Version 4
SHEET 1 1384 680
WIRE 352 96 -64 96
WIRE 480 96 352 96
WIRE 352 128 352 96
WIRE 480 128 480 96
WIRE -64 192 -64 96
WIRE 352 224 352 192
WIRE 352 224 240 224
WIRE 480 224 480 192
WIRE 576 224 480 224
WIRE 768 224 656 224
WIRE 1088 224 960 224
WIRE 1328 224 1168 224
WIRE 1328 240 1328 224
WIRE 240 256 240 224
WIRE 352 272 352 224
WIRE 480 272 480 224
WIRE 768 320 720 320
WIRE 1328 320 960 320
WIRE -64 368 -64 272
WIRE 352 368 352 336
WIRE 352 368 -64 368
WIRE 480 368 480 336
WIRE 480 368 352 368
WIRE 720 368 720 320
WIRE 720 544 720 448
FLAG 240 256 0
FLAG 720 544 0
SYMBOL res 672 208 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 75k
SYMBOL Optos\\PC817A 864 272 R0
SYMATTR InstName U1
SYMBOL res 1184 208 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 4.7k
SYMBOL voltage 1328 224 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value 5
SYMBOL diode 368 192 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D1
SYMBOL diode 336 272 R0
SYMATTR InstName D3
SYMBOL diode 496 336 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D4
SYMBOL diode 464 128 R0
SYMATTR InstName D2
SYMBOL voltage -64 176 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value SINE(0 240 50)
SYMBOL res 704 352 R0
SYMATTR InstName R3
SYMATTR Value 75k
TEXT -98 418 Left 2 !.tran 500ms