Version 4
SHEET 1 880 680
WIRE 272 16 224 16
WIRE 400 16 352 16
WIRE 448 16 400 16
WIRE 576 16 528 16
WIRE 480 128 480 112
WIRE 400 144 400 16
WIRE 448 144 400 144
WIRE 576 160 576 16
WIRE 576 160 512 160
WIRE 608 160 576 160
WIRE 48 176 -64 176
WIRE 176 176 128 176
WIRE 240 176 176 176
WIRE 352 176 320 176
WIRE 448 176 352 176
WIRE -64 208 -64 176
WIRE 480 208 480 192
WIRE 176 224 176 176
WIRE 352 224 352 176
WIRE -64 320 -64 288
WIRE 176 320 176 288
WIRE 352 320 352 288
WIRE 480 320 480 304
WIRE 608 320 608 304
WIRE 480 416 480 400
WIRE 608 416 608 400
FLAG -64 320 0
FLAG 224 16 0
FLAG 480 112 V+
FLAG 480 208 V-
FLAG 176 320 0
FLAG 352 320 0
FLAG 608 160 out
IOPIN 608 160 Out
FLAG 480 416 0
FLAG 608 416 0
FLAG 480 304 V-
FLAG 608 304 V+
FLAG -64 176 in
SYMBOL Misc\\EuropeanResistor 144 160 R90
WINDOW 0 5 56 VBottom 2
WINDOW 3 27 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 33k
SYMBOL Misc\\EuropeanResistor 336 160 R90
WINDOW 0 5 56 VBottom 2
WINDOW 3 27 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 33k
SYMBOL Opamps\\UniversalOpamp2 480 160 R0
SYMATTR InstName U1
SYMBOL voltage -64 192 R0
WINDOW 3 -17 171 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR Value PULSE(0 3.3 0 10n 10n 1m 10m)
SYMATTR InstName V1
SYMBOL cap 160 224 R0
SYMATTR InstName C1
SYMATTR Value 100µ
SYMBOL cap 336 224 R0
SYMATTR InstName C2
SYMATTR Value 100µ
SYMBOL voltage 480 304 R0
SYMATTR InstName V2
SYMATTR Value -15
SYMBOL voltage 608 304 R0
SYMATTR InstName V3
SYMATTR Value 15
SYMBOL Misc\\EuropeanResistor 368 0 R90
WINDOW 0 5 56 VBottom 2
WINDOW 3 27 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 10k
SYMBOL Misc\\EuropeanResistor 544 0 R90
WINDOW 0 5 56 VBottom 2
WINDOW 3 27 56 VTop 2
SYMATTR InstName R4
SYMATTR Value 20k
TEXT -80 472 Left 2 !.tran 50
TEXT -80 512 Left 2 !.options plotwinsize=0
TEXT 280 -64 Left 2 ;v = (1+R4/R3) = 3