Version 4
SHEET 1 1388 776
WIRE -80 -512 -592 -512
WIRE 272 -512 -80 -512
WIRE 272 -160 272 -512
WIRE 432 -160 272 -160
WIRE 784 -160 432 -160
WIRE 64 -112 -368 -112
WIRE -80 -32 -80 -512
WIRE 272 -32 272 -160
WIRE 64 -16 64 -112
WIRE 224 -16 64 -16
WIRE 624 0 288 0
WIRE 784 0 784 -160
WIRE 896 0 784 0
WIRE 1344 0 976 0
WIRE 224 16 144 16
WIRE 1344 96 1344 0
WIRE -80 112 -80 48
WIRE 144 112 144 16
WIRE 144 112 -80 112
WIRE -368 144 -368 -112
WIRE 256 208 256 32
WIRE 528 208 256 208
WIRE 624 224 624 0
WIRE 1344 224 1344 160
WIRE 1344 224 624 224
WIRE 432 272 432 -160
WIRE 432 272 288 272
WIRE -80 288 -80 112
WIRE 288 320 288 272
WIRE 64 336 64 -16
WIRE 240 336 64 336
WIRE 1344 336 1344 224
WIRE 624 352 304 352
WIRE 240 368 176 368
WIRE -592 384 -592 -512
WIRE 896 384 752 384
WIRE 992 384 976 384
WIRE -80 400 -80 368
WIRE 176 400 176 368
WIRE 176 400 -80 400
WIRE 992 400 992 384
WIRE 1344 400 992 400
WIRE -80 512 -80 400
WIRE 1344 528 1248 528
WIRE 272 544 272 384
WIRE 528 544 528 208
WIRE 528 544 272 544
WIRE 1344 544 1344 528
WIRE 624 560 624 352
WIRE 752 560 752 384
WIRE 752 560 624 560
WIRE 896 560 752 560
WIRE 1248 560 1248 528
WIRE 1248 560 976 560
WIRE -592 768 -592 464
WIRE -368 768 -368 224
WIRE -368 768 -592 768
WIRE -80 768 -80 592
WIRE -80 768 -368 768
WIRE 272 768 272 544
WIRE 272 768 -80 768
WIRE 1344 768 1344 608
WIRE 1344 768 272 768
SYMBOL voltage -592 368 R0
SYMATTR InstName V1
SYMATTR Value 240mV
SYMBOL res -96 -48 R0
SYMATTR InstName R1
SYMATTR Value 25
SYMBOL res -96 272 R0
SYMATTR InstName R2
SYMATTR Value 25
SYMBOL res -96 496 R0
SYMATTR InstName R3
SYMATTR Value 50
SYMBOL voltage -368 128 R0
SYMATTR InstName V2
SYMATTR Value PULSE(50mV 200mV 0 10 10 0 20)
SYMBOL res 992 -16 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R4
SYMATTR Value 390
SYMBOL res 992 368 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R5
SYMATTR Value 270
SYMBOL res 992 544 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R6
SYMATTR Value 390
SYMBOL diode 1328 96 R0
SYMATTR InstName D1
SYMBOL diode 1328 336 R0
SYMATTR InstName D2
SYMBOL diode 1328 544 R0
SYMATTR InstName D3
SYMBOL OpAmps/LM108A 256 -64 R0
SYMATTR InstName U3
SYMBOL OpAmps/LM108A 272 288 R0
SYMATTR InstName U4