Version 4
SHEET 1 1260 864
WIRE -48 64 -64 64
WIRE 48 64 32 64
WIRE 80 64 48 64
WIRE 208 64 160 64
WIRE 352 64 208 64
WIRE -64 80 -64 64
WIRE 352 80 352 64
WIRE 208 96 208 64
WIRE 48 112 48 64
WIRE 128 112 48 112
WIRE 176 112 128 112
WIRE -384 128 -432 128
WIRE 272 128 240 128
WIRE 288 128 272 128
WIRE -256 144 -288 144
WIRE -32 144 -64 144
WIRE 0 144 -32 144
WIRE 176 144 0 144
WIRE 0 160 0 144
WIRE -288 176 -288 144
WIRE 208 176 208 160
WIRE 352 176 352 160
WIRE 128 192 128 112
WIRE -384 224 -384 208
WIRE -384 224 -432 224
WIRE -384 240 -384 224
WIRE 0 240 0 224
WIRE -288 304 -288 256
WIRE -144 304 -288 304
WIRE -96 304 -144 304
WIRE -64 304 -96 304
WIRE 128 304 128 256
WIRE 128 304 16 304
WIRE 288 304 288 128
WIRE 288 304 128 304
WIRE -384 320 -432 320
WIRE -144 320 -144 304
WIRE -144 400 -144 384
FLAG 0 240 0
FLAG -32 144 R1C1
FLAG 272 128 U1O
FLAG -144 400 0
FLAG -96 304 R3C3
FLAG 352 176 0
FLAG 352 64 5V
FLAG -64 80 0
FLAG 208 176 0
SYMBOL cap -16 160 R0
SYMATTR InstName C1
SYMATTR Value 1µ
SYMBOL res -160 160 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 0 56 VBottom 0
SYMATTR InstName R1
SYMATTR Value 1e3
SYMBOL Opamps\\1pole 208 128 R0
SYMATTR InstName U1
SYMBOL res 64 48 M90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R2
SYMATTR Value 500
SYMBOL cap 112 192 R0
SYMATTR InstName C2
SYMATTR Value 1µ
SYMBOL res -80 320 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 0 56 VBottom 0
SYMATTR InstName R3
SYMATTR Value 1e3
SYMBOL cap -160 320 R0
SYMATTR InstName C3
SYMATTR Value 10n
SYMBOL res -64 48 M90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R4
SYMATTR Value 500
SYMBOL Voltage 352 64 R0
WINDOW 123 34 79 Left 0
WINDOW 39 0 0 Left 0
WINDOW 3 35 76 Left 0
SYMATTR Value 5V
SYMATTR InstName V3
SYMBOL Digital\\74hc04 -208 80 R0
SYMATTR InstName U2
SYMATTR Value 74AC04
SYMBOL Ind -272 272 R180
WINDOW 0 128 99 Left 0
WINDOW 3 36 40 Left 0
SYMATTR InstName L1
SYMATTR Value ""
SYMBOL ind -400 112 R0
WINDOW 0 130 101 Left 0
SYMATTR InstName L2
SYMATTR Value ""
SYMBOL ind -400 224 R0
WINDOW 0 -22 56 Left 0
SYMATTR InstName L3
SYMATTR Value ""
TEXT -296 -64 Left 0 ;'74AC04 Limiter with Stabilized Threshold
TEXT -528 104 Left 0 ;Differential Input
TEXT -408 -40 Left 0 ;NOTE: This is the schematic illustration for the web page. It won't run as shown.