Version 4
SHEET 1 880 680
WIRE -48 -32 -176 -32
WIRE 336 -32 -48 -32
WIRE 528 -32 336 -32
WIRE -176 -16 -176 -32
WIRE 0 16 -96 16
WIRE 336 16 336 -32
WIRE 0 32 0 16
WIRE -48 80 -48 -32
WIRE -176 96 -176 64
WIRE -96 96 -96 16
WIRE -96 96 -176 96
WIRE -80 96 -96 96
WIRE 0 112 0 96
WIRE 0 112 -16 112
WIRE 16 112 0 112
WIRE 128 112 96 112
WIRE 336 112 336 96
WIRE 336 112 320 112
WIRE 384 112 336 112
WIRE 528 112 528 -32
WIRE -176 128 -176 96
WIRE -80 128 -96 128
WIRE -48 160 -48 144
WIRE 128 208 112 208
WIRE 336 208 320 208
WIRE -176 240 -176 208
WIRE 112 240 112 208
WIRE 336 240 336 208
WIRE 528 240 528 192
WIRE -48 256 -48 240
WIRE -96 304 -96 128
WIRE 384 304 384 112
WIRE 384 304 -96 304
FLAG -176 240 0
FLAG 336 240 0
FLAG -48 256 0
FLAG 528 240 0
FLAG 112 240 0
SYMBOL Optos\\PC817D 224 160 R0
SYMATTR InstName U1
SYMBOL Opamps\\LT1357 -48 48 R0
SYMATTR InstName U2
SYMBOL res 112 96 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R1
SYMATTR Value 1k
SYMBOL res 320 0 R0
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL res -192 -32 R0
SYMATTR InstName R3
SYMATTR Value 1k
SYMBOL res -192 112 R0
SYMATTR InstName R4
SYMATTR Value 1k
SYMBOL voltage 528 96 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 15V
SYMBOL voltage -48 256 R180
WINDOW 0 -66 67 Left 0
WINDOW 3 -79 39 Left 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value 15V
SYMBOL cap -16 32 R0
WINDOW 0 25 -24 Left 0
WINDOW 3 25 6 Left 0
SYMATTR InstName C1
SYMATTR Value 5pF
TEXT -228 326 Left 0 !.tran 0 1ms 0 10ns