Version 4
SHEET 1 880 680
WIRE 240 112 112 112
WIRE 112 160 112 112
FLAG 112 240 0
SYMBOL voltage 112 144 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value PULSE(0 1 0 10n 10n {0.5/freq} {1/freq})
TEXT -232 96 Left 2 !.par freq=1000
TEXT -234 264 Left 2 !.tran 100m