Version 4
SHEET 1 2220 784
WIRE -784 112 -848 112
WIRE -192 112 -544 112
WIRE 176 112 -192 112
WIRE -960 160 -1024 160
WIRE -912 160 -960 160
WIRE -656 160 -720 160
WIRE -608 160 -656 160
WIRE -176 160 -240 160
WIRE 176 160 176 112
WIRE 176 160 48 160
WIRE -960 192 -960 160
WIRE -656 192 -656 160
WIRE -1024 208 -1024 160
WIRE -720 208 -720 160
WIRE -544 224 -544 208
WIRE -480 224 -544 224
WIRE -336 224 -400 224
WIRE -176 224 -336 224
WIRE 80 224 48 224
WIRE -848 272 -848 208
WIRE 176 272 176 160
WIRE -656 288 -656 272
WIRE -560 288 -656 288
WIRE -400 288 -560 288
WIRE -176 288 -400 288
WIRE 80 288 48 288
WIRE -1024 320 -1024 288
WIRE -720 320 -720 288
WIRE -384 320 -480 320
WIRE -336 320 -336 224
WIRE -336 320 -384 320
WIRE -384 336 -384 320
WIRE -192 352 -192 112
WIRE -176 352 -192 352
WIRE 112 352 48 352
WIRE -336 384 -336 320
WIRE 80 384 80 288
WIRE 80 384 -336 384
WIRE 176 384 176 352
WIRE 176 384 144 384
WIRE 144 400 144 384
WIRE -848 416 -848 352
WIRE -480 416 -480 320
WIRE -480 416 -848 416
WIRE -1024 432 -1024 400
WIRE -784 432 -784 112
WIRE -784 432 -1024 432
WIRE -720 432 -720 400
WIRE -720 432 -784 432
WIRE -384 432 -384 400
WIRE -384 432 -720 432
WIRE -240 432 -240 160
WIRE -240 432 -384 432
WIRE 112 432 112 416
WIRE 112 432 -240 432
WIRE 176 432 176 384
WIRE 176 432 112 432
WIRE -960 448 -960 272
WIRE -560 448 -560 288
WIRE -560 448 -960 448
FLAG 144 400 0
FLAG -400 288 Out
IOPIN -400 288 Out
FLAG 80 224 Od
IOPIN 80 224 Out
SYMBOL cap -368 400 R180
WINDOW 0 24 54 Left 0
WINDOW 3 24 8 Left 0
SYMATTR InstName Ct
SYMATTR Value 1n
SYMATTR SpiceLine V=50v
SYMBOL 555_ALL -16 272 R0
WINDOW 38 -83 78 Left 0
SYMATTR InstName U1
SYMBOL cap 128 416 R180
WINDOW 0 72 11 Left 0
WINDOW 3 24 8 Left 0
SYMATTR InstName Cbp
SYMATTR Value 10n
SYMATTR SpiceLine V=50v
SYMBOL voltage 176 256 R0
WINDOW 0 -51 22 Left 0
WINDOW 3 -29 58 Left 0
SYMATTR InstName V+
SYMATTR Value {Vdd}
SYMBOL npn2 -608 112 R0
WINDOW 0 -70 31 Left 0
WINDOW 3 21 50 Left 0
SYMATTR InstName Qmark
SYMATTR Value BC548A
SYMBOL res -672 176 R0
SYMATTR InstName R1
SYMATTR Value 10k
SYMBOL voltage -720 304 R0
WINDOW 0 35 35 Left 0
WINDOW 3 38 69 Left 0
WINDOW 123 0 0 Left 0
WINDOW 39 -29 86 Left 0
SYMATTR InstName Vmark
SYMATTR Value 10
SYMBOL res -736 192 R0
SYMATTR InstName R2
SYMATTR Value 10k
SYMBOL res -384 208 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 -25 19 VTop 0
SYMATTR InstName R3
SYMATTR Value 390
SYMBOL res -976 176 R0
SYMATTR InstName R4
SYMATTR Value 10k
SYMBOL res -1040 192 R0
SYMATTR InstName R5
SYMATTR Value 10k
SYMBOL pnp2 -912 112 R0
WINDOW 0 -82 33 Left 0
WINDOW 3 23 50 Left 0
SYMATTR InstName QSpace
SYMATTR Value BC558A
SYMBOL res -832 368 R180
WINDOW 0 36 76 Left 0
WINDOW 3 36 40 Left 0
SYMATTR InstName R6
SYMATTR Value 390
SYMBOL voltage -1024 304 R0
WINDOW 0 -28 59 Left 0
WINDOW 3 13 106 Left 0
WINDOW 123 0 0 Left 0
WINDOW 39 -29 86 Left 0
SYMATTR InstName Vspc
SYMATTR Value 4
TEXT -136 128 Left 0 !.tran 300u
TEXT 216 136 Left 0 !.params: Vdd 15 Ronx=.1 pot=91k\n;.step param x .01 .99 .49\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