electronic devices and circuits

[prashank6]

i want to amplify the voltage acquired from a piezoelectric transducer , what is the best possible circuit for such a purpose. i mean should i use a trnsistor or an op-amp, if so the could anyone please tell me the model no of then op-amp that i should use.
i also want to know that which transducer or sensor should i use to to obtain a 3V or higher potential difference on application of a very small mechanical force on the transducer (by small i mean , the force that we use in touchscreen devices)

 

[MacGyverS2000]

Have you even tried to Google for such a circuit?

Dan - Owner

http://www.Hi-TecDesigns.com

 

[IRstuff]

"i also want to know that which transducer or sensor should i use to to obtain a 3V or higher potential difference on application of a very small mechanical force on the transducer (by small i mean , the force that we use in touchscreen devices)"

Use a touchscreen, of course...

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

 

[BeckyVala]

I think your asking the wrong question: generally the voltage provided by a PZT device is high but not strong. I.E. you need to buffer the signal. To do this you should choose an opamp with FETs on the input. Any instrumentation Amp should do. Then the circuit will just be the buffered amp which will give the same voltage out (Vo) but when you load it, it will not go to zero. If you then still need to amplify the voltage use a dual or quad (instrumentation) amp and just feed the output from the buffer (Vo) via an input resistor (Ri) into the next stage where you'll use the feedback resistor (Rf). The ratio of input Vo.Rf/Ri will give you your output voltage from the second stage (Vo2)...you may as well use large resistance values (i.e. in the 100k range and above to minimize power. I've attached a hand drawn schematic. Also note that this allows for you to only run in one direction. If you wanted a push/pull force you'd need to set an offset in the buffer using a voltage divided from your V++ rail to ground. You've also not stated the range of your ADC input or are you just using this as a trigger? Anyway good luck.

B.

 

[MikeHalloran]

The circuit you're looking for, to get a voltage signal out of a piezo block, is commonly called a charge amplifier. It's really a charge to voltage converter plus a voltage amplifier, but everyone calls it a charge amp.

Its input impedance is necessarily so high that baking the input cable makes a difference. I'm guessing that the layout and material selection also makes a difference, so you might be better off just buying it as a module instead of building it.



Mike Halloran
Pembroke Pines, FL, USA