On 4/16/2012 7:04 AM, Mauro Mariotti wrote:
> Hi,
>

I would hook up the geophone to the WINSDR program
with no damping then excite it somehow then
convert the PSN file to a wave file and examine
the spectrum in the Audacity program.
It can show you an FFT Waterfall display
and is free for personal use if you
are not making money at what you do.
But also the FFT within WinQuake can also
show you the spike at F0.
Resonance.



> also better is to bias the coil with a small battery.
> A simple AA battery (also one with just a residual of charge).
> Connect an oscilloscope or other suitable device to the sensor output.
> Atthe same time connect the battery - to ground of oscilloscope and the
> use the + of battery to excite the geophone.
> Do this all with the geophone in its natural position (horizontal if it
> is horizontal sensitivity, or vertical if it is a vertical sensitivity
> one).
> You will see a nice swing when you release the + bias from the sensor.
> The time between of the top of two sequential wave crest tell you the
> period, and its reciprocal is the freqency.
>
> best regards
> Mauro
>
> Il 16/04/2012 02:23, Tiago Agrelos ha scritto:
>> Hi.
>>
>> I´ve small geophone almost a year, but i never knew its natural
>> frequency, how can i "find" its approximate natural frequency?
>>
>> The geophone doesnt have anything written on it, its smaller than 4.5Hz
>> L15B geophone sold by Larry, generate a lot more output than the 4.5Hz
>> one and i read 380ohm from it.
>>
>> I appreciate any help.
>>
>> Regards,
>> Tiago.
>

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