[R-390] 17 MHz Crystal

[Bob Camp]

Hi

Yup, it's a bad thing to do email after several beers…

Bob

On May 15, 2013, at 10:14 AM, Barry <n4buq at knology.net> wrote:

> Is that ratio expressed correctly?  It seems that should be a diameter to thickness ratio > 100 (or it's Wednesday and I'm not thinking clearly...).
> 
> Thanks,
> Barry - N4BUQ
> 
>> Hi
>> 
>> In a crystal like the one shown the frequency is determined by the
>> thickness. That's generally true of any crystal in the > 1 MHz
>> frequency range. To make things work ( Q / resistance / trim range)
>> you need a thickness to diameter ratio > 100. That all gets
>> impractical as you go down in frequency, so you go to cuts that
>> resonate in other ways.
>> 
>> Bob
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