Crystal frequency tuning

Wendy

Joined Mar 24, 2008
21,914
Only in a fine tweak manner, you can move the last few digits around. The whole point of the crystal is frequency doesn't shift much. Make one of the 20pf variables.
 

t_n_k

Joined Mar 6, 2009
5,447
This is probably a hijack but a curiosity from my past. In the 60's a class mate was a keen ham operator. In those days one could extract the crystal from the holder itself. He mentioned to me he was up-shifting a crystal by "grinding" it on a flat surface with toothpaste as the grinding medium. I loved the practical bent that ham operators seemed to manifest as a matter of course.:)
 

Thread Starter

LDC3

Joined Apr 27, 2013
924
This is probably a hijack but a curiosity from my past. In the 60's a class mate was a keen ham operator. In those days one could extract the crystal from the holder itself. He mentioned to me he was up-shifting a crystal by "grinding" it on a flat surface with toothpaste as the grinding medium. I loved the practical bent that ham operators seemed to manifest as a matter of course.:)
I don't think I want to go to this extreme to change a frequency. After I grind off some of the crystal, I would need to test the frequency. Then propablely grind off some more, remount the crystal, and so on ..... :)
 

MrChips

Joined Oct 2, 2009
19,753
Depends on how much you want to change the frequency. Crystals are stable to about 5 ppm. You can tweak it around 50 ppm, 0.005% that's it.
 

THE_RB

Joined Feb 11, 2008
5,438
That first circuit re post #1 has a pot to adjust the xtal drive, that pot will probably allow some trimming of freq itself.
 
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