[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.



-- 
These are my opinions.  I hate spam.





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