[time-nuts] looking for SMT oscillator SC cut, with no oven
Hal Murray
hmurray at megapathdsl.net
Thu Aug 27 03:58:27 EDT 2015
kb8tq at n1k.org said:
>> Is there anything fundamental about SC that forces the turn over
temperature
>> to be high?
> Simple answer yes. More complicated answer : that depends.
> The crystal curve on an AT or an IT centers roughly at room temperature.
> When you fiddle the angles to get a stress compensated blank, that center
> point moves up to the 90 to 100 C range.
Thanks. I guess I thought there was an extra degree of freedom so you could
pick the turn over temperature.
The graph at the bottom of this URL
http://www.4timing.com/techcrystal.htm
shows that there are actually 3 turn over temperatures. Do AT crystals used
in ovens take advantage of the UTP?
----------
So we are just lucky that an AT cut works well at a convenient temperature
and that an SC cut works well with an oven. A life form on some other star
might not be so lucky.
--
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