Many discussion such as signal, piezo device, range, and amplifier are explained in this tutorial. Inside this tutorial the reader can find information regarding the piezo device, leakage, and gain.
The tutorial presents things around sensor interfacing, piezo, and interfacing. The following are excerpted from this tutorial:
Interfacing Piezo to the signatureACE® System Piezoelectric transducers like IMCO, HELM Load Plugs, or load probes, or Kistler piezo load sensors or accelerometers require a different technique than strain gages. The piezo device is a self-generating sensor that produces energy that is proportional to deformation of the piezo element. Note that I used the word ENERGY – not current or voltage. The piezo device will produce a certain amount of energy when it is squeezed, but will also extract the same amount of energy when it is released. What is required to properly see the output of a piezo device is a “Charge Amplifier” which can be formed by connecting a capacitor across the + and – Signal inputs of the TEC™ module.
Furthermore, this tutorial presents info regarding signal inputs, sensor, and sensors.