Version 4
SHEET 1 880 680
WIRE -112 288 -112 208
WIRE -112 384 -112 288
WIRE -96 208 -112 208
WIRE -80 288 -112 288
WIRE -80 384 -112 384
WIRE 32 208 16 208
WIRE 48 208 32 208
WIRE 48 288 -16 288
WIRE 48 288 48 208
WIRE 48 384 -16 384
WIRE 48 384 48 288
WIRE 48 416 48 384
WIRE 48 496 48 480
WIRE 64 208 48 208
WIRE 80 288 48 288
WIRE 80 384 48 384
WIRE 208 208 176 208
WIRE 208 288 144 288
WIRE 208 288 208 208
WIRE 208 384 144 384
WIRE 208 384 208 288
WIRE 208 416 208 384
WIRE 208 496 48 496
WIRE 208 496 208 480
WIRE 208 512 208 496
WIRE 224 208 208 208
WIRE 240 288 208 288
WIRE 240 384 208 384
WIRE 368 208 336 208
WIRE 368 288 304 288
WIRE 368 288 368 208
WIRE 368 384 304 384
WIRE 368 384 368 288
WIRE 368 416 368 384
WIRE 368 496 208 496
WIRE 368 496 368 480
FLAG 208 512 0
FLAG 32 208 O
FLAG 208 208 240
FLAG 368 208 120
SYMBOL diode -16 272 R90
WINDOW 0 16 66 VBottom 0
WINDOW 3 -12 -22 VTop 0
SYMATTR InstName D1
SYMATTR Value 1N914
SYMBOL diode -80 368 M90
WINDOW 0 16 -4 VBottom 0
WINDOW 3 -12 89 VTop 0
SYMATTR InstName D2
SYMATTR Value 1N914
SYMBOL cap 192 416 R0
WINDOW 0 41 6 Left 0
WINDOW 3 39 33 Left 0
SYMATTR InstName C1
SYMATTR Value 100n
SYMBOL diode 144 272 R90
WINDOW 0 16 66 VBottom 0
WINDOW 3 -12 -22 VTop 0
SYMATTR InstName D3
SYMATTR Value 1N914
SYMBOL diode 80 368 M90
WINDOW 0 16 -4 VBottom 0
WINDOW 3 -12 89 VTop 0
SYMATTR InstName D4
SYMATTR Value 1N914
SYMBOL cap 32 416 R0
WINDOW 0 41 6 Left 0
WINDOW 3 39 33 Left 0
SYMATTR InstName C2
SYMATTR Value 100n
SYMBOL diode 304 272 R90
WINDOW 0 16 66 VBottom 0
WINDOW 3 -12 -22 VTop 0
SYMATTR InstName D5
SYMATTR Value 1N914
SYMBOL diode 240 368 M90
WINDOW 0 16 -4 VBottom 0
WINDOW 3 -12 89 VTop 0
SYMATTR InstName D6
SYMATTR Value 1N914
SYMBOL cap 352 416 R0
WINDOW 0 41 6 Left 0
WINDOW 3 39 33 Left 0
SYMATTR InstName C3
SYMATTR Value 100n
SYMBOL Dig_Add\\TTL\\HCT\\74hct14 -48 160 R0
SYMATTR InstName U1
SYMATTR SpiceLine VCC={Vc}  SPEED=1.0  TRIPDT=1e-9
SYMBOL Dig_Add\\TTL\\HCT\\74hct14 112 160 R0
SYMATTR InstName U2
SYMBOL Dig_Add\\TTL\\HCT\\74hct14 272 160 R0
SYMATTR InstName U3
TEXT -110 480 Left 0 !.tran .5m
TEXT -112 424 Left 0 !.inc 74hct.lib\n.inc 74hc.lib
TEXT -112 512 Left 0 !.step param Vc 5 13 4