Version 4
SHEET 1 1188 680
WIRE 16 48 16 32
WIRE 224 112 208 112
WIRE 320 112 304 112
WIRE 736 112 576 112
WIRE 768 112 736 112
WIRE 864 112 848 112
WIRE 736 128 736 112
WIRE -96 144 -288 144
WIRE 16 144 16 128
WIRE 16 144 -16 144
WIRE -288 160 -288 144
WIRE 16 176 16 144
WIRE 320 176 16 176
WIRE 592 176 576 176
WIRE 688 176 672 176
WIRE 320 240 16 240
WIRE 736 240 736 208
WIRE 736 240 576 240
WIRE 784 240 736 240
WIRE -288 272 -288 240
WIRE -96 272 -288 272
WIRE 16 272 16 240
WIRE 16 272 -16 272
WIRE 16 288 16 272
WIRE 256 304 144 304
WIRE 320 304 256 304
WIRE 592 304 576 304
WIRE 144 320 144 304
WIRE 256 320 256 304
WIRE 16 384 16 368
WIRE 144 416 144 400
WIRE 256 416 256 400
WIRE 448 416 256 416
WIRE 592 416 592 304
WIRE 592 416 528 416
WIRE 256 432 256 416
WIRE 256 528 256 512
FLAG 688 176 0
FLAG 144 416 0
FLAG 208 112 0
FLAG 864 112 0
FLAG 256 528 0
FLAG 16 32 0
FLAG 16 384 0
FLAG 784 240 OUT
SYMBOL voltage 576 176 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 -32 56 VBottom 2
SYMATTR InstName V1
SYMATTR Value 15
SYMBOL voltage 144 304 R0
SYMATTR InstName V2
SYMATTR Value -15
SYMBOL res 320 96 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 270
SYMBOL opamps\\LT1228 448 208 R0
SYMATTR InstName U1
SYMBOL res 720 112 R0
SYMATTR InstName R3
SYMATTR Value 470
SYMBOL res 864 96 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R4
SYMATTR Value 10
SYMBOL res 240 304 R0
SYMATTR InstName R5
SYMATTR Value 1.24K
SYMBOL res 240 416 R0
SYMATTR InstName R6
SYMATTR Value 6.19K
SYMBOL res 432 400 M90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R7
SYMATTR Value {R}
SYMBOL res 0 144 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R1
SYMATTR Value 100
SYMBOL res 0 272 R0
SYMATTR InstName R8
SYMATTR Value 100
SYMBOL res 0 128 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R9
SYMATTR Value 10K
SYMBOL res 0 256 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R10
SYMATTR Value 10K
SYMBOL voltage -288 144 R0
WINDOW 123 24 138 Left 2
WINDOW 39 24 117 Left 2
SYMATTR InstName V3
SYMATTR Value SINE(0 .1 10K)
TEXT 640 448 Left 2 !.tran 3m\n.step param R list 10K 5K 2.5K 1.25K