Version 4
SHEET 1 880 680
WIRE 192 64 80 64
WIRE 320 64 192 64
WIRE 80 144 80 128
WIRE 80 144 -16 144
WIRE 192 176 192 128
WIRE 192 176 -16 176
WIRE 80 208 80 144
WIRE 192 208 192 176
WIRE 192 272 80 272
WIRE 320 272 192 272
FLAG -16 144 V+~
IOPIN -16 144 BiDir
FLAG -16 176 V-~
IOPIN -16 176 BiDir
FLAG 320 64 V+
IOPIN 320 64 Out
FLAG 320 272 V-
IOPIN 320 272 In
SYMBOL diode 96 128 R180
WINDOW 0 24 72 Left 0
WINDOW 3 24 0 Left 0
SYMATTR InstName D1
SYMATTR Value MUR460
SYMBOL diode 208 128 R180
WINDOW 0 24 72 Left 0
WINDOW 3 24 0 Left 0
SYMATTR InstName D2
SYMATTR Value MUR460
SYMBOL diode 96 272 R180
WINDOW 0 24 72 Left 0
WINDOW 3 24 0 Left 0
SYMATTR InstName D3
SYMATTR Value MUR460
SYMBOL diode 208 272 R180
WINDOW 0 24 72 Left 0
WINDOW 3 24 0 Left 0
SYMATTR InstName D4
SYMATTR Value MUR460
TEXT -56 328 Left 0 !.model D1 D(Ron=.01 Roff=1Meg Vfwd=.1)\n.model D2 D(Ron=.01 Roff=1Meg Vfwd=.1)\n.model D3 D(Ron=.01 Roff=1Meg Vfwd=.1)\n.model D4 D(Ron=.01 Roff=1Meg Vfwd=.1)