Version 4
SHEET 1 1044 680
WIRE -176 272 -176 144
WIRE -176 464 -176 352
WIRE -96 320 -96 240
WIRE -96 464 -176 464
WIRE -96 464 -96 384
WIRE -96 480 -96 464
WIRE -80 304 -80 224
WIRE -48 464 -96 464
WIRE -48 464 -48 176
WIRE -32 144 -176 144
WIRE -32 368 -32 144
WIRE -16 240 -96 240
WIRE -16 400 -16 240
WIRE 0 176 -48 176
WIRE 0 240 -16 240
WIRE 0 304 -80 304
WIRE 0 368 -32 368
WIRE 240 144 -32 144
WIRE 240 176 224 176
WIRE 240 176 240 144
WIRE 240 304 224 304
WIRE 240 400 -16 400
WIRE 240 400 240 304
WIRE 272 176 240 176
WIRE 272 304 240 304
WIRE 272 368 224 368
WIRE 272 384 272 368
WIRE 272 464 -48 464
WIRE 272 464 272 448
WIRE 352 240 224 240
WIRE 384 176 352 176
WIRE 384 208 384 176
WIRE 384 304 352 304
WIRE 384 304 384 272
FLAG -96 480 0
FLAG -80 224 Out
IOPIN -80 224 Out
SYMBOL Robertugo\\555_ALL 160 288 R0
WINDOW 38 -89 81 Left 0
WINDOW 0 -62 -81 Left 0
SYMATTR InstName U1
SYMBOL Robertugo\\Pote 368 176 R0
WINDOW 123 113 92 Center 0
SYMATTR InstName U2
SYMATTR Value Rt=20K
SYMATTR Value2 Set={Cursor}
SYMBOL res 368 288 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName RToffB
SYMATTR Value 1k
SYMBOL res 368 160 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName RtOnA
SYMATTR Value 1k
SYMBOL cap -112 320 R0
WINDOW 0 21 8 Left 0
WINDOW 3 19 64 Left 0
SYMATTR InstName Ct
SYMATTR Value 10n
SYMBOL cap 256 384 R0
WINDOW 0 21 8 Left 0
WINDOW 3 19 64 Left 0
SYMATTR InstName Cbp
SYMATTR Value 10n
SYMBOL voltage -176 256 R0
WINDOW 3 -13 59 Left 0
SYMATTR InstName Vcc
SYMATTR Value 12
TEXT 400 184 Left 0 ;RtOnB
TEXT 400 296 Left 0 ;RtOffA
TEXT 166 482 Left 0 !.tran 5m
TEXT -872 152 Left 0 !.params: Vdd 12 Ronx=.1 \n.step param Cursor  0 1 .2\n.meas tran ta FIND time WHEN V(out)={Vdd/2} td=1m rise=1\n.meas tran tb FIND time WHEN V(out)={Vdd/2} td=1m rise=11\n.meas tran Frec PARAM 10/(tb-ta)\n.Meas tran Tc FIND time WHEN V(Out)={Vdd/2} td=1m fall=1\n.Meas tran Td FIND time WHEN V(Out)={Vdd/2} td=1m fall=2\n.Meas tran T1 Param  (Tc-Ta)\n.Meas tran T2  Param  (Td-Ta)\n.Meas tran Ton Param If (T1>0, T1, T2)\n.Meas tran Duty% Param  Ton*Frec*100