Radiating Barkhausen-Type Pulses During Generation of High-Voltage Pulse by Piezoelectric Igniters

The modified Barkhausen method was applied to investigate ageing properties of the Barkhausen-type pulse (BTP) series during the generation of high-voltage pulses by piezoelectric igniters (PI). The BTP series of sufficiently high voltage are superposed with the high-voltage pulse. They are present on different sections of the high-voltage pulse. Single BTP duration is about 25-40 ns at the base, and each of them emits an electromagnetic (EM) pulse in the ultra-high frequency range. With the increase in the number of PI operations, the amplitude of the high-voltage pulse became lower, and the BTP series changed their parameters. It was described the generation of the BTP series as the response of cyclic domain switching in the self-excitation mode during voltage induced polarization changes in the plumbum-zirconat-titanate (PZT) cylinders of PIs. As PIs ages, the piezoelectric response and the encapsulation of the cylinders in the dielectric became weaker. A hypothesis has been put forward that mechanical coupling between the encapsulated cylinders and electromechanical coupling inside the cylinders leads to the synchronous operation of the two "fresh" cylinders. After weakening of the couplings in the aged PIs, pulses in the BTP relaxation series increase their amplitudes and repetition rate. The general randomization of the whole series also increases, which corresponds to the emitting of long broadband chaotic EM signals.