The characteristics of new piezoelectric ballast for fluorescent T8 lamp

The characteristics of a novel piezoelectric ballast for fluorescent T8 lamp are investigated in this study. A piezoelectric transformer is used in new piezoelectric ballast in place of a conventional ignition inductor. A piezoelectric transformer is circular in form, which is poled to thickness direction and is vibrated to radial direction. The step-up ratio, temperature rise, and efficiency of the piezoelectric transformer fabricated are about 1.2, 10/spl deg/C, and 97%, respectively. The ballast using the piezoelectric transformer is a type of series resonant half bridge inverter. To resonate with piezoelectric transformer and to preheat the lamp, a 2 mH inductor and 2.2 nF preheating capacitor are used. As the results, output power and power factor of new piezoelectric ballast are about 30 W and 0.99.