Version 4
SHEET 1 880 680
WIRE 240 96 112 96
WIRE 240 144 240 96
WIRE -224 160 -368 160
WIRE -128 160 -224 160
WIRE -16 160 -128 160
WIRE 208 160 -16 160
WIRE 368 176 272 176
WIRE 448 176 368 176
WIRE 592 176 528 176
WIRE 208 192 144 192
WIRE 368 192 368 176
WIRE -368 256 -368 160
WIRE -16 256 -16 160
WIRE 592 256 592 176
WIRE -224 304 -224 160
WIRE -128 304 -128 160
WIRE 144 304 144 192
WIRE 368 304 368 272
WIRE 368 304 144 304
WIRE -368 336 -368 320
WIRE 112 336 112 96
WIRE 240 336 240 208
WIRE 368 336 368 304
WIRE -368 496 -368 416
WIRE -224 496 -224 368
WIRE -224 496 -368 496
WIRE -128 496 -128 368
WIRE -128 496 -224 496
WIRE -16 496 -16 336
WIRE -16 496 -128 496
WIRE 112 496 112 416
WIRE 112 496 -16 496
WIRE 176 496 112 496
WIRE 240 496 240 416
WIRE 240 496 176 496
WIRE 368 496 368 416
WIRE 368 496 240 496
WIRE 592 496 592 320
WIRE 592 496 368 496
WIRE 176 512 176 496
FLAG 176 512 0
SYMBOL Opamps\\LT1128 240 112 R0
SYMATTR InstName U1
SYMBOL res 352 176 R0
SYMATTR InstName R1
SYMATTR Value 500k
SYMBOL res 352 320 R0
SYMATTR InstName R2
SYMATTR Value 100k
SYMBOL voltage 240 320 R0
WINDOW 0 33 36 Left 2
WINDOW 3 36 62 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value -15
SYMBOL voltage 112 320 R0
WINDOW 0 34 41 Left 2
WINDOW 3 36 65 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value 15
SYMBOL voltage -368 320 R0
WINDOW 0 41 45 Left 2
WINDOW 3 40 98 Left 2
WINDOW 123 40 126 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V3
SYMATTR Value ""
SYMATTR Value2 AC 5
SYMBOL cap -384 256 R0
SYMATTR InstName C1
SYMATTR Value 1n
SYMBOL res -32 240 R0
SYMATTR InstName R3
SYMATTR Value 10k
SYMBOL res 544 160 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R4
SYMATTR Value 51
SYMBOL cap 576 256 R0
SYMATTR InstName C2
SYMATTR Value 100n
SYMBOL diode -240 304 R0
WINDOW 3 18 65 Left 2
SYMATTR Value 1N4148
SYMATTR InstName D1
SYMBOL diode -112 368 R180
WINDOW 0 -22 64 Left 2
WINDOW 3 -75 -3 Left 2
SYMATTR InstName D2
SYMATTR Value 1N4148
TEXT 472 536 Left 2 !.ac dec 100 1 300k
TEXT -416 320 Left 1 ;Piezo
TEXT -264 144 Left 1 ;Overvoltage-Protection
TEXT -8 336 Left 1 ;Highpass
TEXT 136 416 Left 1 ;OP Supply
TEXT 248 128 Left 1 ;Non-Inverting Amplifier
TEXT 512 224 Left 1 ;Lowpass
TEXT -48 40 Left 4 ;Piezo Amplifier/Filter