Version 4
SHEET 1 1972 992
WIRE 368 -64 -288 -64
WIRE 1376 -32 1344 -32
WIRE 1584 -32 1456 -32
WIRE 1136 -16 1072 -16
WIRE 800 0 -96 0
WIRE 1072 16 1072 -16
WIRE 1136 16 1136 -16
WIRE 1424 16 1136 16
WIRE 1504 16 1424 16
WIRE 1504 32 1504 16
WIRE 800 48 800 0
WIRE 64 80 16 80
WIRE 320 80 288 80
WIRE 368 80 368 -64
WIRE 368 80 320 80
WIRE 480 80 368 80
WIRE 1216 80 1200 80
WIRE 1664 80 1632 80
WIRE 1824 80 1792 80
WIRE 16 96 16 80
WIRE 1424 112 1424 16
WIRE 1072 128 1072 96
WIRE 1136 128 1072 128
WIRE 1200 128 1200 80
WIRE 1248 128 1200 128
WIRE 1344 128 1344 -32
WIRE 1344 128 1328 128
WIRE 1392 128 1344 128
WIRE 64 144 -16 144
WIRE 400 144 288 144
WIRE 1584 144 1584 -32
WIRE 1584 144 1456 144
WIRE 1632 144 1632 80
WIRE 1632 144 1584 144
WIRE 1696 144 1632 144
WIRE 1792 144 1792 80
WIRE 1792 144 1760 144
WIRE 1824 144 1792 144
WIRE -288 160 -288 -64
WIRE 800 160 800 128
WIRE 800 160 752 160
WIRE 848 160 800 160
WIRE 1072 160 1072 128
WIRE 1072 160 1040 160
WIRE 1104 160 1072 160
WIRE 1392 160 1360 160
WIRE 480 176 480 160
WIRE 752 176 752 160
WIRE 1360 176 1360 160
WIRE 1824 176 1824 144
WIRE -96 208 -96 0
WIRE -96 208 -128 208
WIRE 64 208 -96 208
WIRE 368 208 288 208
WIRE 1424 208 1424 176
WIRE 800 256 752 256
WIRE 848 256 800 256
WIRE 1040 256 1040 240
WIRE 1120 256 1040 256
WIRE 64 272 16 272
WIRE 448 272 288 272
WIRE 528 272 448 272
WIRE 1120 288 1120 256
WIRE 1824 288 1824 256
WIRE 448 320 448 272
WIRE 800 320 800 256
WIRE 16 336 16 272
WIRE 320 336 320 80
WIRE 320 336 16 336
WIRE -288 352 -288 240
WIRE -112 352 -288 352
WIRE -288 384 -288 352
WIRE -16 384 -16 144
WIRE 368 384 368 208
WIRE 368 384 -16 384
WIRE 448 400 448 384
WIRE 544 400 448 400
WIRE -112 416 -112 352
WIRE 400 416 400 144
WIRE 400 416 -112 416
WIRE 1824 416 1824 368
WIRE 448 464 448 400
WIRE -288 512 -288 464
WIRE -16 512 -16 384
WIRE -16 512 -288 512
WIRE -288 528 -288 512
WIRE 1824 528 1824 496
WIRE 448 576 448 544
WIRE -288 624 -288 592
WIRE 448 672 448 656
FLAG 480 176 0
FLAG 448 672 0
FLAG 544 400 A
FLAG 528 272 B
FLAG 16 96 0
FLAG -288 624 0
FLAG -128 208 C
FLAG 800 320 0
FLAG 1120 288 0
FLAG 1360 176 0
FLAG 1504 112 0
FLAG 1424 288 0
FLAG 1104 160 D
FLAG 1216 80 E
FLAG 1664 80 F
FLAG 1824 80 G
FLAG 1824 528 0
SYMBOL Misc\\NE555 176 176 R0
SYMATTR InstName U1
SYMBOL voltage 480 64 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 5V
SYMBOL voltage 448 448 R0
WINDOW 3 -261 66 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value SINE(0 200mV 2k)
SYMBOL voltage 448 560 R0
WINDOW 3 -406 60 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value PULSE(-.6 .6 0 10u 10u 1m 2m)
SYMBOL voltage 1504 16 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V4
SYMATTR Value 5V
SYMBOL voltage 1424 192 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V5
SYMATTR Value -5V
SYMBOL Opamps\\OP27 1424 80 R0
SYMATTR InstName U2
SYMBOL Optos\\PC817A 944 208 R0
SYMATTR InstName U4
SYMBOL cap 432 320 R0
SYMATTR InstName C3
SYMATTR Value 4.7µF
SYMBOL res 784 32 R0
SYMATTR InstName R19
SYMATTR Value 100
SYMBOL res -304 144 R0
SYMATTR InstName R1
SYMATTR Value 10k
SYMBOL res -304 368 R0
SYMATTR InstName R2
SYMATTR Value 20k
SYMBOL cap -304 528 R0
SYMATTR InstName C2
SYMATTR Value 1nF
SYMBOL res 736 160 R0
WINDOW 0 -80 42 Left 2
WINDOW 3 -149 66 Left 2
SYMATTR InstName R3
SYMATTR Value {Light_Loss}
SYMBOL res 1056 0 R0
SYMATTR InstName R20
SYMATTR Value 1k
SYMBOL cap 1200 112 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C9
SYMATTR Value 0.1µF
SYMBOL res 1344 112 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R21
SYMATTR Value 1k
SYMBOL res 1472 -48 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 -28 -4 VTop 2
SYMATTR InstName R22
SYMATTR Value 20k
SYMBOL cap 1760 128 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C10
SYMATTR Value 220µF
SYMBOL ind 1808 160 R0
SYMATTR InstName L_speaker
SYMATTR Value 100µH
SYMBOL res 1808 272 R0
SYMATTR InstName R_speaker
SYMATTR Value 8
SYMBOL res 1808 400 R0
SYMATTR InstName R23
SYMATTR Value 100
TEXT 520 -96 Left 2 !.tran 0 2.2m 0 1u
TEXT 520 -64 Left 2 !.param Light_Loss 50
TEXT 528 -24 Left 2 !.step param Light_Loss list 26 29 40