Phase-controlled technique through thyristors (SCR) is used instead of diodes in order to form a power converter. Output voltage of this power converter can be varied by controlling the firing angle of SCR and is used to charge the capacitor banks. Each firing angles are referred to zero-crossing point of each half of the 50 Hz AC voltage. Adjustable voltage is then used to charge the capacitor bank inside Capacitor Charging Power Supply (CCPS) for Xenon flashlamp driver. Flashlamp produced source of pulsed light that pumped the Nd:YAG laser crystal. The Nd:YAG laser usually operates at various input energies, thus requiring variable values of voltage to charge the capacitor bank. Developed phase-controlled converter can steadily controll the output voltage of CCPS from 500 V to 1000 V...

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This study demonstrates the wafer bonding method for performance tuning of piezoelectric Micromachined Ultrasonic Transducer (pMUT) from on-the-shelf piezoelectric disc (PZT). Polydimethylsiloxane (PDMS) and Epoxy were studied as adhesive materials. A thick bonding layer was deposited using the spin coating technique. Wafer bonding was carried out at room temperature to simulate in-situ pMUT repairing scenario. Bonding integrity is analyzed using Field Emission Scanning Electron Microscope (FESEM) images, while electrical characterization of pMUT is carried out using impedance analysis. Fabricated pMUTs have been calibrated using the pulse-echo technique in a freshwater tank. This study found that PDMS at the minimum thickness of 28 ?m is preferably compatible for in-situ wafer bonding of pMUT compared to the Epoxy. PDMS has significantly reduced device impedance at 62.4 % reduction compared to 58.9 % reduction for Epoxy. Both pMUTs were able to transmit and receive short acoustic ping.....

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