"cooldude" schreef in bericht
ups.com...
Hi,

1) Is there any equivalent to monostable in fully digital electronics
(logic gates)? I am trying to trigger a pulse (a set width) with a very
narrow recovery time (in the range of 100ns or less) before the next.
74LS221 seems to work although getting weird pulses (very short
retrigger pulses) occasionally.


All monostables in that region I'm aware of, use RC for the timing.
(Although that R is not necessarily an external one.)

Sam mentioned the necessity of powerline decoupling already. Another cause
of spourious pulses are distorted trigger signals. Long lines (wires) or
component mismatch are known for that.


2) And also whats the difference between the normal monostable and the
precision ones? As the name suggested they'd be more precise
triggering?


Generally speaking you should expect more precise timing. That's to say the
pulse duration should be less depended on the IC and more or only on the
external components. But the slogan "precision" can be interpreted in more
ways. So the real properties should be extracted from the datasheets.

3) Would 74HCT version will be more suitable although I read somewhere
they are slower than the ls version.


Once more the datasheet(s) should tell you.


Thanks,
John


petrus bitbyter