simulating piezo sensor SOLVED

hi CL friends, i have this (working) circuit i just re-built with circuitlab. does anyone have pointers on piezoelectric element simulation? i know simulating real world sensors is a tricky thing...

& thanks nerdKit for this cool tool! amazing JS achievement

by yoshco
March 03, 2012

Hey @yoshco, I see two immediate issues before you get any further into piezoelectrics directly. One is that your 5V source doesn't have a name, which causes simulation problems. Name it "V1". Alternatively, just use a node name like "+5V" and connect it directly to the rail of the op-amp. (The second op-amp rail connection is also left un-connected! You should at least ground it if that was your intent.)

The second problem I see is that the inputs of the op-amp are reversed from where they should be to make a non-inverting amplifier. The + input should go to the input source, and the - (inverting) input should go to the resistor divider that is setting your gain. So with the rest of the circuit as-is, the + should be on top, and - on bottom. You can simply click to select the op-amp, and then press "V" to "Flip Vertical", which will put the connections where you want them to be.

Hope that helps!

by mrobbins
March 11, 2012

Also, keep in mind that with piezos you can generate a very large spike and if you are using them to transduce a guitar the spikes are usually the cause of the quack and sizzle. /;-=( Do something to mitigate the spike and the rest is easier. Also, gain is less important than input impedance. The piezo impedance drops as freq goes up, making them lousy in the lows and sizzly in the highs. A very high input Z mitigates this, as does a low Z out. And a higher voltage supply to allow for wider spikes and swings.

by guitars48
March 11, 2012

thank you for the comments, would be nice to get a notification on replays.

again thanks for this amazing addition for my toolbox

by yoshco
March 12, 2012

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