Version 4
SHEET 1 1136 680
WIRE 208 -64 176 -64
WIRE 304 -64 288 -64
WIRE 320 -64 304 -64
WIRE 416 -64 400 -64
WIRE 352 32 352 16
WIRE 304 48 304 -64
WIRE 320 48 304 48
WIRE 416 64 416 -64
WIRE 416 64 384 64
WIRE 656 64 416 64
WIRE 320 80 128 80
WIRE 656 96 656 64
WIRE 352 112 352 96
WIRE -224 160 -224 144
WIRE -112 160 -112 144
WIRE 608 160 592 160
WIRE 16 192 0 192
WIRE 128 192 128 80
WIRE 128 192 96 192
WIRE 208 192 176 192
WIRE 304 192 288 192
WIRE 320 192 304 192
WIRE 416 192 400 192
WIRE 496 192 480 192
WIRE 592 192 592 160
WIRE 592 192 576 192
WIRE 656 192 656 176
WIRE 720 192 656 192
WIRE 656 208 656 192
WIRE 592 224 592 192
WIRE 608 224 592 224
WIRE -224 256 -224 240
WIRE -112 256 -112 240
WIRE 352 288 352 272
WIRE 304 304 304 192
WIRE 320 304 304 304
WIRE 416 320 416 192
WIRE 416 320 384 320
WIRE 656 320 656 288
WIRE 656 320 416 320
WIRE 128 336 128 192
WIRE 320 336 128 336
WIRE 352 368 352 352
FLAG 352 16 +V
FLAG 352 112 -V
FLAG -112 256 0
FLAG -224 256 0
FLAG -224 144 +V
FLAG -112 144 -V
FLAG 0 192 0
FLAG 352 272 +V
FLAG 352 368 -V
FLAG 608 112 0
FLAG 608 272 0
FLAG 480 192 0
FLAG 720 192 OUT
FLAG 176 -64 0
FLAG 176 192 0
SYMBOL voltage 112 192 R90
WINDOW 0 -32 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName V1
SYMATTR Value ac 1
SYMBOL voltage -112 144 R0
SYMATTR InstName V2
SYMATTR Value -15
SYMBOL voltage -224 144 R0
SYMATTR InstName V3
SYMATTR Value +15
SYMBOL opamps\\UniversalOpamp2 352 320 R0
SYMATTR InstName U1
SYMATTR Value2 Avol=800K GBW=75Meg Slew=.25Meg
SYMATTR SpiceLine2 en=.85n enk=3 in=1p ink=50 Rin=500Meg
SYMBOL sw 656 192 M180
WINDOW 0 29 92 Left 0
WINDOW 3 18 22 Left 0
SYMATTR InstName S2
SYMBOL sw 656 304 M180
WINDOW 0 28 89 Left 0
WINDOW 3 18 22 Left 0
SYMATTR InstName S1
SYMBOL voltage 592 192 R90
WINDOW 0 -32 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName V4
SYMATTR Value {X}
SYMBOL res 416 -80 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R1
SYMATTR Value 10K
SYMBOL res 304 -80 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R2
SYMATTR Value 10
SYMBOL res 416 176 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R3
SYMATTR Value 10K
SYMBOL res 304 176 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R4
SYMATTR Value 10
SYMBOL opamps\\LT1028A 352 0 R0
SYMATTR InstName U2
TEXT -200 376 Left 0 !.model SW SW(Ron=1 Roff=1G Vt=0 Vh=0)
TEXT 496 384 Left 0 !.step param X list -1 1
TEXT 496 352 Left 0 !.noise V(out) V1 oct 20 .1 10Meg