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In this study, DC-DC converter using the thickness–vibration-mode piezoelectric transformer for driving high brightness LED was manufactured and its driving properties were investigated. LED output voltage of DC 4.11 V which can be feasibly turned on was observed. At the time, driving frequency of 1.12 MHz was measured. When the high brightness LED was turned on for 40 min., the surface temperature of the piezoelectric transformer under 2.5 W input power showed the temperature rise of 17°C. Its temperature was saturated after 25 min. after turning on and driving frequency slightly decreased as the temperature of the piezoelectric transformer increased. The high brightness LED was stably turned on at the frequency of 1.12 MHz.

In this paper, ultrasonic nozzle and driving circuit were manufactured and their electrical properties were investigated. Ultrasonic nozzle was fabricated using Pb[(Sb1/2Nb1/2)0.035(Mn1/3Nb2/3)0.065(Zr0.49Ti0.51)0.90]O3+ 0.5wt%PbO (abbreviated as PSN-PMN-PZT) ceramics showing excellent piezoelectric characteristics. In order to drive ultrasonic nozzle, Pulse Width Modulation controller (abbreviated as PWM) of KA3525A was used. With increasing the input voltage of nozzle, average diameter of fuel oil droplet was increased up to 16 V and then decreased. At the input voltage of 12 V, volume average diameter of fuel oil droplet showed the minimum value of 37.3 μm and also at the input voltage of 16 V, volume average diameter of fuel oil droplet showed the maximum value of 51.3 μm.

In this paper, multilayer actuator structured-ultrasonic nozzle and resonant inverter driving circuit were manufactured, respectively. Its electrical properties were investigated. Multilayer actuator structured ultrasonic nozzle was fabricated using PMN-PNN-PZT ceramics showing excellent piezoelectric characteristics. In order to drive ultrasonic nozzle, resonant PWM inverter was used. The purpose of this study is to find the optimal driving condition of ultrasonic nozzle. Accordingly, electrical and temperature characteristic of multilayer ultrasonic driving system were investigated by experiments as a function of the series resonance inductance. The driving current of ultrasonic nozzle showed the maximum current of 27 mA. Also, the surface temperature of ceramic vibrator showed at driving time for 20 min. The ultrasonic nozzle was stably operated in the case of driving for more than 20 min.