Re: A2 Rev 0 Recreation Update #2

[glen herrmannsfeldt <gah@ugcs.caltech.edu>]

(someone wrote)

> > There are two types of crystals:  series resonant and parallel
> > resonant.  Sounds like you need the "other" type (and I don't
> > recall which it is ;-).

The main difference between series and parallel resonant is that
thickness, and so the resonant frequency, is a little different.

If you have the wrong type it will usually work but at the
wrong frequency.  Some higher frequency crystals, maybe more
than about 20MHz, are designed to run on a higher harmonic
(actually, overtone) such as the third, and if one isn't
careful will run on the fundamental at a much lower frequency.
(Because of end effects it isn't exactly three times
for a third overtone crystal.)

-- glen