[sdiy] Schmitt Trigger Questions

[harrybissell]

Ok a sort of answer...

the CMOS schmitt triggers give you NO control over the thresholds...
they are quite fast but they vary from unit to unit and VERY (vary) from
manufacturer to manufacturer.

I remember one chip (national imho) where the schmitt trigger input to
a counter was the SECOND stage... so a slow moving input would get
trashed by the first stage, then the trash would be squared up by the
schmitt trigger. VERY dumb... I only hope it was to avoid a patent and not
just sheer stupidity. Imagine how well THAT worked when they switched to that
chip in production...

H^) harry

Scott Gravenhorst wrote:

> The discussion of the 3080 schmitt trigger induces a question or two:
>
> Can anyone comment on a comparison between the 3080 and LM13x00 OTA schmitt
> triggers?
>
> What about CMOS inverter based schmitt triggers?
>
> 4069UB and 4007UB show a 30 or 40 nanosecond propagation delay (10 volts)
> in general, but there's nothing given about a schmitt trigger arrangement.
>  Are these as fast, faster or slower than OTAs when used as schmitt triggers?
>
> ---------------------------------------------------------
> - Where merit is not rewarded, excellence fades.
> - Hydrogen is pointless without solar.
> - What good are laws that only lawyers understand?
> - The media's credibility should always be questioned.
> - The only good terrorist is a dead terrorist.
> - Governments do nothing well, save collect taxes.
>
> -- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
> -- Linux Rex         | RedWebMail by RedStarWare
> -- FatMan: home1.gte.net/res0658s/FatMan/
> -- NonFatMan: home1.gte.net/res0658s/electronics/
> -- Autodidactic Master of Arcane and Hidden Knowledge.