Version 4
SHEET 1 880 680
WIRE 416 112 192 112
WIRE 336 144 256 144
WIRE 256 240 256 144
WIRE 336 240 336 224
WIRE 112 256 112 112
WIRE 224 256 112 256
WIRE 416 272 416 112
WIRE 416 272 288 272
WIRE 224 288 112 288
WIRE 112 320 112 288
WIRE 416 336 336 336
WIRE 336 352 336 336
WIRE 416 352 416 336
WIRE 32 400 32 256
WIRE 112 400 32 400
WIRE 112 416 112 400
WIRE 256 432 256 304
WIRE 336 432 256 432
FLAG 112 416 0
FLAG 336 240 0
FLAG 416 352 0
SYMBOL res 128 240 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 10k
SYMBOL res 208 96 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 20k
SYMBOL voltage 112 304 R0
WINDOW 123 28 96 Left 2
WINDOW 39 0 0 Left 0
SYMATTR Value2 AC 1 0
SYMATTR InstName V1
SYMATTR Value ""
SYMBOL OpAmps\\OP747 256 208 R0
SYMATTR InstName U1
SYMBOL voltage 336 128 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value 15
SYMBOL voltage 336 336 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value 15
TEXT 24 472 Left 2 !.ac lin 100 999 1001