[SOLVED] Piezoelectric vs. MEMS accelerometers

[senmeis]

Hi,

Is it correct that piezoelectric accelerometers generally have higher resolution than MEMS ones?

Senmeis

 

[vivekroy]

Piezoelectric accelerometers is a subset of MEMS acceloremeters. Can you please provide a little more information?

An accelerometer works by measuring the displacement of a proof mass suspended on a "spring like beam" when accelerated. MEMS accelerometers means that entire arrangement is fabricated on a micro-scale. But there can be different ways to measure the displacement... You can do it by piezoelectric means, piezoresistive means or even capacitive means.

 

[FvM]

Is it correct that piezoelectric accelerometers generally have higher resolution than MEMS ones?

A piezoelectric accelerometers https://en.wikipedia.org/wiki/Piezoelectric_accelerometer can be made quite sensitive by using a large seismic mass. But in contrast to usual MEMS accelerometers, it can't detect static gravitation.

 

[vivekroy]

Sensitivity of any accelerometer can be increased by using a larger mass. MEMS accelerometers can be made employing piezoelectric sensors although it will suffer from the said issue.
Reference: "An introduction to microelectromechanical systems engineering", Nadim Maluf et al. [Chapter: MEM Structures and Systems in Industrial and Automotive Applications]

 

[senmeis]

Please find the source of this statement in the attachment.

Senmeis

 

[vivekroy]

Your enclosed statement implies.. "Piezoelectric sensing is better than variable capacitance (VC) type of sensing in MEMS. "
This is completely different from your question.

 

[senmeis]

OK, is this understanding correct: PE is better than VC but both can belong to MEMS?

Senmeis

 

[vivekroy]

Yeah. MEMS --> mechanical systems on a micro-scale. But the sensing needs to be done in someway or the other. In this case, it is either VC or piezoelectric.