Just because it resonates doesn't mean that the AMPLITUDE of the resonance
is +/- 10 microns. This will depend on the spring constant over the
operating range (presumably +/11 microns or more) and the excitation energy.
Another way to put this is turn up the volume! At 18khz an audio drive would
work just fine, and you can buy mucho watts (excitation energy) real cheap.

Vic

----- Original Message -----
From: ll 
To: 
Sent: Thursday, March 07, 2002 2:26 PM
Subject: [mems-talk] inertial sensor testing


> Dear group members,
>
> Now I suffer a problem on inertial switch testing. My switch is made of
> spring-mass structure which can sensitive to acceleration. When there is a
> accelaration, the switch will be in ON state. Now I put it on a
> shaker(sinusoidal input) to test it using the theory that the displacement
> of my switch's mass will be larger when my switch is vibrating at its
> resonant frequency. My switch's resonant frequency is about 18kHz (it is a
> little high:). ), the mass need to travel 10micron to reach its ON state.
>
> SO here comes my PROBLEM: I sweep my shaker output frequency from 100Hz to
> 20kHz BUT can't get any ON signal!!!
>
> Does anyone has experience of this situation?
>
> It can be vibrated at its resonant frequency even this frequency is high,
> is that right?
>
> Is 10 micron a large displacement for micro device to travel?
>
> Is there other method to detect if the device does vibrate and also its
> resonant frequency?
>
> Please pay attension to my long story and give me wonderful reply:)
>
> Best,
>
> Vickie
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