Abstract A body of ceramic piezoelectric material of the lead titanate, lead zirconate type with an additive of the iron oxide type is provided having regions electroded and polarized such that the electrical impedances are markedly different. High voltage transformations are obtained in this manner between input and output electrodes. A third set of electrodes coupled to one of the other sets of electrodes enables the transformer to accomplish self-oscillation. In order to enable the body to be supported at more than one vibration node, the body is caused to vibrate at a harmonic of its fundamental frequency of vibration or more precisely in a mode with one full acoustic wavelength along the ceramic body, or two or more half wavelengths.
A piezoelectric transformer having length, width, and thickness dimensions comprising in combination: a body composed of a ceramic composition of essentially lead zirconate and lead titanate with an alkaline earth metal material substituted for a portiOn of the lead; the body having first and second regions, the first region of which is electrically poled parallel to the thickness dimension of the body which is the body''s smallest dimension, and the second region of which is electrically poled parallel to the width dimension of the body which is larger than the thickness dimension and smaller than the length dimension of the body; a width electrode applied to a face of said body in said second region; a pair of thickness electrodes applied to said body in said first region to apply a driving electric field parallel to the said thickness dimension with one of said pair of thickness electrodes serving as a common electrode with said width electrode; said transformer being adapted to be driven at resonance by said driving electric field with the resonance frequency controlled by said width dimension and with the output voltage appearing between the said width electrode and said common electrode and the output electric field being substantially parallel to the width dimension of said body.