Take the 2-minute tour ×
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It's 100% free.

The following document describes signal conditioning circuits for Piezeoelectric sensors. I was interested in knowing which model should I use when designing signal conditioning circuit for piezelectric sensor.

http://www.ti.com/lit/an/sloa033a/sloa033a.pdf

share|improve this question
    
Great, thanks for the link. (+1) I've always used the voltage model. (mostly 'cause voltage sources are more common... I can think about my function generator, and the (voltage) step response. The current model is more physical. And of course they are both the same Thevenin-wise. –  George Herold Nov 3 '14 at 23:35

3 Answers 3

If you can limit the load capacitance of the cable and amplifier, you can use the voltage model. This requires that no cable is involved as cables tend to add 20~30 pF/ft.

Otherwise the charge model must be used and a charge amplifier is required. This is how accelerometers work with cables from sensor to amp.

share|improve this answer
    
Could you provides more information, in class they said that you have to use it based on the natural frequency of the piezoelectric sensor. Sorry I wouldn't have to be asking here if the prof provided proper lectures notes. –  Anonymous Nov 27 '12 at 0:39

You can find some advantages and disadvantages of the approaches here:

Piezoelectric transducers - Endevco Tech Paper

share|improve this answer

Note that if you use the charge amplifier, then the cable capacitance does not impact the low frequency corner. For me, this is the big difference between the two styles. If a more stable low frequency corner is important, and you have cabling issues to deal with (particularly when there may be cable motion), then in many cases a charge amplifier is the way to go.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.