Version 4
SHEET 1 880 680
WIRE -656 128 -800 128
WIRE -416 128 -592 128
WIRE -912 240 -960 240
WIRE -800 240 -800 128
WIRE -800 240 -832 240
WIRE -768 240 -800 240
WIRE -624 240 -688 240
WIRE -512 240 -624 240
WIRE -416 256 -416 128
WIRE -416 256 -448 256
WIRE -336 256 -416 256
WIRE -512 272 -544 272
WIRE -416 272 -416 256
WIRE -624 288 -624 240
WIRE -960 304 -960 240
WIRE -544 368 -544 272
WIRE -416 368 -416 352
WIRE -416 368 -544 368
WIRE -416 384 -416 368
WIRE -960 464 -960 384
WIRE -624 464 -624 352
WIRE -416 480 -416 464
FLAG -960 240 Uin
IOPIN -960 240 In
FLAG -336 256 Uout
IOPIN -336 256 Out
FLAG -416 480 0
FLAG -624 464 0
FLAG -960 464 0
SYMBOL res -432 256 R0
SYMATTR InstName R3
SYMATTR Value 5858
SYMBOL res -432 368 R0
SYMATTR InstName R4
SYMATTR Value 10k
SYMBOL res -816 224 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 14469
SYMBOL cap -640 352 M180
WINDOW 0 24 56 Left 2
WINDOW 3 24 8 Left 2
SYMATTR InstName C1
SYMATTR Value 2.2n
SYMBOL voltage -960 288 R0
WINDOW 123 48 104 Left 2
WINDOW 39 0 0 Left 2
WINDOW 0 -56 27 Left 2
WINDOW 3 44 69 Left 2
SYMATTR Value2 AC 1
SYMATTR InstName V2
SYMATTR Value SINE(0 1 5k)
SYMBOL Opamps\\opamp -480 320 M180
SYMATTR InstName U2
SYMATTR SpiceLine Aol=10000K
SYMATTR SpiceLine2 GBW=1000Meg
SYMBOL res -672 224 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 14469
SYMBOL cap -656 144 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName C2
SYMATTR Value 2.2n
TEXT -1008 -72 Left 2 !.lib opamp.sub
TEXT -1008 -104 Left 2 !.ac dec 1000 100 1meg
TEXT -552 -104 Left 2 ;Butterworth: a1=sqrt(2)\na = 3 -a1 = 3-sqrt(2) = 1.5858\nR3 = (a-1)*R4 = 5.858kOkm\nR1=R2  C1=C2\nfg = 1/(2*pi*R*C) \nfg = 5kHz