Version 4
SHEET 1 880 680
WIRE 96 240 48 240
WIRE 224 240 160 240
WIRE 224 272 224 240
WIRE 48 368 48 240
WIRE 224 368 224 352
WIRE 224 368 48 368
WIRE 48 384 48 368
FLAG 48 384 0
SYMBOL voltage 224 256 R0
WINDOW 0 -14 57 Left 0
WINDOW 123 0 0 Left 0
WINDOW 39 -97 97 Left 0
SYMATTR InstName V1
SYMATTR SpiceLine Rser=1
SYMATTR Value 1
SYMBOL SwTime 128 240 R0
SYMATTR SpiceLine Ton={Ton}
SYMATTR SpiceLine2 Toff={Toff}
SYMATTR InstName X1
TEXT 64 168 Left 0 !.tran {Ton+Toff*1.1}
TEXT 64 200 Left 0 !.Param Ton=1 Toff=1.5