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Topic: Using Low votage audio amplifier with a piezo electric sensor. (Read 860 times) previous topic - next topic

krazatchu

IIRC, all the legs were in series.
For hookup, you will want to research Wheatstone bridge, a couple of links:

http://www.maxim-ic.com/app-notes/index.mvp/id/3426
http://en.wikipedia.org/wiki/Wheatstone_bridge

The sensors should have four wires, with two active elements and two passive.
Essentially it is two resistive dividers where one is reference and the other changes.

The output of these two dividers is treated as a differential signal going into the AD623...
The instrumentation amp gives an output that is the difference between the two inputs...
Michael
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http://www.krazatchu.ca

Chorvath

Hmm, thanks for the info and help.

The sensors in my scale have three wires black, red, and white.

krazatchu

Sounds like the load cell is only half a Wheatstone bridge, a resistive divider, you can verify this with a multimeter..
It would be wise to add a divider for reference, that way small fluctuations in supply will be canceled...

Michael
----------------------
http://www.krazatchu.ca

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