How the resonance is induced in the micromechanical resonator?

[Millan87]

Hello, I want to know if someone can explain me how the resonance is induced in micromechanical resonator please? Is it with a piezoelectric crystal?

Edited December 9, 2020 by Millan87

[swansont]

What do you mean the "resonance is induced"?  A vibration would be induced. A resonance is a specific condition of such a vibration (it's close to a natural mode of the structure) The resonance will depend on the design of the resonator. If you mean adjusting the resonance, that is often a function of temperature.

For inducing an oscillation, a PZT could be used. IIRC some micromechanical resonators have electronic characteristics (e.g. a capacitance), so you could induce an oscillatory current or voltage to induce vibrations. It could be induced by radiation pressure (i.e.bouncing a EM standing wave off of it)

[Millan87]

First of all, thank you for your answer which allows me to better understand the subject.

Regarding of my meaning of "inducing the resonance", I will contextualize my question. I am interested in a technology / method called Blue-Ray-based micromechanical resonator which allows to follow the change in mass of material attached to the surface of microbridges thanks to the resonance change of these microbridges. In the article I read, it is stated that "Microbridges were actuated by means of a piezoelectric crystal, which was set to linearly sweep a range of frequencies in the vicinity of the theoretically predicted resonance frequency. ”. Having little knowledge in the field, I wonder about the function of this piezoelectric crystal and therefore I find it difficult to grasp its usefulness in the method.
If you can help me it would be great.

Thanks

Edited December 9, 2020 by Millan87

[swansont]

54 minutes ago, Millan87 said:

First of all, thank you for your answer which allows me to better understand the subject.

Regarding of my meaning of "inducing the resonance", I will contextualize my question. I am interested in a technology / method called Blue-Ray-based micromechanical resonator which allows to follow the change in mass of material attached to the surface of microbridges thanks to the resonance change of these microbridges. In the article I read, it is stated that "Microbridges were actuated by means of a piezoelectric crystal, which was set to linearly sweep a range of frequencies in the vicinity of the theoretically predicted resonance frequency. ”. Having little knowledge in the field, I wonder about the function of this piezoelectric crystal and therefore I find it difficult to grasp its usefulness in the method.
If you can help me it would be great.

Thanks

To say it was actuated means that's how they started the motion or oscillation. They used different frequencies so they could measure the response and determine the resonance - the frequency where energy was added to the oscillator most efficiently.

Using a PZT (piezoelectric transducer) makes sense, as certain piezos have a range of frequencies where they will respond.

As an analogy, if you wanted to ring a bell and find its resonant frequency, you could use a frequency generator and a speaker, slowly ramp the frequency and detect the bell's response. That's basically what's being described, except they are using mechanical stimulus with a PZT.

 

 

[Millan87]

Thank you very much, I understand better now, your help was useful to me.