On Fri, 14 Jun 2002, Lawrence Lile wrote:

>Series cut .. Parallel cut - How does one figure out which applies to the
>crystal in question.  I just looked at EVERY crystal in Digikey, and NONE
>(i.e. diddlysquat, Nada, Nichts, Nyet, Zip, Zilcho) specify whether the
>crystal is parallel or serial cut.  Now there are a few that allude to
>"When run in parallel mode.."  "Effective series resistance"  And one has a
>whole paragraph of rubber language which basically says "Your Mileage May
>Vary" when run in parallel or series mode, but none of them just come right
>out and say one or the other.
>
>I guess the correct method is to use a CRYSTAL ball.  <Groan>

Last time I checked Mouser specified both cut and required capacitance.

The correct method to determine crystal cut is a spectrum analyzer with
tracking generator (or a noise box) which will tell you what you want to
know immediately. You can substitute a VXO for the specan using the same
crystal (buy two) and a RF signal meter. When you use the VXO the second
crystal will be between it and the signal meter. You will have one peak
and one trough. The peak is the serial f. and the trough the parallel f.
Make sure that the reactive crystal load does not pull the VXO (use a
buffer). A counter will tell you exactly where you are. Note that you are
doing exactly what the specan is doing. Some grid dip meters will work as
VXO if you fit a crystal. Mine does not ...

hope this helps,

Peter

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