11 Mar
2005
11 Mar
'05
8:21 a.m.
is adjusted to give an output pulse width on pin#1 of
the 74LS121
of 5.5 ls." I assume "ls" is an oddball abbreviation for microsecond?
The l comes from the misinterpretation of the 'micro' symbol, a long
tailed u. Anyhow 5.5us is correct and going from the resistor values
and T=CR for the 74121 gives a value of 275pF. 270pF will do but with
the range of adjustment in the circuit anything from 100pF to 500pF
should work.
Lee.
.
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