For testing the electric and fluidic performances of the system an experimental electrical setup was established.
The setup is composed of a signal generator, an amplifier allow a maximum voltage of 200 V, an oscilloscope for
control the vibration state of the membrane and measure voltages really applied and a CCD camera for imaging the
mixing process.
To evaluate mixing efficiency a solution of colored water of about 50 μl was deposited manually on the top side
of the membrane. The actuation of the PZT was performed in the range between 5 and 30 kHz sine wave at
different voltages values. The obtained results show different modes of mixing which reproduce the vibration modes
of the membrane. The mixing was particularly observed at the eigenmode of the membrane as shown in Fig. 2. Theresults show that the fundamental mode is observed at about 9 kHz, the mode (2, 1) at about 21 kHz and the (2, 2)
mode at about 28 kHz, see Fig. 2 (a), (b) and (c) respectively.
Fig.