTR Value Rt=500
SYMATTR Value2 Set=10m
SYMBOL res 224 16 R0
WINDOW 0 -37 35 Left 0
WINDOW 3 -37 69 Left 0
SYMATTR InstName R1
SYMATTR Value 39k
SYMBOL Robertugo\\Pote 288 16 M90
WINDOW 0 -14 75 VRight 0
WINDOW 3 -21 -71 VRight 0
WINDOW 123 1 -24 VCenter 0
SYMATTR InstName Ufino
SYMATTR Value Rt=10k
SYMATTR Value2 Set={val}
TEXT 134 330 Left 0 !.tran 1m
TEXT 256 328 Left 0 !.step param val 0 1 .1