Re: [CAD_CAM_EDM_DRO] Re: TTL uncovered?

awemawson wrote:

> --- In CAD_CAM_EDM_DRO@y..., "mjf462001" <mjf462001@y...> wrote:
> > Gretings,
> >
> > Is there an online source that explains what
> > TTL signals are, what TTL stands for, specifications,
> > or any further information on TTL signals?

TTL : Transistor-Transistor Logic, a now obsolete digital logic family from the
mid 1970s. Low (logic 0) is 0 to .4 V, High (logic 1) is 2.2 to 5 V, roughly.
Different families (74, 74S, 74ALS, 74LS, 74HC, 74HCT etc.) have different
values for the minimum voltage they will positively accept as a logic high,
but the above values are good for all but HC, which wants about 2.7 V
for a safe minimum logic 1. The original CMOS family, CD4000 can be
run on 3 to 12 Volts, so the logic levels are determined by the supply
voltage. Running on +5 V, it is compatible just like the 74HC family.

Jon