Tuning fork motional resistance

[GK]

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[ejeffrey]

The data sheet says -0.034 +- 0.006 ppm/C^2, so I think that is a pretty good estimate.

Edit: Sorry, I realize now you are worrying about the resistance, not the frequency.  I don't think you should have to worry about that over the operating range.  Are you planning to use some odd circuit?

[ejeffrey]

Hmm... yeah, that is pretty far outside the target use of these devices.  You might look for information on tuning fork AFM.  They use the same tuning forks but they care a lot more about all the details of the electrical properties.   I can ask a few people next week to see if they have any idea, but I suspect that popping it in a toaster oven or heating it with a hair dryer is the easiest way to go.  Sometimes an hour in the lab can save a day in the library, at least if you already have a setup to test the performance.

[SeanB]

Simplest is to solder them all to a grounded copper trace and cover the top and bottom of the board around them with a thin polystyrene sheet to make them all track thermally. No need to heat them, just keep all at the same temperature, and make sure all are from the same production batch, which probably will mean ordering 50 or so and matching them for resonant frequency using a simple oscillator. May take a while to find the 5, as they will have to be kept in an isothermal enclosure and tested individually whilst not heating or cooling them.