20 Oct
2006
20 Oct
'06
12:42 a.m.
On Thursday 19 October 2006 09:35 pm, Ethan Dicks wrote:
I have a small handful of crystals and was wondering
what the easiest
way to divine their frequencies... I can say that I'm reasonably
certain that all of them are between 32.768Khz and 50MHz, but some are
blank, and some have non-obvious cryptic markings. What I'm looking
for is some simple way to get them to oscillate and measure them with
a frequency counter (i.e. - assume one is starting with a working,
trustable frequency counter).
Is it as simple as a pair of inverters/NANDs in the classic crystal
loop, or is that circuit massively frequency dependent (i.e. - works
for 1Mhz-10Mhz, not faster or slower...)?
I'd go with CMOS, myself -- any inverting gate should do it. Put some
high-value resistance across it to bias it (10M?), and you may need a cap or
two at either end to get the crystal going. Maybe run it off a 9V battery?
I have a bunch I need to test too. :-)
--
Member of the toughest, meanest, dealiest, most unrelenting -- and
ablest -- form of life in this section of spac, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin