Roger Hayter wrote on 11/19/2017 4:45 AM:
rickman wrote:

snip

I have seen no reasonable explanation of how a reed switch is any more
analog than a mechanical switch. They are both analog movements of a
mechanism. The only difference is one adjusts a magnetic field while the
other applies pressure to a spring which bends (again in an analog manner)
until it begins to make contact with another spring. Which will have more
jitter? Only a measurement will say and the reed switch has a much lower
time of bouncing, so will not possibly have a noticeable jitter in time of
actuation.

I agree that jitter is not a major issue, but I do think that with a
mechanical switch that human muscles and brain are directly part of the
analogue feedback loop controlling jitter in a way they may not be with
an intervening magnetic link. At least with a straight key, if springs
are part ot the system then your argument is more convincing. This is a
different issue from contact bounce, which occurs after the initial
contact closure.

Can you explain how the two differ? Just saying they are different isn't an
explanation.

Of course any key has to have a spring for returning the key to home
position. Every key I've seen had at least two adjustments, home position
(and therefore the travel to contact closure) and spring tension.

Bounce time is still and issue because most debounce circuits use a simple
RC to resolve the bounce time and this adds delay to the contact closure
time as seen by the equipment.

--

Rick C

Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998