Version 4
SHEET 1 880 680
WIRE 16 128 -96 128
WIRE 288 128 16 128
WIRE 304 128 288 128
WIRE 448 128 384 128
WIRE 48 160 0 160
WIRE 288 160 288 128
WIRE 288 160 272 160
WIRE 528 176 512 176
WIRE 48 224 32 224
WIRE 288 224 272 224
WIRE 400 224 368 224
WIRE 448 224 400 224
WIRE -96 256 -96 128
WIRE 400 256 400 224
WIRE 416 256 400 256
WIRE -32 288 -32 256
WIRE 48 288 -32 288
WIRE 288 288 272 288
WIRE 400 288 400 256
WIRE 400 288 288 288
WIRE 528 304 528 176
WIRE 528 304 320 304
WIRE 400 320 400 288
WIRE 16 352 16 128
WIRE 48 352 16 352
WIRE 320 352 320 304
WIRE 320 352 272 352
WIRE -96 368 -96 336
WIRE -64 368 -96 368
WIRE -64 384 -64 368
WIRE 32 384 32 224
WIRE 288 384 288 288
WIRE 288 384 32 384
WIRE -96 416 -96 368
WIRE 0 416 0 160
WIRE 0 416 -96 416
WIRE 400 416 400 384
WIRE 400 416 0 416
FLAG -32 256 Out
IOPIN -32 256 Out
FLAG -64 384 0
FLAG 416 256 Ramp
IOPIN 416 256 Out
SYMBOL voltage -96 240 R0
WINDOW 0 10 14 Left 0
WINDOW 3 -13 57 Left 0
SYMATTR InstName V+
SYMATTR Value 12
SYMBOL Robertugo\\555_ALL 208 272 R0
WINDOW 38 -86 82 Left 0
WINDOW 0 -62 -82 Left 0
SYMATTR InstName U1
SYMBOL cap 384 320 R0
WINDOW 0 -35 34 Left 0
WINDOW 3 -33 61 Left 0
SYMATTR InstName Ct
SYMATTR Value 10n
SYMBOL res 400 112 R90
WINDOW 0 64 73 VBottom 0
WINDOW 3 36 21 VTop 0
SYMATTR InstName Rton
SYMATTR Value 10k
SYMBOL res 384 208 R90
WINDOW 0 64 70 VBottom 0
WINDOW 3 36 14 VTop 0
SYMATTR InstName Rtoff
SYMATTR Value 1k
SYMBOL pnp2 512 224 R180
WINDOW 0 -5 97 Left 0
WINDOW 3 22 47 Left 0
SYMATTR InstName Q1
SYMATTR Value 2N3906
TEXT -90 146 Left 0 !.tran 1m
TEXT 48 400 Left 0 ;Duty>50%