Design of a driver for measurements with piezoelectric elements

For the experimental measurements, we needed to solve design of the power supply of the amplifier for the piezoceramic transducers used for sound sensing. A special operational amplifier with FET transistors at the input was used in the setup. A minor drawback is the necessity for a symmetrical 4.5 V power supply, which can be solved with a plate (9 V) battery and a virtual ground, where we ran into the problem of how to protect the device from accidental reverse polarity when connecting the battery. In this paper, the parameters of several standard semiconductor diodes and transistors are compared and based on the results, we have selected a component for an energy-optimal solution. With only minimal modification of the circuitry and a slightly higher cost of the component, a better utilization of the energy stored in the primary battery can be obtained. Also, for a device with high demands on the supply voltage level, this is solvable by wiring it with the right type of FET transistor. The proposed circuit was also tested and used to measure the piezo acoustic signal as an output from a real experiment with the coating process used in improving the surface properties of the magnesium alloy sample.