Version 4
SHEET 1 880 680
WIRE -240 288 -240 192
WIRE -240 464 -240 368
WIRE -160 288 -160 256
WIRE -160 464 -240 464
WIRE -160 464 -160 368
WIRE -128 256 -160 256
WIRE -128 480 -128 256
WIRE -96 192 -240 192
WIRE -96 240 -96 192
WIRE -96 352 -96 320
WIRE -96 368 -96 352
WIRE -96 480 -128 480
WIRE -96 480 -96 448
WIRE -16 272 -16 208
WIRE -16 352 -96 352
WIRE -16 352 -16 336
WIRE 48 352 -16 352
WIRE 48 352 48 336
WIRE 48 384 48 352
WIRE 48 464 -160 464
WIRE 48 464 48 448
WIRE 64 208 -16 208
WIRE 64 224 64 208
WIRE 80 352 80 336
WIRE 128 208 64 208
WIRE 128 368 128 208
WIRE 160 352 80 352
WIRE 160 352 160 208
WIRE 160 464 48 464
WIRE 160 496 160 464
WIRE 208 368 128 368
WIRE 208 368 208 336
WIRE 224 208 160 208
WIRE 224 224 224 208
WIRE 240 368 240 336
WIRE 240 384 240 368
WIRE 240 464 160 464
WIRE 240 464 240 448
WIRE 336 208 224 208
WIRE 336 272 336 208
WIRE 336 368 240 368
WIRE 336 368 336 336
WIRE 400 192 -96 192
WIRE 400 272 400 192
WIRE 400 368 336 368
WIRE 400 368 400 352
WIRE 400 384 400 368
WIRE 400 480 -96 480
WIRE 400 480 400 464
FLAG 160 496 0
SYMBOL Dig_Add\\TTL\\HC&U\\74hc02 0 288 R270
WINDOW 0 -5 44 VRight 0
SYMATTR InstName U1a
SYMATTR SpiceLine VCC={v}  SPEED=1.0  TRIPDT=1e-9
SYMBOL Dig_Add\\TTL\\HC&U\\74hc02 160 288 R270
WINDOW 0 -4 42 VRight 0
SYMATTR InstName U1b
SYMATTR SpiceLine VCC={v}   SPEED=1.0  TRIPDT=1e-9
SYMBOL cap 32 384 R0
SYMATTR InstName C1
SYMATTR Value .1n
SYMBOL cap 224 384 R0
SYMATTR InstName C2
SYMATTR Value .1n
SYMBOL diode 0 336 R180
WINDOW 0 -31 1 Left 0
WINDOW 3 24 0 Invisible 0
SYMATTR InstName D1
SYMATTR Value 1N914
SYMBOL diode 352 336 R180
WINDOW 0 24 72 Left 0
WINDOW 3 24 0 Invisible 0
SYMATTR InstName D2
SYMATTR Value 1N914
SYMBOL voltage -240 272 R0
WINDOW 0 -16 60 Left 0
WINDOW 3 -8 60 Invisible 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName Vc
SYMATTR Value PULSE(0 50 0 .5u .5u 0 1u)
SYMBOL res 384 256 R0
WINDOW 0 -26 67 Left 0
WINDOW 3 -38 94 Left 0
SYMATTR InstName R1
SYMATTR Value 10k
SYMBOL res -112 224 R0
SYMATTR InstName R2
SYMATTR Value 10k
SYMBOL res 384 368 R0
WINDOW 0 -26 67 Left 0
WINDOW 3 -38 94 Left 0
SYMATTR InstName R3
SYMATTR Value 6k8
SYMBOL voltage -160 272 R0
WINDOW 0 2 9 Left 0
WINDOW 3 -7 60 Left 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V+
SYMATTR Value {v}
SYMBOL res -112 352 R0
SYMATTR InstName R4
SYMATTR Value 6k8
TEXT -74 176 Left 0 !.tran 1u uic
TEXT 192 176 Left 0 !.param v 5